Journal articles on the topic 'Aeronautical complex structures'
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1
Rodríguez, Rosamaria, A. Yarza, J. López-Díez, C. Cuerno-Rejado, and A. Güemes. "Damage Detection on Typical Aeronautical Structures." Key Engineering Materials 293-294 (September 2005): 677–84. http://dx.doi.org/10.4028/www.scientific.net/kem.293-294.677.
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The paper pursues the exploration of the feasibility and reliability of current damage detection technologies, evaluating their detection capabilities, environmental factors effects, false alarms rate, adaptability to complex geometries, etc. The method to be used is based on finite element modal updating. Three aspects, as outlined below, are covered: testing samples will be aluminium sheets (0.6m x 0.4m x 1.6mm) strengthened with riveted L-shaped stiffeners. Data will be presented from the undamaged specimens. Secondly, the testing of the samples with damage simulated at different places by temporary removal of specific rivets, thus affecting the overall structural characteristics of the structure. The models used for damage identification methods will be fine tuned to properly detect the simulated damages. Finally, using this information, the paper resumes the capabilities of the method to detect and locate the simulated damage.
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Proietti, Alice, Nicola Gallo, Denise Bellisario, Fabrizio Quadrini, and Loredana Santo. "Damping Behavior of Hybrid Composite Structures by Aeronautical Technologies." Applied Sciences 12, no. 15 (August 8, 2022): 7932. http://dx.doi.org/10.3390/app12157932.
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Hybrid composite laminates are manufactured by using technologies and raw materials of the aeronautic sector with the aim to improve the damping behavior of composite structures. Matrix hybridization was achieved by laminating carbon fiber reinforced (CFR) plies with elastomer interlayers. Up to 10 different composite sandwich architectures were investigated by changing the stacking sequence, the thickness of the elastomer layers, and the elastomer typology, whereas the total number of the CFR plies was fixed to six for all the hybrid composites. Square panels with the size of 300 × 300 mm2 were autoclave molded with vacuum bagging, and rectangular samples were extracted for static and dynamic tests. Dynamic mechanical analyses were performed to measure the storage modulus and loss factor of hybrid materials, which were compared with static and dynamic performances of the composite structures under bending. Repeated loading–unloading cycles and free oscillation tests allowed us to the energy loss per unit of volume, and the acceleration damping, respectively. Results show that softest elastomer interlayers lead to big loss of stiffness without any positive effect in the damping behavior, which worsens as well. By using soft elastomers, complex architectures do not provide any additional benefit in comparison with the traditional sandwich structure with soft core and hard skins.
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Oboe, Daniele, Luca Colombo, Claudio Sbarufatti, and Marco Giglio. "Shape Sensing of a Complex Aeronautical Structure with Inverse Finite Element Method." Sensors 21, no. 4 (February 17, 2021): 1388. http://dx.doi.org/10.3390/s21041388.
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The inverse Finite Element Method (iFEM) is receiving more attention for shape sensing due to its independence from the material properties and the external load. However, a proper definition of the model geometry with its boundary conditions is required, together with the acquisition of the structure’s strain field with optimized sensor networks. The iFEM model definition is not trivial in the case of complex structures, in particular, if sensors are not applied on the whole structure allowing just a partial definition of the input strain field. To overcome this issue, this research proposes a simplified iFEM model in which the geometrical complexity is reduced and boundary conditions are tuned with the superimposition of the effects to behave as the real structure. The procedure is assessed for a complex aeronautical structure, where the reference displacement field is first computed in a numerical framework with input strains coming from a direct finite element analysis, confirming the effectiveness of the iFEM based on a simplified geometry. Finally, the model is fed with experimentally acquired strain measurements and the performance of the method is assessed in presence of a high level of uncertainty.
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Efimov, V. V. "On the matter of the terminology of aeronautical structures survivability." Dependability 19, no. 2 (June 16, 2019): 42–47. http://dx.doi.org/10.21683/1729-2646-2019-19-2-42-47.
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Aim. The paper examines the existing definitions of survivability and damage tolerance (operational survivability) of aeronautical structures. An attempt is made to unambiguously define the survivability of aeronautical structures that can subsequently be extended to an aircraft as a whole and other complex technical items. The primary goal of this paper is to clearly distinguish between dependability and survivability. In order to ensure efficient operation and flight safety, an aircraft must possess airworthiness, a comprehensive characteristic of an aircraft that is defined by the implemented design principles and solutions and that allows performing safe flights under expected conditions and under the established methods of operation. The expected operating conditions are described in the Aviation Regulations – Airworthiness Requirements. Despite the fact that compliance with the Airworthiness Requirements ensures a sufficiently high level of flight safety, the most vital structural components are designed in such a way as to remain operable even under extreme conditions beyond the expected operating conditions. But dependability cannot be responsible for operability outside the expected operating conditions. Conclusion suggests itself that under extreme conditions beyond the expected operating conditions operability is to be ensured by another property, i.e. survivability. Methods. This research was conducted using the logical and probabilistic approaches. The author examined literary sources primarily dedicated to the matters of dependability and survivability of aeronautical structures, as well as other complex technical items. In order to ensure an optimal understanding of the differences and correlation between the concepts of dependability and survivability, the probabilistic approach was used. Results. Upon the analysis of literary sources, survivability was defined as the property of an item to retain in time the capability to perform the required functions under extreme conditions beyond the expected operating conditions under the specified methods of maintenance, storage and transportation. Additionally, the paper proposes the definition of damage tolerance (operational survivability) as the property of an item to retain in time the capability to perform the required functions under extreme conditions beyond the expected operating conditions depending on the methods of maintenance, storage and transportation. The probabilistic approach to the delimitation of the concepts of dependability and survivability of aeronautical structures was examined using the known indicator of operating efficiency of a transport aircraft that is represented as the mathematical expectation of the efficiency indicator. An aircraft may be either in the expected operating conditions or in extreme conditions beyond the expected operating conditions. No third option exists. Then, the sum of the probabilities of an aircraft encountering such conditions must be equal to one. The probability of no-failure can be calculated by means of the probability of the contrary event, i.e. the probability of failure that can be represented as the product of the probability of an aircraft encountering certain operating conditions and the probability of failure in such conditions. For the case of extreme conditions beyond the expected conditions the well-known concepts of perishability and vulnerability with the author’s improvements can be used. Conclusions. A definition of survivability was obtained that is clearly different from the concepts of dependability and fail-safety. Additionally, the concept of damage tolerance (operational survivability) was proposed that was introduced similarly to the previously introduced concept of operational dependability.
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Efimov, V. V. "On the matter of the terminology of aeronautical structures survivability." Dependability 19, no. 2 (June 16, 2019): 43–48. http://dx.doi.org/10.21683/1729-2646-2019-19-2-43-48.
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Aim. The paper examines the existing definitions of survivability and damage tolerance (operational survivability) of aeronautical structures. An attempt is made to unambiguously define the survivability of aeronautical structures that can subsequently be extended to an aircraft as a whole and other complex technical items. The primary goal of this paper is to clearly distinguish between dependability and survivability. In order to ensure efficient operation and flight safety, an aircraft must possess airworthiness, a comprehensive characteristic of an aircraft that is defined by the implemented design principles and solutions and that allows performing safe flights under expected conditions and under the established methods of operation. The expected operating conditions are described in the Aviation Regulations – Airworthiness Requirements. Despite the fact that compliance with the Airworthiness Requirements ensures a sufficiently high level of flight safety, the most vital structural components are designed in such a way as to remain operable even under extreme conditions beyond the expected operating conditions. But dependability cannot be responsible for operability outside the expected operating conditions. Conclusion suggests itself that under extreme conditions beyond the expected operating conditions operability is to be ensured by another property, i.e. survivability. Methods. This research was conducted using the logical and probabilistic approaches. The author examined literary sources primarily dedicated to the matters of dependability and survivability of aeronautical structures, as well as other complex technical items. In order to ensure an optimal understanding of the differences and correlation between the concepts of dependability and survivability, the probabilistic approach was used. Results. Upon the analysis of literary sources, survivability was defined as the property of an item to retain in time the capability to perform the required functions under extreme conditions beyond the expected operating conditions under the specified methods of maintenance, storage and transportation. Additionally, the paper proposes the definition of damage tolerance (operational survivability) as the property of an item to retain in time the capability to perform the required functions under extreme conditions beyond the expected operating conditions depending on the methods of maintenance, storage and transportation. The probabilistic approach to the delimitation of the concepts of dependability and survivability of aeronautical structures was examined using the known indicator of operating efficiency of a transport aircraft that is represented as the mathematical expectation of the efficiency indicator. An aircraft may be either in the expected operating conditions or in extreme conditions beyond the expected operating conditions. No third option exists. Then, the sum of the probabilities of an aircraft encountering such conditions must be equal to one. The probability of no-failure can be calculated by means of the probability of the contrary event, i.e. the probability of failure that can be represented as the product of the probability of an aircraft encountering certain operating conditions and the probability of failure in such conditions. For the case of extreme conditions beyond the expected conditions the well-known concepts of perishability and vulnerability with the author’s improvements can be used. Conclusions. A definition of survivability was obtained that is clearly different from the concepts of dependability and fail-safety. Additionally, the concept of damage tolerance (operational survivability) was proposed that was introduced similarly to the previously introduced concept of operational dependability.
