Artykuły w czasopismach: „VIBRATORY LOADING”

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Lacoste, F. Rocher, i M. P. Bourdouxhe. "Behaviour of impact- and vibratory-driven piles in stiff clay during installation and static loading". Journal of Nepal Geological Society 34 (9.10.2006): 17–24. http://dx.doi.org/10.3126/jngs.v34i0.31874.

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This paper summarises the results of an extensive field test carried out in the framework of the "French National Research Project on Vibratory Driving" and the ProfilArbed Research Programme, to investigate and compare the behaviour and performance of eight impact- and vibratory-driven piles. The test site is located in Northern France. The subsoil consists of dense Flanders clay. The piles were driven using an ICE8 l5 vibrator and an IHC70s impact hammer to the same depth. All these piles were instrumented with accelerometers and strain gauges positioned at the top and bottom of the piles. Penetration rate, uplift load applied by the crane, vibration transmitted to the ground, operating pressure, oil flow at the vibratory power-pack, and energy per blow for the hammer were continuously recorded. The paper presents the main results obtained from double sheet piles (AUl6 type) driven to 7 m depth, a small wall of two double sheet piles (AU20 type) driven to 8 m depth, HP bearing piles driven to 10.2 m, and steel open-ended tubes of508 mm diameter driven to 9.4 m depth. After a delay of 6 to 8 weeks, the piles were statically loaded to failure. The piles were instrumented with removable extensometers, which made it possible to measure the mobilisation of shaft friction and toe resistance. The measured bearing capacity was significantly lower for the vibratory-driven piles (around 35%) and it is consistent with the results obtained by the Laboratoire des Ponts et Chaussees de Paris at other sites.

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Wang, Jijing, i Zhihua Tan. "Mechanical and Mesoscale Analyses of Cement Stabilized Macadam Prepared by Vibratory and Nonvibratory Mixing Techniques". Advances in Civil Engineering 2021 (9.02.2021): 1–13. http://dx.doi.org/10.1155/2021/6663233.

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The objective of this study is to analyze the effects of mixing techniques on the mechanical behavior and meso-structure of cement-treated aggregate. Different specimens were prepared by vibratory and nonvibratory mixing techniques. X-ray CT scans were performed to illustrate the distribution of cement mortar on aggregate. The strength, modulus, and fatigue tests under different stress states were tested to reveal the impacts of mixing techniques. Then, the relationships between strengths and loading rates and that between moduli and stress levels were established. Hereafter, the S-N fatigue equation that modified with stress ratio related to loading rates was used to describe the fatigue performance. The results indicate that the cement mortar of specimens prepared by vibratory mixing was well-distributed on aggregates. The strength, modulus, and fatigue life of the specimens prepared by vibratory mixing were higher under the test condition threshold. Moreover, the growth rate of strength and modulus with loading for specimens prepared by vibratory mixing was slightly larger than that for specimens prepared by nonvibratory mixing. Compared with the cement-treated aggregates specimens prepared by nonvibratory mixing, the fatigue life of cement-treated aggregates specimens prepared by vibratory mixing had more stable stress sensitivity.

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Nadutyi, V. P., i E. C. Lapshin. "Probabilistic simulation of vibratory screening under high loading conditions". Refractories and Industrial Ceramics 45, nr 6 (listopad 2004): 453–56. http://dx.doi.org/10.1007/s11148-005-0033-2.

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de Montaudouin, J., N. Reveles i M. J. Smith. "Computational aeroelastic analysis of slowed rotors at high advance ratios". Aeronautical Journal 118, nr 1201 (marzec 2014): 297–313. http://dx.doi.org/10.1017/s0001924000009131.

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Abstract The aerodynamic and aeroelastic behaviour of a rotor become more complex as advance ratios increase to achieve high-speed forward fight. As the rotor blades encounter large regions of cross and reverse flows during each revolution, strong variations in the local Mach regime are encountered, inducing complex elastic blade deformations. In addition, the wake system may remain in the vicinity of the rotor, adding complexity to the blade loading. The aeroelastic behaviour of a model rotor with advance ratios ranging from 0·5 to 2·0 has been evaluated with aerodynamics provided via a computational fluid dynamics (CFD) method. Significant radial blade-vortex interaction can occur at a high advance ratio; the advance ratio at which this occurs is dependent on the rotor configuration. This condition is accompanied by high vibratory loads, peak negative torsion, and peak torsion and in-plane loads. The high vibratory loading increases the sensitivity of the trim model, so that at some high advance ratios the vibratory loads must be filtered to achieve a trimmed state.

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Dyrda, Vitalii, Anatolii Kobets, Viktor Pukhalskyi, Yurii Kozub i Oleksandr Chernii. "Dynamics of vibratory partitioned feeders for the uranium ore drawing and feeding". E3S Web of Conferences 109 (2019): 00023. http://dx.doi.org/10.1051/e3sconf/201910900023.

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In this paper, the authors consider dynamics of partitioned vibratory feeders with rubber elastic couplings. Use of vibratory feeders (including partitioned ones) and schemes for the ore vibrating drawing, feeding and loading in underground conditions allowed to mechanize one of the most time-consuming and dangerous processes of uranium ore mining and to solve the following problems: to improve effectiveness of the lumpy rock mass drawing and loading by 2.5-3 times; to increase intensity of mining operations and reduce life of the excavation blocks and horizons; to reduce labor intensity and cut cost of the process of ore drawing and loading; to improve uniformity of the rock-mass outflowing from the discharge opening and to reduce by 3-5 times frequency of the large-lump material freezing (use of partitioned feeders reduces number of freezes by 25-60 times); to increase size of commercial lump panels; practically to exclude traumas during the process of ore drawing and loading (usually, it presents 30-60 % of all traumas caused by the underground operations); to mechanize process of ore drawing and loading, and to create conditions for implementation of low-waste cyclic-and-continuous mining technology.

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Gu, Li Zhi, i T. Lee. "Dynamic Stress Intensity Factor with Griffith – II Type Crack in Vibratory Machining and its Influence on Chip Formation". Applied Mechanics and Materials 10-12 (grudzień 2007): 939–44. http://dx.doi.org/10.4028/www.scientific.net/amm.10-12.939.

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Reviewed the achievements and advances in the vibratory metal machining, analyzed the features and mechanics in microstructure with SEM. The dynamic stress intensity factor is derived on the basis of fracture mechanics and stress-wave theory with the Griffith- II type sliding-open crack.. Comparison between the vibratory machining and the conventional machining has been made with brass on lathe CW6150B, with computer controlled piezoelectric ceramic micro-drive system and cutting forces and surface texture of the specimen were observed. The dynamic stress intensity factor was discussed and it was found that the value of dynamic stress intensity factor may be high with response to the Heaviside impulsive loading, indicating the reason why vibratory machining has better comprehensive results than the conventional one does.

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David Suits, L., TC Sheahan, MA Mooney i CO Bouton. "Vibratory Plate Loading of Compacted and Instrumented Field Soil Beds". Geotechnical Testing Journal 28, nr 3 (2005): 12448. http://dx.doi.org/10.1520/gtj12448.

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Sobczyk, Kazimierz, Kyriakos Perros i Costas Papadimitriou. "Fatigue Reliability of Multidimensional Vibratory Degrading Systems under Random Loading". Journal of Engineering Mechanics 136, nr 2 (luty 2010): 179–88. http://dx.doi.org/10.1061/(asce)em.1943-7889.0000052.

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Bespalov, A. L., I. G. Svidrak i O. O. Boiko. "Improving the performance of vibration feeders with an electromagnetic vibration drive and a combined vibration system". Scientific Messenger of LNU of Veterinary Medicine and Biotechnologies 22, nr 93 (13.05.2020): 26–30. http://dx.doi.org/10.32718/nvlvet-f9305.

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Vibration loading devices are widely used in various branches of mechanical engineering to load piece blanks of automatic machines and automatic lines as well as robotic systems, automated systems and flexible automated production. Vibration devices for transportation and loading of miniature, small and medium-sized products are the most widely used. Modern designs of vibratory feeders, made according to the classical dynamic scheme and having a two-mass oscillating system, do not fully use the energy of the vibratory exciter to perform useful work. In addition, due to the presence of a heavy reactive mass, they have a fairly large weight. When the vibrating feeder is operating, the energy of the vibration exciter is spent on pumping both the hopper, which performs useful work, and the reactive plate, which performs idle vibrations. Thus, part of the energy of the vibration exciter is not used for performing useful work, but is spent idly. To increase the efficiency of the device, increase its performance and reduce its weight and metal consumption, it is necessary to change the design of the vibratory feeder and some of its elements, which affect the redistribution of the oscillation amplitudes of the working (hopper) and reactive mass of the vibratory feeder. Modern production involves the creation of new models of machines with high technical and economic indicators, therefore, improving the efficiency of existing equipment and the development of new schemes of machines is an important task for designers and manufacturers of technological equipment, as the minimum improvement of its technological and operational performance can lead to a tangible economic effect. To solve this problem we developed a new design vibrating hopper feeder, in which the increase of the horizontal component of the oscillation amplitude of the working element (hopper) is not at the expense of increased power of the vibratory exciter, but due to internal redistribution of energy between the elements of the oscillating system that makes better use of the energy of the vibratory exciter to perform useful work, i.e. to increase the coefficient of useful action. In addition, the weight and metal content of the vibrating feeder structure are simultaneously reduced.

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Yamazaki, Satoru, Paul S. Weinhold, Ronald D. Graff, Mari Tsuzaki, Mamoru Kawakami, Joe T. Minchew i Albert J. Banes. "Annulus cells release ATP in response to vibratory loading in vitro". Journal of Cellular Biochemistry 90, nr 4 (24.10.2003): 812–18. http://dx.doi.org/10.1002/jcb.10681.

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Sharma, Tanushree, Ankita Gupta, Aseem Sharma, Pulkit Vaid, Kamlesh Singh i Chahat Puri. "Cyclic loading; its impact on the orthodontic tooth movement in growing patients: in vivo study". International Journal of Scientific Reports 8, nr 1 (24.12.2021): 1. http://dx.doi.org/10.18203/issn.2454-2156.intjscirep20214931.