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Rahbari, Amirhossein, Marc Rébillat, Nazih Mechbal, and Stephane Canu. "Unsupervised damage clustering in complex aeronautical composite structures monitored by Lamb waves: An inductive approach." Engineering Applications of Artificial Intelligence 97 (January 2021): 104099. http://dx.doi.org/10.1016/j.engappai.2020.104099.
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Leski, Andrzej, Wojciech Wronicz, Piotr Kowalczyk, Michał Szmidt, Robert Klewicki, Karol Włodarczyk, and Grzegorz Uliński. "Modular Test Stand for Fatigue Testing of Aeronautical Structures – Verification of Assumptions." Fatigue of Aircraft Structures 2020, no. 12 (December 1, 2020): 78–91. http://dx.doi.org/10.2478/fas-2020-0008.
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Abstract The Modular Test Stand was developed and manufactured to decrease the cost of fatigue testing and reduce the time of its completion as well as to enable testing specimens under more complex load conditions. The stand consists of three connected sections, similar to a wing box, all being loaded in the same way. Thanks to that, several specimens can be tested simultaneously. This configuration requires that stress and strain distribution should be reasonably uniform, as assumed in the design stage. The structure can be loaded with bending or torsion. A whole section, selected structural node or a specimen mounted in the structure as well as a repair or a sensor can be a test object. Two stands, one for bending and one for torsion were prepared. This paper presents the verification of the assumed strain and stress distributions on the skin panels. The measurements were performed with the use of Digital Image Correlation (DIC) as well as strain gauges. DIC measurements were performed on one skin panel of the central section. Five strain gauge rosettes were installed on both panels of the one section. In addition, one rosette was applied to one skin panel in each of two other sections. Measurements were performed on the stand for torsion as well as on the stand for bending. The results of DIC analysis and strain gauge measurement during torsion show uniform shearing strain distributions on the panels. During bending, on the tensioned side, the strains obtained indicate quite uniform strain distributions. On the compressed side, local buckling of the skin panels results in high strain gradients. Strain levels obtained with the use of a DIC analysis and strain gauge measurements were similar. Moreover, horizontal displacements of markers in the spar axis during bending was determined based on a series of photographic. The deflection line obtained in this way has a shape similar to arc, which is characteristic of the constant bending moment. The stand was tested with torsional and bending loads in order to verify the design assumptions. The results of strain distributions on the skin panels with the use of DIC and strain gauges as well as the deflection line of the spar axis indicate that the Modular Test Stand performs as assumed and can be used for tests.
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Wichniarz, Marzena. "Certification of Testing Laboratories – The Basis of Reliability Among Research Vendors in Aviation." Fatigue of Aircraft Structures 2021, no. 13 (December 1, 2021): 99–105. http://dx.doi.org/10.2478/fas-2021-0009.
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Abstract Material characterization and assessment is a crucial stage in most of aviation and aeronautical research and a basis for further design and testing of more complex aircraft elements and structures. Material test’s reliability can only be guaranteed by conducting them at independent and reliable laboratories, operating based on a management system assessed by a third-party such as the accreditation according to the ISO / IEC 17025 or NADCAP or having the qualification of the second-party based on specific customer requirements. This paper introduces basic requirements for material testing laboratories according to accreditation systems and describes its responsibilities as qualified and reliable testing suppliers.
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Su, Yong Zhen, Xin Wen Liu, Da Yu Li, Xin Bing Wang, and Yu Heng Zhang. "Research on Impact Localization in Composite Materials Using Array Signal Processing and Lamb Wave." Advanced Materials Research 304 (July 2011): 65–72. http://dx.doi.org/10.4028/www.scientific.net/amr.304.65.
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Impact localization is one of the major concerns in maintenance of aircraft structures built from composites. A lot of different techniques like acoustic emission, optimization technique based on system are nowadays investigated to identify impact location. But the method to identify impact position in complex composite structure with high accuracy in real time has not been completely established. In the present work, a new efficient method is proposed for identifying impact location in real and complex composite structure based on array signal processing and Lamb waves. There are two steps in the proposed method. The first step is to estimate the direction- of-arrival (DOA) of impact source using continuous wavelet transform (CWT) and array signal processing; the second step is to estimate the distance between impact source and the coordinate origin based on propagation characteristic of Lamb wave and CWT. The composite panel with stepped thickness of a real and complex aeronautical tank is used to verify the present methodology. The result shows that the present method may identify impact location fast and accurately.
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IORDACHE, Valentin-Marian, and Casandra Venera PIETREANU. "Considerations on control processes in aeronautical organizations in the context of improving safety and efficiency." INCAS BULLETIN 11, no. 1 (March 5, 2019): 207–15. http://dx.doi.org/10.13111/2066-8201.2019.11.1.16.
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In modern aeronautical systems, one of the biggest challenges for the management structures is to maintain the control at all levels. Operational safety and efficiency impose the need to control all the associated risks and hazards; thus, in order to achieve organizational performance, a very important aspect is to establish and develop a strong organization with respect to operations and objectives. Nevertheless, performance cannot be achieved without control; the continuous technological development and the environmental variabilities have a great impact on the organizational management processes. Organizations are very complex and they will continue to expand due to the increasing demands of flight operations. The capacity to adapt, considering the permanent transformations in the society, represents a continuous process that needs to be carefully carried in order to diminish or eliminate the errors that may occur due to organizational factors. Controlling each operational step from the beginning represents the premises for obtaining stability and performance.
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Куэвас, Esmeralda Сuevas, Торрес, and Miguel Torres. "Advances in Aeronautical Nondestructive Inspection: New Methods and Configurable Robot-Based Solutions." NDT World 19, no. 4 (December 15, 2015): 33–35. http://dx.doi.org/10.12737/23502.
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The application of nondestructive testing to the aerospace sector is constantly improving, as fast as technology allows, due to increasing presence of composites in structures, the use of new materials and the new geometries emerging. This makes necessary to innovate in the development of NDT methods, like ultrasonics or thermography, and in particular in ultrasounds, from using conventional piezoelectric transducers to phased-array technology, that allows the generation of the sound beam easily controlled and configurable based on the use of a multi-elements matrix of probes that can be electronically trigger. Moreover, the application of popular UT techniques (pulse-echo and through transmission) has been extended to other new innovative techniques, such as laser ultrasonic and air coupled ultrasounds.
Tecnatom participates in different innovation project in NDT and develops new equipment for inspection of composite materials. One of the studies is in the comparison of different NDT methods and techniques for the inspection of cured and non-cured materials in aeronautical components with the help of air-coupled ultrasound and thermography.
In the article are described the use of robots in automated Tecnatom system, developed in cooperation with KUKA Robotics. The use of its own developed electronics, allow working efficiently with materials with high attenuation, and specialized software, allows effectively inspecting the complex geometries aviation parts, taking into account the scanning trajectory and robot movement and control all the inspection process.
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IORDACHE, Daniela-Monica, Eduard-Laurenţiu NITU, and Lia BOTILA. "Macroscopic and microscopic analysis of friction stir welding ofpolyethylene." University of Pitesti. Scientific Bulletin - Automotive Series 30, no. 1 (November 1, 2020): 1–6. http://dx.doi.org/10.26825/bup.ar.2020.006.
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The automotiveindustry is one of the most dynamic, advanced and innovative industries in Europe, being in constant search of solutions to reduce fuel consumption and pollutant emissions while maintaining or even improving the safety of passengers. One of the main directions in which the research of all car manufacturers is focused to reduce the weight of the car, through the increasing use of light metal alloys and polymeric materials. Polyethylene is one of the most widely used polymeric materials in the world, being widespread in many industries.The increasing use of this category of materials has led to the need to develop new reliable and efficient techniques for joining different materials to be used in complex structures. In the aeronautical and aerospace field, polymeric materials are used due to their low weight. The paper presents the macroscopic and microscopic analysis of the joining of these materials by FSW.
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Kaczyński, Paweł, Mariusz Ptak, Fábio A. O. Fernandes, Leszek Chybowski, Johannes Wilhelm, and Ricardo J. Alves de Sousa. "Development and Testing of Advanced Cork Composite Sandwiches for Energy-Absorbing Structures." Materials 12, no. 5 (February 27, 2019): 697. http://dx.doi.org/10.3390/ma12050697.
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Cork is a sustainable material with remarkable properties. In addition to its main application as wine stoppers, it has also been employed as a sound and thermal insulator in facades, building roofs, aeronautical applications, and, more recently, in impact energy absorption systems. In its natural form, cork is mainly used in wine stopper manufacturing, but for other applications, cork compounds are usually employed, which makes it possible to manufacture complex geometries with nearly isotropic behavior. In this work, an attempt was made to merge the desirable properties of two different cork materials (agglomerated and expanded black) into cork composite sandwich structures. These structures were tested according to impact conditions typically experienced by energy-absorbing liners used in personal safety devices. Additionally, the performance dependency on the working temperature was analyzed. The sole black, expanded cork (EC159) and agglomerated cork (AC199A and AC216) were tested in 500 J impacts. It was found that black cork was characterized by superior thermal stability, while expanded cork allowed absorbing high energies. In the second stage, the composites consisting of both tested materials were tested in 100 J impact scenarios. The combination of two materials of different properties enabled reduction of the peak force exerted on a helmet user’s head during the impact by about 10% compared to agglomerated specimens. Additionally, it was proved that there was no influence of the glue used to join different cork types.