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Background: The objective of the study was to evaluate the impact of vibratory stimulation on the orthodontic tooth movement rate in growing patients and to compare the orthodontic tooth movement rate in experimental and control sides.Methods: Split-mouth design study was done on 30 growing fixed appliance therapy orthodontic cases with bilateral first premolar extractions in maxillary arch. Individual canine retractions were performed in all the subjects with type-1 active tiebacks. Oral-B powered toothbrushes (125 Hz) were used to provide vibratory stimulation for 15 minutes per day (splits into 5 minutes thrice a day). The tooth movement was measured with calibrated digital vernier caliper clinically at various time intervals (T0, T1 and T2). OPG were taken at regular mentioned time intervals and grid method was used to calculate the tooth movement on OPGs.Results: Results were evaluated statistically and the p-value revealed significantly increased rate of tooth movement on experimental side as compared to control side.Conclusions: The high-frequency vibratory stimulation along with fixed orthodontic appliance can reduce treatment time expeditiously in growing patients. Powered toothbrushes can use successfully for providing vibrations to enhance the rate of tooth movement.

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Ter-Martirosyan, Armen Z., Alexander N. Shebunyaev i Vitalii V. Sidorov. "Mathematical Analysis of the Vibratory Pile Driving Rate". Axioms 12, nr 7 (26.06.2023): 629. http://dx.doi.org/10.3390/axioms12070629.

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Vibratory piling technology does not require analytical tools to predict displacement rates and arising forces. The authors consider the problem of vibratory driving of a pile into a homogeneous unsaturated sandy massif under the action of static and dynamic loads. The purpose of this study is to develop a new analytical solution to the problem of the vibratory pile driving rate in a homogeneous sand base taking vibration creep into account. The solution is provided for the quasi-dynamic problem statement (inertial terms in equations of motion are neglected): the sand medium develops viscous properties due to vibration under the action of the dynamic component of the load, and a pile is driven into the viscous sand base due to the static component of the vertical load. The obtained mathematical model converges with the results of laboratory flume and field experiments performed by other researchers earlier, where the pile vibratory embedding rate increased along with an increase in static loading, the amplitude of dynamic load, and vibration frequency. It can be used to predict the pile or sheet pile driving rate into the unsaturated sand base under the action of vibration, and also to evaluate the necessary parameters of pile driving to obtain the required value of the pile embedding rate.

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Walls, D. P., R. E. deLaneuville i S. E. Cunningham. "Damage Tolerance Based Life Prediction in Gas Turbine Engine Blades Under Vibratory High Cycle Fatigue". Journal of Engineering for Gas Turbines and Power 119, nr 1 (1.01.1997): 143–46. http://dx.doi.org/10.1115/1.2815538.

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A novel fracture mechanics approach has been used to predict crack propagation lives in gas turbine engine blades subjected to vibratory high cycle fatigue (HCF). The vibratory loading included both a resonant mode and a nonresonant mode, with one blade subjected to only the nonresonant mode and another blade to both modes. A life prediction algorithm was utilized to predict HCF propagation lives for each case. The life prediction system incorporates a boundary integral element (BIE) derived hybrid stress intensity solution, which accounts for the transition from a surface crack to corner crack to edge crack. It also includes a derivation of threshold crack length from threshold stress intensity factors to give crack size limits for no propagation. The stress intensity solution was calibrated for crack aspect ratios measured directly from the fracture surfaces. The model demonstrates the ability to correlate predicted missions to failure with values deduced from fractographic analysis. This analysis helps to validate the use of fracture mechanics approaches for assessing damage tolerance in gas turbine engine components subjected to combined steady and vibratory stresses.

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Bondar, R. P. "Determination of Loading Equivalent Parameters of the Linear Permanent Magnet Vibratory Machine". Visnyk of Vinnytsia Politechnical Institute 146, nr 5 (2019): 21–27. http://dx.doi.org/10.31649/1997-9266-2019-146-5-21-27.

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KONDO, Yoshiyuki, Chu SAKAE, Masanobu KUBOTA i Hiroki KITAHARA. "Fatigue under Mixed Mode Loading of Vibratory Stress and Start-Stop Cycling". Journal of the Society of Materials Science, Japan 53, nr 10 (2004): 1130–35. http://dx.doi.org/10.2472/jsms.53.1130.

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Bondar, R. "OPERATING CHARACTERISTICS OF THE LINEAR PERMANENT MAGNET VIBRATORY MOTOR WITH VISCOELASTIC LOADING". Electromechanical and energy saving systems 3, nr 47 (31.10.2019): 48–56. http://dx.doi.org/10.30929/2072-2052.2019.3.47.48-56.

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Kubotsch, Marcel, Rudi Scheck, Dieter Willer, Magdalena Speicher i Ewa Anna Soppa. "Impact of surface preparation on the formation of deformation-induced α‘-martensite in a metastable austenitic steel". Practical Metallography 59, nr 2 (1.02.2022): 75–91. http://dx.doi.org/10.1515/pm-2022-0008.

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Abstract The metastable austenitic steel X6CrNi-Nb18-10 (AISI 347) will partly transform to α‘-martensite under mechanical loading at room temperature. In order to determine the influence of loading conditions on deformation-induced martensitic transformation, a thorough surface preparation is required for the samples to be analyzed, ensuring that a martensite-free sample surface is achieved prior to mechanical loading. In this paper, two preparation techniques were compared, focusing in particular on the final preparation step, which is polishing. Measurements using electron backscatter diffraction (EBSD) have revealed that large α‘-martensite volume fractions of more than 20 % are present on the prepared sample surface after vibratory polishing. However, they can be removed almost completely by electrolytic polishing and chemical etching respectively.

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Homma, Kenji, Paul R. Braunwart i Patrick L. Clavette. "Assessment of digital image correlation vibrometry in the presence of thermal flow disturbance". INTER-NOISE and NOISE-CON Congress and Conference Proceedings 263, nr 3 (1.08.2021): 3861–70. http://dx.doi.org/10.3397/in-2021-2543.

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Digital Image Correlation (DIC) is an image-based method for measuring displacement and/or stain on the surface of a structure. When coupled with a stereo pair of highspeed cameras, DIC can also capture three-dimensional dynamic deformation of a structure under vibratory loading. However, high frequency and small amplitude displacement typically associated with structural vibrations mean that extra care is required during measurement and data processing. It becomes more challenging when thermal disturbances are present in the optical path, for example from a heated air flow, which introduces extraneous noise due to disturbances in the refractive index. In the present study, a simple composite plate was vibrated under a shaker excitation and stereo DIC measurements were performed. The obtained vibratory displacement results were compared against accelerometers and a laser Doppler vibrometer. Heated air flow was introduced in front of the plate to observe the effects of thermal disturbances on the DIC measurements. Although the contributions from the thermal disturbances were clearly visible in the DIC displacement data, it was shown that the vibratory deflections of the structure could still be extracted by post processing of the DIC data.

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Kachur, Oleksandr, Vitaliy Korendiy, Oleksii Lanets, Roman Kachmar, Ihor Nazar i Volodymyr Heletiy. "Dynamics of a vibratory screening conveyor equipped with a controllable centrifugal exciter". Vibroengineering PROCEDIA 48 (11.02.2023): 8–14. http://dx.doi.org/10.21595/vp.2023.23175.

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Vibratory screening, sieving, and conveying processes are widely used in various industries. Among a great variety of vibration exciters, the unbalanced rotors are the most reliable, simple, and widespread ones. Due to the changeable operating conditions of vibratory equipment, in some cases, there occurs a necessity to control the disturbance (excitation) parameters of the corresponding drives. The primary purpose of this study is to substantiate the design parameters and analyze the dynamic characteristics of the vibratory screening conveyor based on the single-mass oscillatory system, and equipped with the controllable centrifugal exciter. The research methodology consists of several basic stages: developing the conveyor’s dynamic diagram and deducing the differential equations of the system’s motion; designing the machine’s 3D-model and defining its main geometrical and inertial parameters; numerical modeling of the system’s oscillations in the Mathematica software; simulating the conveyor’s operation in the SolidWorks software. The research results present the time dependencies of the conveyor’s working member kinematic parameters at different eccentricities of the unbalanced mass. The main scientific novelty of this research is substantiating the idea and possibilities of implementing the enhanced controllable centrifugal exciter for changing the disturbance (excitation) conditions of the vibratory screening and conveying machines. The proposed ideas and obtained results can be used by researchers and designers of similar equipment while developing control systems for regulating its operational efficiency (performance) in accordance with the changeable loading conditions or technological requirements.

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Tyuremnov, I. S., i S. S. Efimov. "SIMULATION OF VIBRATORY PLATE INTERACTION WITH THE GROUND SURFACE". PNRPU Mechanics Bulletin, nr 4 (15.12.2022): 30–41. http://dx.doi.org/10.15593/perm.mech/2022.4.04.

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The paper presents a three-mass rheological model of the system "soil – vibration plate base – vibration plate frame". The rheological model makes it possible to reproduce different modes of interaction between the vibratory plate base and soil: with different types of plate decoupling and without decoupling. We verify this model by comparing the experimental values of the vertical oscillation span of the base and frame of the Zitrek CNP 20 vibrating plate with the previously calculated values. As a whole, the calculated values of the span of vertical oscillations of the base and frame of the Zitrek CNP 20 vibrating plate correlate with the experimental data in the range of the dynamic modulus of soil deformation of 13…30 MPa. During the experiment we used the rheological model and obtained results are as follows: the mass of the vibrating plate (50; 150; 250; 350; 450; 550; 650; 750 kg), the coefficient of the elastic resistance of soil (30; 60; 90; 120 MN / m), and the coefficient of viscous resistance of soil (100; 200; 300 kN • s / m). The total number of combinations of parameters was 96. The processed results of the computational experiment provide the regression dependences for calculating the maximum soil reaction force, the time of soil loading (increasing the values of the reaction force of soil) t1, and the time of soil unloading (decrease the values of the reaction force of soil) t2. The simulation results show that, within one exposure cycle, the soil loading time t1 is less than the soil unloading time t2. The ratio t1/t2 is influenced by the weight of the vibratory plate, as well as the factors of elastic and viscous resistance of soil. This feature (t1/ t2  1) is typical for both vibratory rollers and rammers, which is confirmed by the results of the relevant experimental studies. The obtained regression dependences of parameters Fs, t1, and t2 on the vibratory plate mass and the factors of elastic and viscous resistance of soil are important for calculating the distribution of stresses and strains on the depth of the compacted soil.