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Zaharia, Sebastian Marian, Mihai Alin Pop, and Răzvan Udroiu. "Reliability and Lifetime Assessment of Glider Wing’s Composite Spar through Accelerated Fatigue Life Testing." Materials 13, no. 10 (May 17, 2020): 2310. http://dx.doi.org/10.3390/ma13102310.
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The evaluation of the reliability and the lifetime of aerospace components has become an important segment of the design stage. The aeronautical components are subjected to complex, rigorous tests and have a long test life. The main goal in the field of aviation is to have components with high reliability and quality and to meet the mandatory requirements and regulations. The spars are stiffening components positioned along the wing and which take up most of the load and are tested for fatigue over a long period of time. The spar which was analysed in this study has a sandwich structure with GFRP (glass fiber reinforced plastic) skin and foam core. In this paper, the performances in the static and dynamic conditions of the GFRP-foam sandwich structures cut out of the composite spar of a glider were analysed. Additionally, using accelerated techniques based on the three-point fatigue bending test, the main reliability indicators of the GFRP-foam sandwich structures were determined. Using the statistical processing of the experimental data and the Inverse Power Law–Weibull acceleration model, the mean number of cycles to failure, in normal testing conditions of the GFRP-foam specimens was determined, with a value of 102,814. Using the accelerated testing techniques of the GFRP-foam sandwich structures an important decrease of the test time (8.43 times) was obtained.
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Paulo, Rui Miguel Ferreira, Pierpaolo Carlone, Robertt A. F. Valente, Filipe Teixeira-Dias, and Gaetano S. Palazzo. "Integrated Design and Numerical Simulation of Stiffened Panels Including Friction Stir Welding Effects." Key Engineering Materials 554-557 (June 2013): 2237–42. http://dx.doi.org/10.4028/www.scientific.net/kem.554-557.2237.
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Stiffened panels are usually the basic structural building blocks of airplanes, vessels and other structures with high requirements of strength-to-weight ratio. They typically consist of a plate with equally spaced longitudinal stiffeners on one side, often with intermediate transverse stiffeners. Large aeronautical and naval parts are primarily designed based on their longitudinal compressive strength. The structural stability of such thin-walled structures, when subjected to compressive loads, is highly dependent on the buckling strength of the structure as a whole and of each structural member. In the present work, a number of modelling and numerical calculations, based on the Finite Element Method (FEM), is carried out in order to predict the ultimate load level when stiffened panels are subjected to compressive solicitations. The simulation models account not only for the elasto-plastic nonlinear behaviour, but also for the residual stresses, material properties modifications and geometrical distortions that arise from Friction Stir Welding (FSW) operations. To construct the model considering residual stresses, their distribution in FSW butt joints are obtained by means of a numerical-experimental procedure, namely the contour method, which allows for the evaluation of the normal residual stress distribution on a specimen section. FSW samples have been sectioned orthogonally to the welding line by wire electrical discharge machining (WEDM). Displacements of the relaxed surfaces are then recorded using a Coordinate Measuring Machine and processed in a MATLAB environment. Finally, the residual stress distribution is evaluated by means of an elastic FE model of the cut sample, using the measured and digitalized out-of-plane displacements as input nodal boundary conditions. With these considerations, the main goal of the present work will then be related to the evaluation of the effect of FSW operations, in the ultimate load of stiffened panels with complex cross-section shapes, by means of realist numerical simulation models.
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Zaimah, N., M. S. Hussain, and L. Masrur. "The Effects of Solution Movement to the Microstructure and Size of Nickel Plating on Titanium Surface by High Speed Direct Nanocrystalline Plating." Applied Mechanics and Materials 465-466 (December 2013): 867–71. http://dx.doi.org/10.4028/www.scientific.net/amm.465-466.867.
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Titanium has been widely used in many field of application due to the low density, sensitive to corrosion, high mechanical strength and ease of fabrication. It also has been widely used as structural materials in variety of industrial fields such as aeronautical, energy and chemical industry. Plating of metal on titanium is complex and difficult because titanium always reacts with air to form oxide. It is difficult to obtain good adhesive property on the titanium surface. Thus, to plate metal on the titanium, oxide layer must be eliminated by using an intermediate pre-treatment. However, this process involves several steps and even then the level of addition between the plated metal and the titanium is poor. This paper presents the results of the thickness and morphology of plated sample with the effects of the rate of deposition. The level adhesion of the nickel coating was determined qualitatively by using adhesion testing while morphology and thickness of Ni plated was studied using scanning electron microscopy (SEM) and field emissionscanning electron microscopy (FESEM). The results show by increasing the solution movement, it has been possible to obtain higher rate of plating and Ni deposits with higher hardness and finer grain structures. By using high speed electroplating and by maintaining a narrow gap between the anode and the cathode, it has been possible to electrodeposit Ni directly on Ti without any pre-treatment or even without any traditional cleaning before plating.
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Panteleev, A. V., and D. A. Rodionova. "APPLICATION OF HYBRID RANDOM SEARCH METHOD TO OPTIMISATION OF ENGINEERING SYSTEMS’ PARAMETERS." Civil Aviation High TECHNOLOGIES 21, no. 3 (July 3, 2018): 139–49. http://dx.doi.org/10.26467/2079-0619-2018-21-3-139-149.
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This paper presents a modification of the Luus-Jaakola global optimization method, which belongs to the class of metaheuristic algorithms. A hybrid method is suggested, using a combination of random search methods: Luus-Jaakola method, adaptive random search method and best trial method. The obtained method is applied to the optimization of parameters of different engineering systems. This class of problems appears during the design of aerospace and aeronautical structures; its goal is the cost or weight minimization of the construction. These problems belong to the class of constrained global optimization problems, where the level surface of the objective function has uneven relief and there is a large number of variables. This means that the classical optimization methods prove to be inefficient and these problems should be solved using metaheuristic optimization methods, which provide sufficient accuracy at reasonable operating time. In this paper, the constrained global optimization problem is solved using the penalty method. Thus, the problem of exterior penalty function optimization is considered, where the penalty coefficients are chosen in such a way as to avoid the violation of the constraints. Two applied problems are considered in the paper: the determination of the high-pressure vessel parameters and the anti rattle spring parameters determination. Using the suggested algorithm, a software complex was developed, which allows us to solve engineering optimization problems. The results obtained using the suggested methods were compared with the results obtained using the non-modified Luus-Jaakola method in order to demonstrate the efficiency of the suggested hybrid random search method.
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Cung, Long Thanh, Nam Hoang Nguyen, Pierre Yves Joubert, Eric Vourch, and Pascal Larzabal. "A model-based approach for inspection of aeronautical multi-layered structures by eddy currents." COMPEL - The international journal for computation and mathematics in electrical and electronic engineering 38, no. 1 (January 7, 2019): 382–94. http://dx.doi.org/10.1108/compel-02-2018-0102.
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Purpose The purpose of this paper is to propose an approach, which is easy to implement, for estimating the thickness of the air layer that may separate metallic parts in some aeronautical assemblies, by using the eddy current method. Design/methodology/approach Based on an experimental study of the coupling of a magnetic cup core coil sensor with a metallic layered structure (consisting of first metal layer/air layer/second metal layer), which is confirmed by finite element modelling simulations, an inversion technique relying on a polynomial forward model of the coupling is proposed to estimate the air layer thickness. The least squares and the nonnegative least squares algorithms are applied and analysed to obtain the estimation results. Findings The choice of an appropriate inversion technique to optimize the estimation results is dependent on the signal-to-noise ratio of measured data. The obtained estimation error is smaller than a few percent, for both simulated and experimental data. The proposed approach can be used to estimate both the air layer thickness and the second metal layer thickness simultaneously/separately. Originality/value This model-based approach is easy to implement and available to all types of eddy current sensors.
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Soll, Henning, Solveig Proske, Gesine Hofinger, and Gunnar Steinhardt. "Decision-Making Tools for Aeronautical Teams: FOR-DEC and Beyond." Aviation Psychology and Applied Human Factors 6, no. 2 (September 2016): 101–12. http://dx.doi.org/10.1027/2192-0923/a000099.
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Abstract. Many case studies show that unstructured decision-making processes in teams are contributing factors to accidents. In situations without any preconfigured solutions, airlines have developed decision models. In our article, we give an overview and comparative analysis of different models. We discuss FOR-DEC, developed by Lufthansa and the German Aerospace Center. Findings from an explorative study on pilots’ experiences with FOR-DEC and from a workshop with pilots and experts from non-aviation high-risk domains are reported. The model is useful for structured decision-making in complex situations when there is enough time. Moreover, some extensions to FOR-DEC could be beneficial, for example, the integration of expert knowledge into the decision process and the explicit integration of the team in the decision-making process. Results give advice for the useful implementation, application, and training of decision-making tools using the example of FOR-DEC.
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Wenner, Sigurd, Calin Daniel Marioara, Williams Lefebvre, Quentin M. Ramasse, Despoina Maria Kepaptsoglou, Fredrik S. Hage, and Randi Holmestad. "Atomic-Resolution Elemental Mapping of Precipitates in a 7449 Aluminium Alloy." Materials Science Forum 794-796 (June 2014): 63–67. http://dx.doi.org/10.4028/www.scientific.net/msf.794-796.63.
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The high-strength weldable 7xxxseries of aluminium alloys are of great importance to the aeronautics industry. Only recently, the complex structures of the AlZnMg hardening precipitates have been solved by HAADFSTEM imaging and first-principles calculations. However, perfect models of precipitate structures are often insufficient as several elements may be mixed into precipitate compositions. We have investigated this effect by STEMEELS spectrum imaging with an aberration-corrected microscope. In a 7449 alloy, Cu and Al were found to replace atoms at certain sites in both metastable and equilibrium ZnMg precipitates.
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Wu, Jiafeng, Rui Zhang, and Guangxin Yang. "Design and experiment verification of a new heavy friction-stir-weld robot for large-scale complex surface structures." Industrial Robot: An International Journal 42, no. 4 (June 15, 2015): 332–38. http://dx.doi.org/10.1108/ir-01-2015-0009.
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Purpose – This paper aims to present a new friction-stir-weld robot for large-scale complex surface structures, which has high stiffness and good flexibility. Design/methodology/approach – The robot system is designed according to manufacturability of large aluminum products in aeronautic and astronautic area. The kinematic model of the robot is established, and a welding trajectory planning method is also developed and verified by experiments. Findings – Experimental results show that the robot system can meet the requirements of friction stir welding (FSW) for large-scale complex surface structures. Practical implications – Compared with other heavy robotic arm and machine tool welding devices, this robot has better working quality and capability, which can greatly improve the manufacturability for large-scale complex surface structures. Originality/value – The friction-stir-weld robot system is a novel solution for welding large-scale complex surface structures. Its major advantages are the high stiffness, good flexibility and high precision of the robot body, which can meet the requirements of FSW. Besides, a welding trajectory planning method based on iterative closest point (ICP) algorithm is used for welding trajectory.
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Calabrese, Elisa, Pasquale Longo, Carlo Naddeo, Annaluisa Mariconda, Luigi Vertuccio, Marialuigia Raimondo, and Liberata Guadagno. "Design of self-healing catalysts for aircraft application." International Journal of Structural Integrity 9, no. 6 (December 3, 2018): 723–36. http://dx.doi.org/10.1108/ijsi-12-2017-0077.
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PurposeThe purpose of this paper is to highlight the relevant role of the stereochemistry of two Ruthenium catalysts on the self-healing efficiency of aeronautical resins.Design/methodology/approachHere, a very detailed evaluation on the stereochemistry of two new ruthenium catalysts evidences the crucial role of the spatial orientation of phenyl groups in the N-heterocyclic carbene ligands in determining the temperature range within the curing cycles is feasible without deactivating the self-healing mechanisms (ring-opening metathesis polymerization reactions) inside the thermosetting resin. The exceptional activity and thermal stability of the HG2MesPhSyncatalyst, with the syn orientation of phenyl groups, highlight the relevant potentiality and the future perspectives of this complex for the activation of the self-healing function in aeronautical resins.FindingsThe HG2MesPhSyncomplex, with the syn orientation of the phenyl groups, is able to activate metathesis reactions within the highly reactive environment of the epoxy thermosetting resins, cured up to 180°C, while the other stereoisomer, with the anti-orientation of the phenyl groups, does not preserve its catalytic activity in these conditions.Originality/valueIn this paper, a comparison between the self-healing functionality of two catalytic systems has been performed, using metathesis tests and FTIR spectroscopy. In the field of the design of catalytic systems for self-healing structural materials, a very relevant result has been found: a slight difference in the molecular stereochemistry plays a key role in the development of self-healing materials for aeronautical and aerospace applications.
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Rébillat, Marc, and Nazih Mechbal. "Damage localization in geometrically complex aeronautic structures using canonical polyadic decomposition of Lamb wave difference signal tensors." Structural Health Monitoring 19, no. 1 (April 24, 2019): 305–21. http://dx.doi.org/10.1177/1475921719843453.
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Monitoring in real time and autonomously the health state of aeronautic structures is referred to as structural health monitoring and is a process decomposed in four steps: damage detection, localization, classification, and quantification. In this work, the structures under study are aeronautic geometrically complex structures equipped with a bonded piezoelectric network. When interrogating such a structure, the resulting data lie along three dimensions (namely, the “actuator,”“sensor,” and “time” dimensions) and can thus be interpreted as three-way tensors. The fact that Lamb wave structural health monitoring–based data are naturally three-way tensors is here investigated for damage localization purpose. In this article, it is demonstrated that under classical assumptions regarding wave propagation, the canonical polyadic decomposition of rank 2 of the tensors build from the phase and amplitude of the difference signals between a healthy and damaged states provides direct access to the distances between the piezoelectric elements and damage. This property is used here to propose an original tensor-based damage localization algorithm. This algorithm is successfully validated on experimental data coming from a scale one part of an airplane nacelle (1.5 m in height for a semi circumference of 4 m) equipped with 30 piezoelectric elements and many stiffeners. Obtained results demonstrate that the tensor-based localization algorithm can locate a damage within this structure with an average precision of 10 cm and with a precision lower than 1 cm at best. In comparison with standard damage localization algorithms (delay-and-sum, reconstruction algorithm for probabilistic inspection of defects, and ellipse- or hyperbola-based algorithms), the proposed algorithm appears as more precise and robust on the investigated cases. Furthermore, it is important to notice that this algorithm only takes the raw signals as inputs and that no specific pre-processing steps or finely tuned external parameters are needed. This algorithm is thus very appealing as reliable and easy to settle damage localization timeliness with low false alarm rates are one of the key successes to shorten the gap between research and industrial deployment of structural health monitoring processes.
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Kellman, Philip J., and Mary K. Kaiser. "Perceptual Learning Modules in Flight Training." Proceedings of the Human Factors and Ergonomics Society Annual Meeting 38, no. 18 (October 1994): 1183–87. http://dx.doi.org/10.1177/154193129403801808.
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Differences between novices and experts in many piloting skills may be due to perceptual learning. Sufficient exposure to relevant stimulus variation produces more efficient information extraction, processing of higher-order patterns, and automaticity. Isolating and condensing relevant perceptual experience in part-task environments might accelerate training. Here we report initial studies of two prototype perceptual learning modules (PLMs) for flight training. Subjects were either experienced (500-2500 hour) civil aviators or non-pilots. In the Visual Navigation PLM, subjects received brief instruction on aeronautical chart symbology and then viewed 20-second segments of terrain (videotaped from aircraft). Each trial required a speeded, forced choice of the aircraft's location from three possible grid locations on the aeronautical chart. A separate control group received only 20 pre- and 20 post-test trials. In the Instrument Relationships PLM, subjects viewed displays of primary flight instruments and performed a speeded response classifying the flight attitude depicted. In both PLMs, subjects' speed and accuracy were measured over 9 blocks of trials. PLMs produced dramatic improvements in speed and accuracy for both non-pilots and pilots. Pilots initially outperformed non-pilots. Non-pilots after 1-2 hours of PLM training were as accurate and faster than pilots before training in both PLMs. The results suggest that PLMs have value for primary and recurrent training, both in aviation and other domains. Appropriately structured PLMs could condense perceptual learning processes that normally occur with extended experience. By fostering greater automaticity of pattern processing, PLMs might allow component skills to be more easily integrated in flight or other complex tasks.
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Leal, Malena Ley Bun, Barbara Bermudez-Reyes, Patricia del Carmen Zambrano Robledo, and Omar Lopez-Botello. "Parameter optimization of aluminum alloy thin structures obtained by Selective Laser Melting." MRS Advances 4, no. 55-56 (2019): 2997–3005. http://dx.doi.org/10.1557/adv.2019.434.
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ABSTRACTSelective Laser Melting (SLM) involves numerous fabrication parameters, the interaction between those parameters determine the final characteristics of the resulting part and because of the latter, it is considered a complex process. Low-density components is one of the main issues of the SLM process, due to the incorrect selection of process parameters. These defects are undesired in high specialized applications (i.e. aerospace, aeronautic and medical industries). Therefore, the characterization of the defects (pores) found in aluminum parts manufacture by SLM and the relationship with fabrication parameters was performed. A robust orthogonal design of experiments was implemented to determine process parameters, and then parts were manufactured in SLM. Relative density of the samples was then characterized using the Archimedes principle and microscopy; the data was then statistically analyzed in order to determine the optimal process parameters. The main purpose of the present research was to establish the best processing parameters of an in-house SLM system, as well as to characterize the pore geometry in order to fully eliminate pores in a future research.
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Lamari, Hajer, Amine Ammar, Adrien Leygue, and Francisco Chinesta. "First Steps on the Modeling and Simulation of Thermoplastic/Thermoset Phase Separation." Key Engineering Materials 504-506 (February 2012): 283–88. http://dx.doi.org/10.4028/www.scientific.net/kem.504-506.283.
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Matrices employed in composites parts of aeronautic structures consist of a thermoset / thermoplastic mixture. Thermoplastic is introduced in low concentration in order to improve the mechanical properties, in particular the ones related to choc resistance. However, there are two antagonist mechanisms, the one related to energy that leads to demixing and the one related to entropy that tends to mix. These effects are strongly coupled with the elasticity of thermoplastic, the evolution from a newtonian fluid to a viscoelastic one of thermosets, the presence of reinforcement fibers, … and are nowadays bad understood despite the significant impact that these effects have on the composite microstructure and then on its mechanical properties. This work constitutes a first attempt to understand these complex physics.