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Svietkina, Olena, Kostiantyn Bas, Fadi Alfaqs, Kyrylo Ziborov i Valery Fedoskin. "Mechanochemical Activation of Materials to Produce Conductive and Superconductive Substances for Batteries". Solid State Phenomena 291 (maj 2019): 121–30. http://dx.doi.org/10.4028/www.scientific.net/ssp.291.121.

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It has been demonstrated that vibratory impact mineral loading results in the formation of solid solutions. A technique to determine concentration dependence of inversion degree of solid binary solutions according to the known values of their components activity has been proposed. Values of thermodynamic functions of the solutions mixing in terms of statistic formulas as well as by means of immediate processing of the experiment have been determined.

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Dickerson, D. A., E. A. Sander i E. A. Nauman. "Modeling the mechanical consequences of vibratory loading in the vertebral body: microscale effects". Biomechanics and Modeling in Mechanobiology 7, nr 3 (23.05.2007): 191–202. http://dx.doi.org/10.1007/s10237-007-0085-y.

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Eisinger, Frantisek L., i Robert E. Sullivan. "Vibration Fatigue of Centrifugal Fan Impeller Due to Structural-Acoustic Coupling and Its Prevention: A Case Study". Journal of Pressure Vessel Technology 129, nr 4 (25.10.2006): 771–74. http://dx.doi.org/10.1115/1.2767371.

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Fatigue cracks from high cycle vibratory loading have developed in a centrifugal fan impeller after a relatively short period of operation. Based on vibration tests of the impeller and acoustic analysis of the internal spaces of the fan, structural-acoustic coupling with matching frequencies involving two-nodal diameter modes (structural and acoustic) was identified as the cause of the vibration problem. This paper gives a description of the problem and identifies available remedies for its elimination. Special attention is given in Case 1 to the acoustics of the system, where changes to the fan casing utilizing a decoupling acoustic chamber attached to the casing was investigated, and in Case 2, where changes needed to the structural characteristics of the impeller by utilizing a modified impeller with a substantially increased natural frequency (by 44%) of the two-nodal diameter vibratory mode shape were studied. Experimental tests confirmed that the structural-acoustic coupling and vibration were significantly reduced in Case 1 and were fully eliminated in Case 2.

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Dyrda, V. I., M. I. Lysytsia, V. A. Lapin, H. M. Ahaltsov, Ye V. Kalhankov, O. V. Tolstenko i O. A. Chernii. "DYNAMICS OF HEAVY VIBRATING MACHINES TAKING INTO ACCOUNT INSTABILITY IN TIME OF THEIR PARAMETERS". NEWS of National Academy of Sciences of the Republic of Kazakhstan 6, nr 444 (15.12.2020): 68–74. http://dx.doi.org/10.32014/2020.2518-170x.132.

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Underground mining of uranium ores consists of several technological processes, one of the most important of which is the release of broken rock from the working excavation zone and loading it into transportation vehicles. The issue of increasing the intensity of production requires a simultaneous increase in the productivity of all production processes, including the production of mineral raw materials. At the same time, it is necessary to create both a high-performance and a safe process. This problem is successfully solved by the use of vibration machines with elastic links made of elastomeric materials, which, along with an increase in productivity, can reduce energy consumption and the number of freezes. An integrated approach was used, which includes analytical studies and results of industrial tests of vibratory feeders for underground mining and delivery of uranium ores and building materials. On the basis of the developed algorithm and synergistic model of fatigue microfracture of rubber links in vibratory feeder, mathematical equations were obtained, which made it possible to describe dynamics of feeders with time-depending parameters; when solving the integro-differential equation of the oscillatory system, the dependence of the amplitude characteristics of the feeder on the time of its operation is obtained. An original algorithm and synergistic model were developed, and on their basis, a mathematical apparatus was created, which allowed determining change of amplitude of vibratory feeder oscillations during its operation. On the basis of analytical calculations, a method was developed and introduced for predicting changes of parameters change of oscillation amplitudes of vibratory feeder used for underground mining and feeding of uranium ores.

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Yamazaki, Satoru, Albert J. Banes, Paul S. Weinhold, Mari Tsuzaki, Mamoru Kawakami i Joe T. Minchew. "Vibratory loading decreases extracellular matrix and matrix metalloproteinase gene expression in rabbit annulus cells". Spine Journal 2, nr 6 (listopad 2002): 415–20. http://dx.doi.org/10.1016/s1529-9430(02)00427-8.

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HATTORI, Yasuhisa. "3037 Dynamic Friction Characteristics of Paper-Based Wet Friction Material Subjected to Vibratory Loading". Proceedings of the JSME annual meeting 2007.4 (2007): 147–48. http://dx.doi.org/10.1299/jsmemecjo.2007.4.0_147.

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Zanellati, Davide, Denis Benasciutti i Roberto Tovo. "Fatigue strength of S355JC steel under harmonic and random bending-torsion loading by a tri-axis shaker: Preliminary experimental results". MATEC Web of Conferences 300 (2019): 17006. http://dx.doi.org/10.1051/matecconf/201930017006.

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A new testing system for applying coupled/uncoupled bending-torsion loading in vibratory tests by a tri-axis shaker has been recently developed at the Department of Engineering of University of Ferrara. The system is composed of a cylindrical specimen with eccentric tip masses, excited by horizontal and/or vertical base accelerations. A special design of the gripping system for specimen constraint allows torsional and bending deformations to be produced and controlled independently, when vertical and horizontal base accelerations are applied simultaneously by the shaker. The values of accelerations and strains in the tested specimens can be monitored continuously. This paper presents a first set of experimental results under harmonic bending and torsion, and under narrow-band combined random loading. Estimations from two frequency-domain approaches are also discussed.