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Boțilă, Lia Nicoleta, Radu Cojocaru, and Victor Verbiţchi. "Ecological Joining Process of AZ31B Magnesium Alloy." Key Engineering Materials 890 (June 23, 2021): 76–81. http://dx.doi.org/10.4028/www.scientific.net/kem.890.76.
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Due to their properties (low density, high corrosion resistance, easy to process), magnesium alloys are used in all important industrial fields (aeronautics, automotive, transport, etc.). Magnesium is the lightest metal for complex metal structures with a density 2-3 times lower than that of aluminum and a quarter than that of steel. The possibility of joining magnesium with other materials allows a greater flexibility in designing and increasing the number of applications for light alloys.This paper presents results obtained by ISIM Timisoara for FSW welding of magnesium alloy AZ31B. Considering the difficulties that arise when welding magnesium alloys using classical processes, it can be assumed that by applying the FSW process for joining these types of materials, the results obtained are very good and can substantiate industrial applications.
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Venneri, Samuel L., and Ahmed K. Noor. "Plenty of Room in the Air." Mechanical Engineering 124, no. 11 (November 1, 2002): 42–48. http://dx.doi.org/10.1115/1.2002-nov-1.
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This article highlights a research on a spectrum of revolutionary concepts and technologies, for civilian and military air vehicles and the airspace system that will enable a bold new era of aviation and mobility. The long-range vision includes major changes in personal transportation and significant increases in air travel capacity and safety. The vision is included in the NASA Aeronautics Blueprint, published earlier this year. It includes advanced concepts for the airspace system as a complex, highly integrated system of systems. It also outlines a new model for aviation safety and security, revolutionary aerospace vehicles with significantly greater performance, and assured development of a competent aerospace workforce. NASA and the Defense Advanced Research Projects Agency are investigating the feasibility of creating personal air vehicles that could replace or, at the very least, augment personal ground and air transportation schemes. The integration of intelligence and multifunctionality into the varied airframe and propulsion components of aerospace vehicles requires the development of revolutionary materials, structures, and subsystems. They can be achieved through the fusion of nanotechnology, biotechnology, and information technology into a new discipline—nanobiologics—that is the foundation for biologically inspired materials and structures.
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Castellví, A., L. Poudelet, A. Tejo, L. Calvo, R. Uceda, P. Lustig, J. Minguella, et al. "The commissioning of a hybrid multi-material 3D printer." IOP Conference Series: Materials Science and Engineering 1193, no. 1 (October 1, 2021): 012044. http://dx.doi.org/10.1088/1757-899x/1193/1/012044.
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Abstract Additive Manufacturing (AM) has rapidly become an important technology in both research and industry. This development has allowed the evolution of 3D printers which are able to print complex geometries at low costs and faster than traditional methods. Despite this, most of these printers are either only for using one material or one technology. This limits a lot its use in different sectors such as aeronautics, automotive or health, because multi-material prototypes are needed. For example, surgeons need surgical planning prototypes for preoperative planning. These 3D printed prototypes have mainly been manufactured using just one technology. As a result, the prototypes have some main limitations: (1) do not actually mimic the anatomical structures of the human body, (2) high costs specially for Material Jetting and Powder Bed Fusion AM technologies. Therefore, the aim of present manuscript is the design, development, and commissioning of a hybrid multi-material 3D printer.
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Tokunaga, Roberto Abraham, Toru Hagiwara, Seiichi Kagaya, and Yuki Onodera. "Cellular Telephone Conversation While Driving: Effects on Driver Reaction Time and Subjective Mental Workload." Transportation Research Record: Journal of the Transportation Research Board 1724, no. 1 (January 2000): 1–6. http://dx.doi.org/10.3141/1724-01.
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The effects of conversation through a cellular telephone while driving on driver reaction time and subjective mental workload (SMWL) were investigated. Two vehicles equipped with measurement devices were used to measure reaction time. The drivers’ SMWL was measured by the National Aeronautics and Space Administration Task Load Index procedure. The experiment was conducted on an expressway in Japan. Thirty-one subjects participated in the experiment; 19 were young and 12 were elderly drivers. Each subject was asked to follow a leading vehicle and to keep a constant distance while following. The subjects performed four tasks: ( a) following a leading vehicle, ( b) operating a cellular telephone while following the leading vehicle, ( c) performing a simple conversation task, and ( d) performing a complex conversation task on a cellular telephone with the experimenter while following the leading vehicle. The results of these experiments indicated that the performance of the telephone tasks increases the reaction time and SMWL of the drivers, as was shown in a previous study. The results also indicated that the complex conversation task produced an increase in reaction time as compared to the simple conversation task, independent of age group. Furthermore, the experiment indicated that the SMWL also increased significantly in the complex conversation task as compared to the other tasks.
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Xie, Cihang, Ying Wu, and Zishun Liu. "Stress fields and effective modulus of piezoelectric fiber composite with arbitrary shaped inclusion under in-plane mechanical and anti-plane electric loadings." Mathematics and Mechanics of Solids 24, no. 10 (April 8, 2019): 3180–99. http://dx.doi.org/10.1177/1081286519840685.
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The piezoelectric fiber composite, which has been widely used in vibration control of aeronautic and aerospace structures, contains an active layer constructed by piezoceramic fibers embedded in polymer matrix. In this paper, an analytical framework is developed to predict the stress fields and the effective elastic and piezoelectric modulus of a piezoelectric fiber composite with arbitrary shaped inclusion under in-plane mechanical and anti-plane electric loadings. Firstly, a three-phase model is presented based on the general self-consistent method. It assumes that a representative volume element, consisting of an arbitrary shaped piezoelectric fiber and non-piezoelectric matrix, is embedded in infinite equivalent medium of piezoelectric fiber composite. Also, in order to obtain the complex potentials in different phases, a new conformal mapping method is proposed to translate two arbitrary connected domains into an annular domain. Then, the general solution of each complex potential can be expressed in series form with some coefficients. The continuity conditions of the interfaces and the homogeneous conditions are used to build up a set of equations to determine the coefficients. After the complex potentials are solved, the exact stress responses and effective modulus of piezoelectric fiber composite with arbitrary shaped inclusion are obtained. It is shown that the piezoelectric fiber shape and volume fraction have significant influence on the stress distributions around the piezoelectric fiber and effective modulus of the piezoelectric fiber composite. Furthermore, the proposed analytical framework provides a powerful instrument for solving related problems about fiber-reinforced composites with imperfect interface or with coated phase.
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Knittel, Dominique, Hamid Makich, and Mohammed Nouari. "Milling diagnosis using artificial intelligence approaches." Mechanics & Industry 20, no. 8 (2019): 809. http://dx.doi.org/10.1051/meca/2020053.
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The Industry 4.0 framework needs new intelligent approaches. Thus, the manufacturing industries more and more pay close attention to artificial intelligence (AI). For example, smart monitoring and diagnosis, real time evaluation and optimization of the whole production and raw materials management can be improved by using machine learning and big data tools. An accurate milling process implies a high quality of the obtained material surface (roughness, flatness). With the involvement of AI-based algorithms, milling process is expected to be more accurate during complex operations. In this work, a milling diagnosis using AI approaches has been developed for composite sandwich structures based on honeycomb core. The use of such material has grown considerably in recent years, especially in the aeronautic, aerospace, sporting and automotive industries. But the precise milling of such material presents many difficulties. The objective of this work is to develop a data-driven industrial surface quality diagnosis for the milling of honeycomb material, by using supervised machine learning methods. In this approach cutting forces are online measured in order to predict the resulting surface flatness. The developed diagnosis tool can also be applied to the milling of other materials (metal, polymer, etc.).
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Rodrigues, Luiz F. A., Fernando A. Amorim, Francisco F. R. Pereira, and Carlos J. de Araújo. "Experimental Study of Tungsten Inert Gas Pulsed Welding Applied to Ni-Ti Shape Memory Alloy Wires." MRS Proceedings 1765 (2015): 153–58. http://dx.doi.org/10.1557/opl.2015.822.
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ABSTRACTShape memory alloys are functional materials that can recover plastic strains between 2 and 6%. This property can be used to produce actuators for many areas as medicine, robotic, aeronautic and others. Recently, it has been observed the particular interest for shape memory alloys welding, especially to obtain Ni-Ti similar and dissimilar joints and fabricate simple or complex structures. In this sense, this work present an experimental study of tungsten inert gas pulsed welding applied to Ni-Ti shape memory alloy wires with 0.9 mm in diameter, previously heat treated at 450 °C for 20 minutes and air cooled. For that, it was carried out tensile tests at isothermal temperatures from 40 °C to 90 °C (steps of 10 °C) for welded and unwelded wires. The transformation temperatures obtained from differential scanning calorimetry were compared to verify the effect of welding process. It was also performed a stabilization process by mechanical cycling in some welded and unwelded Ni-Ti wires. The results showed a low strength and strain capacity of the weld joint at higher temperatures. Although, at lowest temperature, close to 40 °C, it was observed higher values of maximum stress and strain for welded Ni-Ti wires.
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Kumar, A., and J. N. Hefner. "Future challenges and opportunities in aerodynamics." Aeronautical Journal 104, no. 1038 (August 2000): 365–74. http://dx.doi.org/10.1017/s0001924000064009.
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Abstract Investments in aeronautics research and technology have declined substantially over the last decade, in part due to the perception that technologies required in aircraft design are fairly mature and readily available. This perception is being driven by the fact that aircraft configurations, particularly the transport aircraft, have evolved only incrementally over the last several decades. If, however, one considers that the growth in air travel is expected to triple in the next 20 years, it becomes quickly obvious that the evolutionary development of technologies is not going to meet the increased demands for safety, environmental compatibility, capacity, and economic viability. Instead, breakthrough technologies will be required both in traditional disciplines of aerodynamics, propulsion, structures, materials, controls and avionics as well as in the multidisciplinary integration of these technologies into the design of future aerospace vehicles concepts. The paper discusses challenges and opportunities in the field of aerodynamics over the next decade. Future technology advancements in aerodynamics will hinge on our ability to understand, model and control complex, three-dimensional, unsteady viscous flow across the speed range. This understanding is critical for developing innovative flow and noise control technologies and advanced design tools that will revolutionise future aerospace vehicle systems and concepts. Specifically, the paper focuses on advanced vehicle concepts, flow and noise control technologies, and advanced design and analysis tools.
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Matos, Nelson, Pedro Gamito, Margarida Pinto, Joel Ferreira, and Luis Oliveira. "Implementation of advanced technologies into Aeronautic integrated maintenance concept - Use of virtual reality in ground-floor training maintenance execution." MATEC Web of Conferences 304 (2019): 06002. http://dx.doi.org/10.1051/matecconf/201930406002.
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Aviation Maintenance industry, Repair and Overhaul (MRO) procedures need to keep up with the technological evolution and evolve from the 2D support to the 3D. The available manuals for learning and training MRO tasks rely much on old 2D drawings and lists of maintenance steps to be performed sequentially. However, these are complex actions that require and would benefit greatly from a 3D insight in order to be quickly and comprehensible absorbed. Virtual Reality (VR) apps are potentially a suitable option to turn these procedures closer to reality and, thus, improving competences and skills. Amongst the several maintenance optimization developments of the AIRMES project, which is cradled in the EU Clean Sky 2 Joint Undertaking programme, the above concept is applied to maintenance execution by developing a VR app to help practitioners in the process of carrying out specific maintenance activities as removing and positioning components into aircraft structures. The VR app runs on a mobile platform that uses a smartphone and a portable motion capture device coupled with a head mounted device allowing the practitioners to learn and to train onsite on how to proceed with the maintenance operations. The practitioners will be in an immersive and interactive environment where both the host aircraft structure section with the target component and auxiliary/peripheral systems parts are displayed and in which the 3D component can be removed by virtual hands that emulate, through the motion capture device, the hands of the user. The system developed provides a high-level training and reliable information to the technician on the maintenance operations for a dedicated situation and facilitate the identification and execution of the procedure to be applied, improving the time for repair.
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Nesterenko, K., S. Rahulin, and A. Sharabaiko. "HUMAN FACTOR IN THE QUALITY IMPROVEMENT SYSTEM OF AIRCRAFT MAINTENANCE." Системи управління, навігації та зв’язку. Збірник наукових праць 1, no. 59 (February 26, 2020): 41–44. http://dx.doi.org/10.26906/sunz.2020.1.041.
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The subject matter of the article is the analyzes of the human factor in the quality improvement system of maintenance markers, which are aimed to evaluate the completeness of amount of work completed by the responsible party and technology of work performance as provided for by an engineering order, the goal is compare the results of the work of various operators and teams with established standards or against each other, for justification of measures aimed at quality improvement, evaluation of these measures effectiveness. On the basis of the purpose of the quality indicators and the methods for their determination, there are distinguished – initial quality evaluation, composite quality measures and overall quality level. Each type of maintenance quality evaluation has corresponding fields of application and calculation procedure. The methods used are semi-Markov processes with a finite set of states, a generalized structured method, the use of game theory, construction and analysis of cause and effect graphs, and situation assessment tree graph. Results. Taking into consideration the constant complication of aviation technique (AT), by means of new technologies introduction, new requirements are being put forward for the ground support personnel, and as the result, the price for aircraft failure has risen. That’s why, the reduction of failures amount through the fault of maintenance personnel due to the psychological characteristics of their activities is among the priority tasks with regards to flight safety. This goes to prove that the influence of the human factor on the quality and effectiveness of aircraft maintenance has not been fully studied in world wide aeronautical science. Conclusions. In general, the problem of improving the quality of professional activities of maintenance operators is complex and research should concern the entire aspect of the factors affecting its performance
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Revilla, Reynier, Donovan Verkens, Tim Rubben, and Iris De Graeve. "Corrosion and Corrosion Protection of Additively Manufactured Aluminium Alloys—A Critical Review." Materials 13, no. 21 (October 28, 2020): 4804. http://dx.doi.org/10.3390/ma13214804.
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Metal additive manufacturing (MAM), also known as metal 3D printing, is a rapidly growing industry based on the fabrication of complex metal parts with improved functionalities. During MAM, metal parts are produced in a layer by layer fashion using 3D computer-aided design models. The advantages of using this technology include the reduction of materials waste, high efficiency for small production runs, near net shape manufacturing, ease of change or revision of versions of a product, support of lattice structures, and rapid prototyping. Numerous metals and alloys can nowadays be processed by additive manufacturing techniques. Among them, Al-based alloys are of great interest in the automotive and aeronautic industry due to their relatively high strength and stiffness to weight ratio, good wear and corrosion resistance, and recycling potential. The special conditions associated with the MAM processes are known to produce in these materials a fine microstructure with unique directional growth features far from equilibrium. This distinctive microstructure, together with other special features and microstructural defects originating from the additive manufacturing process, is known to greatly influence the corrosion behaviour of these materials. Several works have already been conducted in this direction. However, several issues concerning the corrosion and corrosion protection of these materials are still not well understood. This work reviews the main studies to date investigating the corrosion aspects of additively manufactured aluminium alloys. It also provides a summary and outlook of relevant directions to be explored in future research.
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Secco, Ney Rafael, and Bento Silva de Mattos. "Artificial neural networks to predict aerodynamic coefficients of transport airplanes." Aircraft Engineering and Aerospace Technology 89, no. 2 (March 6, 2017): 211–30. http://dx.doi.org/10.1108/aeat-05-2014-0069.
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Purpose Multidisciplinary design frameworks elaborated for aeronautical applications require considerable computational power that grows enormously with the utilization of higher fidelity tools to model aeronautical disciplines like aerodynamics, loads, flight dynamics, performance, structural analysis and others. Surrogate models are a good alternative to address properly and elegantly this issue. With regard to this issue, the purpose of this paper is the design and application of an artificial neural network to predict aerodynamic coefficients of transport airplanes. The neural network must be fed with calculations from computational fluid dynamic codes. The artificial neural network system that was then developed can predict lift and drag coefficients for wing-fuselage configurations with high accuracy. The input parameters for the neural network are the wing planform, airfoil geometry and flight condition. An aerodynamic database consisting of approximately 100,000 cases calculated with a full-potential code with computation of viscous effects was used for the neural network training, which is carried out with the back-propagation algorithm, the scaled gradient algorithm and the Nguyen–Wridow weight initialization. Networks with different numbers of neurons were evaluated to minimize the regression error. The neural network featuring the lowest regression error is able to reduce the computation time of the aerodynamic coefficients 4,000 times when compared with the computing time required by the full potential code. Regarding the drag coefficient, the average error of the neural network is of five drag counts only. The computation of the gradients of the neural network outputs in a scalable manner is possible by an adaptation of back-propagation algorithm. This enabled its use in an adjoint method, elaborated by the authors and used for an airplane optimization task. The results from that optimization were compared with similar tasks performed by calling the full potential code in another optimization application. The resulting geometry obtained with the aerodynamic coefficient predicted by the neural network is practically the same of that designed directly by the call of the full potential code. Design/methodology/approach The aerodynamic database required for the neural network training was generated with a full-potential multiblock-structured code. The training process used the back-propagation algorithm, the scaled-conjugate gradient algorithm and the Nguyen–Wridow weight initialization. Networks with different numbers of neurons were evaluated to minimize the regression error. Findings A suitable and efficient methodology to model aerodynamic coefficients based on artificial neural networks was obtained. This work also suggests appropriate sizes of artificial neural networks for this specific application. We demonstrated that these metamodels for airplane optimization tasks can be used without loss of fidelity and with great accuracy, as their local minima might be relatively close to the minima of the original design space defined by the call of computational fluid dynamics codes. Research limitations/implications The present work demonstrated the ability of a metamodel with artificial neural networks to capture the physics of transonic and subsonic flow over a wing-fuselage combination. The formulation that was used was the full potential equation. However, the present methodology can be extended to model more complex formulations such as the Euler and Navier–Stokes ones. Practical implications Optimum networks reduced the computation time for aerodynamic coefficient calculations by 4,000 times when compared with the full-potential code. The average absolute errors obtained were of 0.004 and 0.0005 for lift and drag coefficient prediction, respectively. Airplane configurations can be evaluated more quickly. Social implications If multidisciplinary optimization tasks for airplane design become more efficient, this means that more efficient airplanes (for instance less polluting airplanes) can be designed. This leads to a more sustainable aviation. Originality/value This research started in 2005 with a master thesis. It was steadily improved with more efficient artificial neural networks able to handle more complex airplane geometries. There is a single work using similar techniques found in a conference paper published in 2007. However, that paper focused on the application, i.e. providing very few details of the methodology to model aerodynamic coefficients.