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Alışverişçi, G. Füsun. "The Nonlinear Behavior of Vibrational Conveyers with Single-Mass Crank-and-Rod Exciters". Mathematical Problems in Engineering 2012 (2012): 1–17. http://dx.doi.org/10.1155/2012/534189.

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The single-mass, crank-and-rod exciters vibrational conveyers have a trough supported on elastic stands which are rigidly fastened to the trough and a supporting frame. The trough is oscillated by a common crank drive. This vibration causes the load to move forward and upward. The moving loads jump periodically and move forward with relatively small vibration. The movement is strictly related to vibrational parameters. This is applicable in laboratory conditions in the industry which accommodate a few grams of loads, up to those that accommodate tons of loading capacity. In this study I explore the transitional behavior across resonance, during the starting of a single degree of freedom vibratory system excited by crank-and-rod. A loaded vibratory conveyor is more safe to start than an empty one. Vibrational conveyers with cubic nonlinear spring and ideal vibration exciter have been analyzed analytically for primary and secondary resonance by the Method of Multiple Scales, and numerically. The approximate analytical results obtained in this study have been compared with the numerical results and have been found to be well matched.

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Krake, Luther. "Helicopter Airframe Fatigue Spectra Generation". Advanced Materials Research 891-892 (marzec 2014): 720–25. http://dx.doi.org/10.4028/www.scientific.net/amr.891-892.720.

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Helicopter airframe fatigue cracking is a cause of significant and growing cost of ownership and operational readiness concerns for the operators of (primarily) metallic airframe helicopters. Airframe fatigue has often had relatively low priority for helicopters, with research and design concentrated on the fatigue of flight critical rotating structural components such as rotor blades and pitch links. The Australian Defence Science and Technology Organisation (DSTO) and the US Naval Air Systems Command are collaborating to develop improved methods and technologies that can be used to assess the fatigue damage endured by ageing helicopter airframes. The flight load sequencesor fatigue spectraexperienced by a helicopter airframe in its lifetime contain many billions of load cycles due to rotor revolutions. Fatigue spectra developed for helicopter airframe certification tests are heavily simplified for reasons such as computational efficiency, test practicality and cost. Real airframe fatigue spectra are likely to be influenced by the modes of vibration that might be present on the airframe, the attenuation of the vibratory loading that is introduced at the main and tail rotors and the relative magnitudes and influences of both quasi-static (manoeuvre induced) and vibratory loading. To better capture such complexity, more realistic, higher fidelity fatigue spectra are required. Fatigue spectra generation involves creating realistic flight-by-flight sequences of flight conditions and assigning high-fidelity flight loads data to those sequences. This paper details DSTOs development of a novel computer-automated process which pseudo-randomly generates realistic sequences of flight conditions to match a known or assumed usage spectrum.

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30

Demić, Miroslav, Predrag Popović i Vitomir Pijevac. "A contribution to the determination of actual vibratory loading of a special four axle truck". Vojnotehnicki glasnik 46, nr 6 (1998): 412–20. http://dx.doi.org/10.5937/vojtehg9804412d.

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Mooney, Michael A., i Robert V. Rinehart. "In Situ Soil Response to Vibratory Loading and Its Relationship to Roller-Measured Soil Stiffness". Journal of Geotechnical and Geoenvironmental Engineering 135, nr 8 (sierpień 2009): 1022–31. http://dx.doi.org/10.1061/(asce)gt.1943-5606.0000046.

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Ganapathy, S., i M. A. Parameswaran. "Effect of material loading on the starting and transition over resonance of a vibratory conveyor". Mechanism and Machine Theory 22, nr 2 (styczeń 1987): 169–76. http://dx.doi.org/10.1016/0094-114x(87)90041-3.

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Evgenii, Azarov. "Comparative analysis of experimental research into the effect of lasting self-synchronization on a laboratory shaker with three and two vibration exciters". Izvestiya vysshikh uchebnykh zavedenii. Gornyi zhurnal, nr 3 (20.06.2022): 16–23. http://dx.doi.org/10.21440/0536-1028-2022-3-16-23.

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Introduction. Vibratory transport machines are widely used in the mining industry and other sectors of production. A more detailed analysis of working body oscillation parameters and vibration exciters self-synchronization is required to design vibratory transport machines with new properties. Vibratory machine dynamics was studied with a mathematical model, which made it possible to discover some interesting phenomena, for example, the effect that the authors called the effect of lasting self-synchronization. Research objective is to experimentally confi rm the discovered phenomena using a laboratory shaker and assess the degree of these phenomena resistance. Methods of research. In order to confi rm and carry out the follow-up study of the discovered phenomena, DVM-014 laboratory training facility was designed and manufactured. A set of experiments with two and three vibration exciters were carried out with the help of this facility. Results. The article presents the results of experiments on detecting the effect of lasting self-synchronization under confi gurations with two and three vibration exciters and this phenomenon resistance to the changing position of the machine’s center of mass. Changes in the machine parameters are also given when either one of the two or two of the three vibration exciters are switched off. Summary. Several conclusions have been made based on the experimental results. The most important of them in terms of technology is the following. The phenomenon of lasting selfsynchronization, if any, can be useful when there are pauses in the machine loading. It will signifi cantly reduce energy consumption by switching off one or two motors.