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Astarita, Antonello, Silvio Genna, C. Leone, Fabrizio Memola Capece Minutolo, Valentino Paradiso, and Antonino Squillace. "Ti-6Al-4V Cutting by 100W Fibre Laser in Both CW and Modulated Regime." Key Engineering Materials 554-557 (June 2013): 1835–44. http://dx.doi.org/10.4028/www.scientific.net/kem.554-557.1835.
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Titanium and its alloys are nowadays widely used in many sectors: in the medical field (orthopedic and dental ones), in the architectural field, in the chemical plants field and in aeronautic [1]. In this last field it is more and more used both for its contribution to make lightweight and time durable structures and for its compatibility with new materials, first of all Carbon Fiber Reinforced Plastics (CFRP). Cutting of titanium sheets is one of the primary requirements in the fabrication of most of the components. Laser cutting offers several advantages over conventional cutting methods. It includes narrow kerf width (minimum material lost), straight cut edges, low roughness of cut surfaces, minimum metallurgical and surface distortions, easy integration with computer numerically controlled (CNC) machines for cutting complex profiles and importantly non-contact nature of the process (suitable for cutting in hostile environments and in areas with limited access) [2]. However, due to very limited literature available on laser cutting of titanium, it is very difficult to predict the cut surface quality and optimum process parameters for laser cutting, especially when dross-free cuts are required. Laser cutting of titanium and titanium alloys needs to be carried out with an inert gas, this due to the high reactivity of the titanium with the oxygen at high temperatures [3]. However when the available power is limited, as in the present case, the use of a reactive gas (air) can help to achieve cutting speed value reasonable for industrial applications. The aim of this work is to study the cutting of Ti-6Al-4V rolled sheets 1 mm in thickness, by means of a 100 W fibre laser, (SPI-Red Power) working at wavelength = 1090 nm. The maximum cutting speed were measured in both CW and pulsed regime at different mean power and different duration. Furthermore, the kerf geometry and the heat affected zone (HAZ) were studied decreasing the cutting speed from the maximum to the 80 % of this values. The results obtained showed that both the power and the cutting speed influence the cutting kerf geometry and HAZ. In particular the synergy of power and speed, resulting roughly into the heat input, seems to rule the whole cutting process.
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Tadimety, Amogha, M. Nabuan Naufer, Alison Burklund, David Luna, Timothy J. Palinski, Brian Vyhnalek, and Gary W. Hunter. "(Invited, Digital Presentation) Rational Design of Nanoplasmonic Array Geometries for Biosensing." ECS Meeting Abstracts MA2022-02, no. 61 (October 9, 2022): 2235. http://dx.doi.org/10.1149/ma2022-02612235mtgabs.
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Background: Molecular diagnostics provide early and accurate diagnosis, which is essential for the prevention and treatment of infectious as well as chronic diseases. These tests are designed to detect disease-specific bioanalytes such as nucleic acid (DNA or RNA) or protein (antigens, antibodies) biomarkers. In the context of infectious disease diagnosis, nucleic acid-based detection methods are known to provide more specific and sensitive results. Here, the presence of a unique sequence belonging to the pathogenic genomic material is targeted to identify species, organism, genera and/or antimicrobial resistant gene markers. The majority of the common nucleic acid based diagnostic techniques require amplification (polymerase chain reaction, isothermal amplification etc.) of the pathogenic genetic material prior to detection impacting diagnostic speed, complexity, and cost thereby limiting ease of use. Thus, the development of simplified nucleic acid-based diagnostics that can be even used in resource-poor settings may hugely benefit patients across the globe. Nanopath is a molecular diagnostics company utilizing a solid-state nanosensor to enable sequence-specific detection of target nucleic acids without the need of amplification. These nanostructures enable ultra-sensitive biomarker detection using geometric, feature-dependent properties highly dependent on the local dielectric environment, allowing them to be sensitive to low concentration binding events. This paper describes an application of this approach to provide highly relevant clinical information within a single doctor’s office visit. Introduction: The Nanopath team is in collaboration with NASA (National Aeronautics and Space Administration) and NIST (National Institute of Standards and Technology) to push the bounds of the fundamental physics associated with their biosensing platform. The ability of metals to support electromagnetic surface waves gives rise to surface plasmons when optically illuminated. This property, and its strong sensitivity to changes in the local refractive index, allows for the use of metal nanoparticles as ultra-sensitive transducers. In prior work by members of this team, ensembles of randomly oriented nanoparticles (i.e., colloidal nanorods dispersed on chip) were employed for sequence-specific nucleic acid sensing (1-3). While these particle sensors have the advantage of rapid fabrication, they suffer from low sensitivity and quality factor due to the random particle dispersity. In contrast, in this study we employ ordered array nanoparticle ensembles which can be used to improve sensor sensitivity and figure-of-merit. Study Methods Overview: In this talk, we detail the results of sensing experiments and computational simulations to outline a rational design of the structure of these plasmonic nanoparticle arrays for biomolecular sensing. Through simulation and experiment, we iteratively tailor nanostructure dimension to provide high quality signal and large resonance shifts upon modeled nucleic acid binding. In particular, full-wave electromagnetic simulations were conducted using Lumerical photonic simulation software in which periodic boundary conditions were applied in the x- and y- dimensions for each of the nanoplasmonic sensor geometries. To simulate the resonance response to changes in the bulk solution in contact with the sensor surface, the refractive index of the surrounding media was changed appropriately. Nucleic acid hybridization events were modeled using either using spherical structures approximating the relevant radius of genomic material as estimated by polymer models, or as conformal layers with the known refractive indices for nucleic acids. On the basis of initial simulations, nanosensors were fabricated using traditional electron-beam lithography protocols at NIST. To evaluate consensus between simulations and experiments, bulk sensing experiments were carried out in which the resonance peaks were obtained by submerging the sensors in refractive index standards. Key nanosensor characteristics including resonance peak locations, resonance peak shifts as a function of refractive index, and figure of merit (FOM) of extinction curves were examined between the experimental and simulation results prior to proceeding with simulations on additional geometries and more complex solution conditions, and further device fabrication. This iterative process is repeated toward a rational design of nanoplasmonic array geometries for biosensing optimizing response for targeted disease detection. In summary, this study puts forth a methodology for rational design and characterization of regularly spaced nanoparticle arrays for optics-based biosensing. The results of this study will allow for more informed design of nanostructure geometries towards sequence-specific nucleic acid detection. These improved designs have the potential to improve clinical sensitivity and limit-of-detection across disease indication. References: A. Tadimety, Y. Zhang, K.M. Kready, T.J. Palinski, G.J. Tsongalis, X.J. Zhang, Biosens. Bioelectron. 130 (2019) 236–244. A. Tadimety, Y. Zhang, G.J. Tsongalis, X.J. Zhang, S, J. Mol. Diagnostics. (2017) 915. https://doi.org/10.1016/S1525-1578(15)00191-9. A. Tadimety, Z. Wu, J.H. Molinski, R. Beckerman, C. Jin, L. Zhang, T.J. Palinski, J.X.J. Zhang, in: Proc. IEEE Sensors, Institute of Electrical and Electronics Engineers Inc., 2020.
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Guinard, Stéphane, Robin Bouclier, Mateus Toniolli, and Jean-Charles Passieux. "Multiscale analysis of complex aeronautical structures using robust non-intrusive coupling." Advanced Modeling and Simulation in Engineering Sciences 5, no. 1 (January 5, 2018). http://dx.doi.org/10.1186/s40323-017-0094-z.
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Abreu, C. C. E., F. R. Chavarette, F. Villarreal, M. A. Q. Duarte, and F. P. A. Lima. "DUAL-TREE COMPLEX WAVELET TRANSFORM APPLIED TO FAULT MONITORING AND IDENTIFICATION IN AERONAUTICAL STRUCTURES." International Journal of Pure and Apllied Mathematics 97, no. 1 (November 5, 2014). http://dx.doi.org/10.12732/ijpam.v97i1.9.
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Laporte, Théo. "Design, simulation and optimisation of lattice structures for remote control aeroplane." Journal of Intelligent Manufacturing and Special Equipment, December 23, 2021. http://dx.doi.org/10.1108/jimse-12-2020-0028.
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Purpose Thus, in this work the goal is to design, simulate and optimise a holder of a brushless motor in lattice structure to get the best performance in terms of mechanical strength, vibration absorption and lightness. Design/methodology/approach Nowadays, most manufacturers and designers' goal are to sell efficient products in mass to keep up or outrun competition. Medical, aeronautical, automobile and civil engineering sectors produce complex parts and products that encompasses multiple properties such as lightweight, energy absorbance, vibration reduction and stress resistant. Studies found that lattice structures are more and more useful in these fields since their characteristics satisfy complex behaviour. Findings The study's outcome suggests that the use of lattice structure reduces 60% of the actual motor holder mass while keeping the strength of the material, meeting initial specifications. Research limitations/implications The Ram capacity of the PC. Practical implications Light materials for aerospace engineering elongate the range of the unmanned aerial vehicle (UAV) to an extra range of flight. Social implications Situation awareness of the country border using surveillance drone and minimising the consumption of fuel. Originality/value The research allowed reducing 60% the actual holder mass.
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Ciminello, Monica, Bernardino Galasso, Gianvito Apuleo, Shay Shoam, and Antonio Concilio. "Local high edge observation for the bonding line monitoring of a complex composite beam." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, June 9, 2020, 095440622093219. http://dx.doi.org/10.1177/0954406220932194.
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The most part of defects in composite structures carrying attached subelements is the disbond at the interface, as the skin/stringer sections. This is sometimes due to a nonoptimal manufacturing process or sometimes due to accidental object impacts during service. It has been verified that structural discontinuities within an elastic medium under mechanical loads can cause analogous discontinuities within the strain field. Starting from this analysis, the present work investigates the effect of artificially induced kissing bond areas just at the in the skin–stiffener interface of an aeronautical complex composite beam. This research uses longitudinal strain values, acquired at the locations where distributed fiber optic sensors are installed. The applied methodology uses different strain-based features providing local high edge observation both in time and spatial domains. Their autocorrelations are, in the end, computed to improve signal-to-noise ratio. The local high edge observation algorithm is proposed that proves its capability to monitor disbond being at the same time load and baseline independent.
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Wang, Binwen, Xiangming Chen, Wenzhi Wang, Junchao Yang, and Ru Zhang. "Post-buckling failure analysis of composite stiffened panels considering the mode III fracture." Journal of Composite Materials, June 17, 2022, 002199832211099. http://dx.doi.org/10.1177/00219983221109946.
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Fully utilizing the post-buckling capacity of stiffened composite panels is important to reduce the weight of aeronautical composite structures. However, owing to the complex post-buckling failure modes and mechanisms, there are no effective analysis methods. This paper explores the impacts of the mode III fracture energy on the damage behavior of the stiffener–skin interface of composite stiffened panels under post-buckling conditions. To characterize the bonding interface damage, an interface damage initiation criterion considering the effects of through-thickness compression on the shear failure was used and combined with the Reeder damage extension criterion, which considers the mode III fracture. The mode III fracture toughness characteristics of the damage evolution of the stiffener–skin interface were obtained using the edge crack torsion (ECT) test method. Moreover, the compressive deformation response, buckling load, buckling modes, failure load, and failure modes of the panel were obtained by a compression test of I-shaped stiffened panels. Based on the aforementioned experimental data and numerical model, the post-buckling behavior of the I-shaped stiffened composite panels with an open cross-section stiffener was studied. It was found that the mode III fracture energy caused by the longitudinal shear stress τ31 played a major role in the stiffener–skin interface damage extension of the stiffened panels. Therefore, the mode III fracture behavior should not be ignored in the post-buckling analysis. The numerical analysis method developed can accurately predict the damage initiation and evolution processes of the composite panel interface. The method can be effectively used for post-buckling analysis of aeronautical composite panels.
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Yeswanth, IVS, Kanishk Jha, Shantanu Bhowmik, Rajeev Kumar, Shubham Sharma, and Ahmad Ilyas Rushdan. "Recent developments in RAM based MWCNT composite materials: A short review." Functional Composites and Structures, February 21, 2022. http://dx.doi.org/10.1088/2631-6331/ac5730.
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Abstract The need of developing Radar absorbing materials which meet the structural requirement of Defense applications is growing swiftly due to extensive use of electromagnetic (EM) waves in Radars. With major development and extensive use of Radar in military applications, the role of Radar absorbing structures with light weight and high strength has become prime objective for researcher working on development of Radar absorbing materials. Various composites are developed by using reinforcements which are dielectric such as CNT, Magnetic materials like Ferrites, have been extensively used as reinforcement in developing Radar absorbing materials. The ferromagnetic materials have high density and can achieve only narrow bandwidth absorption, CNT have very good electrical, mechanical and thermal properties and can achieve high dielectric losses but its complex synthesis process is a barrier in commercial applications. The research of reinforcing MWCNT with ferrites and metal oxides can also be extend to study thermoplastic polymers like PEEK and PAEK which is gaining prominence in aeronautical applications owing to its superior mechanical and low moisture absorbing properties. Further research can be done on the reinforcing metal oxides as metal oxides when reinforced with MWCNT proved to enhance the dielectric properties which improved the reflection losses as reported in a few studies.
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Vilar, M. M. S., D. A. Hadjiloizi, P. Khaneh Masjedi, and P. M. Weaver. "Stress recovery of laminated non-prismatic beams under layerwise traction and body forces." International Journal of Mechanics and Materials in Design, July 18, 2022. http://dx.doi.org/10.1007/s10999-022-09601-0.
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AbstractEmerging manufacturing technologies, including 3D printing and additive layer manufacturing, offer scope for making slender heterogeneous structures with complex geometry. Modern applications include tapered sandwich beams employed in the aeronautical industry, wind turbine blades and concrete beams used in construction. It is noteworthy that state-of-the-art closed form solutions for stresses are often excessively simple to be representative of real laminated tapered beams. For example, centroidal variation with respect to the neutral axis is neglected, and the transverse direct stress component is disregarded. Also, non-classical terms arise due to interactions between stiffness and external load distributions. Another drawback is that the external load is assumed to react uniformly through the cross-section in classical beam formulations, which is an inaccurate assumption for slender structures loaded on only a sub-section of the entire cross-section. To address these limitations, a simple and efficient yet accurate analytical stress recovery method is presented for laminated non-prismatic beams with arbitrary cross-sectional shapes under layerwise body forces and traction loads. Moreover, closed-form solutions are deduced for rectangular cross-sections. The proposed method invokes Cauchy stress equilibrium followed by implementing appropriate interfacial boundary conditions. The main novelties comprise the 2D transverse stress field recovery considering centroidal variation with respect to the neutral axis, application of layerwise external loads, and consideration of effects where stiffness and external load distributions differ. A state of plane stress under small linear-elastic strains is assumed, for cases where beam thickness taper is restricted to $$15^{\circ }$$ 15 ∘ . The model is validated by comparison with finite element analysis and relevant analytical formulations.
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Liu, Tianshu, Tao Chen, David Salazar, and Massimo Miozzi. "Skin friction and surface optical flow in viscous flows." Physics of Fluids, May 15, 2022. http://dx.doi.org/10.1063/5.0095416.
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The relationship between skin friction and the surface optical flow (SOF) in viscous flows is discussed based on the evolution equations of surface temperature, scalar and enstrophy where the SOF is defined as the convection velocity of these quantities. It is found that the SOF is proportional to skin friction, which can be determined by solving the optical flow equation re-cast from these evolution equations. This optical flow method can be applied to surface temperature and mass transfer visualizations to extract skin friction fields in experiments. To examine this method, it is first applied to complex surface enstrophy structures obtained in direct numerical simulation (DNS) data of a turbulent channel flow. Further, it is applied to surface temperature structures obtained in time-resolved temperature sensitive paint (TSP) measurements in a flow over a National Advisory Committee for Aeronautics (NACA) 0015 airfoil model and an impinging jet.
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Bayoumy, Ahmed H., Ayman A. Nada, and Said M. Megahed. "A Continuum Based Three-Dimensional Modeling of Wind Turbine Blades." Journal of Computational and Nonlinear Dynamics 8, no. 3 (October 30, 2012). http://dx.doi.org/10.1115/1.4007798.
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Accurate modeling of large wind turbine blades is an extremely challenging problem. This is due to their tremendous geometric complexity and the turbulent and unpredictable conditions in which they operate. In this paper, a continuum based three dimensional finite element model of an elastic wind turbine blade is derived using the absolute nodal coordinates formulation (ANCF). This formulation is very suitable for modeling of large-deformation, large-rotation structures like wind turbine blades. An efficient model of six thin plate elements is proposed for such blades with non-uniform, and twisted nature. Furthermore, a mapping procedure to construct the ANCF model of NACA (National Advisory Committee for Aeronautics) wind turbine blades airfoils is established to mesh the geometry of a real turbine blade. The complex shape of such blades is approximated using an absolute nodal coordinate thin plate element, to take the blades tapering and twist into account. Three numerical examples are presented to show the transient response of the wind turbine blades due to gravitational/aerodynamics forces. The simulation results are compared with those obtained using ANSYS code with a good agreement.
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Wu, Yanzhao, Ran Tao, Zhifeng Yao, Ruofu Xiao, and Fujun Wang. "Application and Comparison of Dynamic Mode Decomposition Methods in the Tip Leakage Cavitation of a Hydrofoil Case." Physics of Fluids, February 2, 2023. http://dx.doi.org/10.1063/5.0137411.
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The cavitation of tip leakage vortex (TLV) induced by tip leakage has always been a difficult problem faced by turbomachinery, its flow structure is complex and diverse. How to accurately extract the main structures that affect the cavitating flow of the TLV from the two-phase flow field is a key problem. In this study, the main mode extraction and low order mode reconstruction accuracy of the cavitation flow field of TLV downstream of National Advisory Committee for Aeronautics (NACA)0009 hydrofoil by two dynamic mode decomposition (DMD) methods are compared. The research shows that the main modes extracted by the standard DMD method contain a large number of noise modes, while the sparsity-promoting DMD (SPDMD) eliminates the noise modes, showing obvious advantages in the reconstruction accuracy of the velocity field. The characteristics of cavitation signals are analyzed, the cavitation signals are divided into four categories, which explains the reason why DMD methods have low reconstruction accuracy in cavitation. This study provides a theoretical basis and strong guarantee for the extraction of mode decomposition characteristics of two-phase flow field. This is of great significance for accelerating the prediction of multiphase flow field based on intelligent flow pattern learning in the future. Meanwhile, it also provides a new method and road for the introduction of artificial intelligence technology in the future scientific research.