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Leehey, P. "Structural Excitation by a Turbulent Boundary Layer: An Overview". Journal of Vibration and Acoustics 110, nr 2 (1.04.1988): 220–25. http://dx.doi.org/10.1115/1.3269502.

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Thirty years of theoretical and experimental research have yet to resolve a number of questions regarding the vibratory response of, and acoustic radiation from, a structure excited by a turbulent boundary layer (TBL). The most important questions are: (a) Can the TBL be characterized as a Thevenin source—particularly when vibratory power flow into the structure is maximized at hydrodynamic coincidence? Alternatively, at what level does structural vibration fundamentally change the character of the TBL? (b) Is the low wave number portion of the wall pressure spectrum of dominant importance in structural excitation away from hydrodynamic coincidence? Or do structural discontinuities cause the convective ridge of wall pressure to be of greater practical interest? (c) Can one quantify the radiation from a turbulent boundary layer about a rigid finite body? Is it dipole or quadrupole? What is the role of fluctuating wall shear stress? Current research on dense fluid loading and on modeling the behavior of the TBL is yielding new, and sometimes surprising, answers to some of these questions. Free resonant structural vibration in the dense fluid limit and the use of a bounded, non-causal, Green function representing the TBL are two of the surprises discussed.

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Zanellati, Davide, Denis Benasciutti i Roberto Tovo. "An innovative system for uncoupled bending/torsion tests by tri-axis shaker: numerical simulations and experimental results". MATEC Web of Conferences 165 (2018): 16006. http://dx.doi.org/10.1051/matecconf/201816516006.

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This work describes a new testing system for applying a coupled/uncoupled bendingtorsion loading in vibratory tests by a tri-axis shaker. The system is composed of a cylindrical specimen with eccentric tip masses, excited by horizontal and/or vertical base accelerations. The specimen tip is constrained by a lateral thin and flexible plate which impedes any bending when the specimen is excited horizontally, but which permits the specimen torsional rotation. This layout then allows torsional and bending deformations to be produced and controlled independently, when vertical and horizontal base accelerations are applied simultaneously. A finite element model is first used to estimate the system dynamic response and the stresses in the notched specimen section. The model is then validated through experimental tests under harmonic base accelerations. The strains at clamping system are also monitored to indirectly estimate the bending and torsion moment in the specimen. Comparison of numerical and experimental results showed a close correlation and proved that bending-torsion loading are truly uncoupled. Preliminary fatigue tests with harmonic bending loading (vertical base excitation) are finally compared to the constant amplitude S-N curve, showing a quite satisfactory agreement.

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Shakoor, Najia, Kristin J. Lee, Louis F. Fogg, Markus A. Wimmer, Kharma C. Foucher, Rachel A. Mikolaitis i Joel A. Block. "The relationship of vibratory perception to dynamic joint loading, radiographic severity, and pain in knee osteoarthritis". Arthritis & Rheumatism 64, nr 1 (29.12.2011): 181–86. http://dx.doi.org/10.1002/art.30657.

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Oberreiter, Matthias, Michael Horvath, Michael Stoschka i Stefan Fladischer. "Effect of Surface Finishing State on Fatigue Strength of Cast Aluminium and Steel Alloys". Materials 16, nr 13 (30.06.2023): 4755. http://dx.doi.org/10.3390/ma16134755.

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The endurance limit of structural mechanical components is affected by the residual stress state, which depends strongly on the manufacturing process. In general, compressive residual stresses tend to result in an increased fatigue strength. Post-manufacturing processes such as shot peening or vibratory finishing may achieve such a compressive residual stress state. But within complex components, manufacturing-process-based imperfections severely limit the fatigue strength. Thus, the interactions of imperfections, residual stress state and material strength are key aspects in fatigue design. In this work, cast steel and aluminium alloys are investigated, each of them in vibratory finished and polished surface condition. A layer-based fatigue assessment concept is extended towards stable effective mean stress state considering the elastic–plastic material behaviour. Murakami’s concept was applied to incorporate the effect of hardness change and residual stress state. Residual stress relaxation is determined by elastic–plastic simulations invoking a combined hardening model. If the effective stress ratio within the local layer-based fatigue strength is evaluated as critical distance value, a sound calculation of fatigue strength can be achieved. Summing up, the layer-based fatigue strength design is extended and features an enhanced understanding of the effective stabilized mean stress state during cyclic loading.

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Lord, Charles E., i Jem A. Rongong. "A tangential microslip model for circularly and elliptically loaded structures". Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 230, nr 6 (30.09.2015): 900–909. http://dx.doi.org/10.1177/0954406215608409.

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It is well known that the noise and vibration control of structures is a continuing challenge. With many structures this is commonly achieved through passive vibration damping, often using viscoelastic materials. It is sometimes, however, that the use of such materials is not permitted as their properties change over time, or when they are subjected to low and high temperature environments. For these structures and structural elements, it is often that clamping or applied boundary conditions are critical for providing the energy dissipation through microslip. This makes it necessary to understand the level of damping that arises from the clamping zones. In general, the estimation of damping is complicated in that most structures are not unidirectionally loaded and can have a planar path of motion (e.g. gas turbine blades, circular motion valves). Although it is typical during experiments and simulations to reduce a structure into a single axis of excitation, this can often be an over simplification which does not describe the dynamics of the system; but should be included. This paper presents a biaxial planar motion tangential microslip model that accounts for the vibratory loads arising from circular and elliptical motion. This model vectorially decouples and reduces the planar vibratory circular and elliptical motion into two separate independent tangential microslip models. The models account for tip loading and for centroid loading within the microslip region of the clamping zone. Each analytical microslip model is presented and is compared to numerical simulations using finite elements. The analytical models are then coupled to demonstrate the net effect that various eccentricities have on the overall energy dissipation within the structure. The coupled models are then compared to numerical simulations using finite elements through ANSYS.

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Bahrani, Natasha, Juliette Blanc, Pierre Hornych i Fabien Menant. "Alternate Method of Pavement Assessment Using Geophones and Accelerometers for Measuring the Pavement Response". Infrastructures 5, nr 3 (1.03.2020): 25. http://dx.doi.org/10.3390/infrastructures5030025.

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Pavement instrumentation with embeddable in-situ sensors has been a feasible approach to determine pavement deteriorations. Determining pavement deflections during the passage of the load is a promising strategy to determine the overall performance of the pavement. There are different devices that apply loads to the pavements and measure the deflection basin, these include static, vibratory, or impulse loadings. Most commonly used are the static loading like Benkelman beam and impulse loading like the Falling Weight Deflectometer (FWD). However, these techniques are costly and the measurements are recorded infrequently, i.e., once per year or two years. This study focuses on the use of geophones and accelerometers to measure the surface deflections under traffic loading. To develop a method to measure pavement deflections, the sensors were submitted first to laboratory tests, and then tested in situ, in a full scale accelerated pavement test. In the laboratory, the sensors were submitted to different types of loading using a vibrating table. These tests were used to determine the noise and sensitivity of the sensors, and then to evaluate their response to signals simulating pavement deflections under heavy vehicles. The sensor response was compared with measurements of a reference displacement sensor. Different processing techniques were proposed to correct the measurements from geophones and accelerometers, in order to obtain reliable deflection values. Then, the sensors were evaluated in a full scale accelerated test, under real heavy axle loads. Tests were performed at different loads and speeds, and the deflection measurements were compared with a reference anchored deflection sensor. The main advantage of using accelerometers or geophones embedded in the pavement is to enable continuous pavement monitoring, under real traffic. The sensor measurements could also be used to determine the type of vehicles and their corresponding speeds. The study describes in detail the signal analysis needed to measure the pavement deflections accurately. The measurements of pavement deflection can be then used to analyze the pavement behavior in the field, and its evolution with time, and to back-calculate pavement layer properties.

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40

Russo, Anthony, Al Banes, Michelle Elfervig, Mari Tsuzaki, Saturo Yamazaki i Joe Minchew. "4:24 Human annulus cell response to vibratory loading and modulation of the effect by interleukin-1B". Spine Journal 2, nr 5 (wrzesień 2002): 66–67. http://dx.doi.org/10.1016/s1529-9430(02)00310-8.

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Andonov, Anton, Kiril Apostolov, Dimitar Stefanov i Marin Kostov. "Parametric Study on the Floor Response Spectra and the Damage Potential of Aircraft Impact Induced Vibratory Loading". Journal of Disaster Research 5, nr 4 (1.08.2010): 417–25. http://dx.doi.org/10.20965/jdr.2010.p0417.

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Assessment of the effects of a large aircraft impact on a NPP reactor building are the basic topics of the present work. The focus is on the dynamic response of the internal sub-structures, by means of floor response spectra. Factors influencing the floor response spectra, as the nonlinearities of the impact area, load time function shape and the impact velocity are pointed out and subsequent conclusions are made. Alternative motion parameters for assessment of the damage potential and procedure for indirect assessment of the equipment capacity are also discussed.

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42

Sharma, Tanushree, Ankita Gupta, Aseem Sharma, Pulkit Vaid i Kamlesh Singh. "Vibratory stimulation in non-growing patients and its effect on the orthodontic tooth movement". International Journal of Scientific Reports 8, nr 1 (24.12.2021): 33. http://dx.doi.org/10.18203/issn.2454-2156.intjscirep20214935.

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Background: Objectives of the study were to determine the impact of vibratory stimulation in non-growing patients on the orthodontic tooth movement rate and to differentiate the orthodontic tooth movement rate in both experimental and control sides.Methods: 30 non-growing patients were selected for a split-mouth study with fixed appliance therapy orthodontic treatment undergoing bilateral first premolar extractions in maxillary arch. Type 1 active tiebacks were used to perform single canine retraction in all the patients. Vibratory stimulation was provided for 15 minutes daily with the help of Oral-B battery powered toothbrushes of 125 Hz frequency. Measurement was taken with calibrated digital vernier caliper clinically and OPG were taken at regular time intervals using grid method for the tooth movement calculation.Results: P value obtained by statistical calculation shows non-significant results in both experimental and control sides in non-growing patients.Conclusions: Cyclic loading in non-growing patients with fixed orthodontic appliance shows no change in orthodontic tooth movement in experimental and control group.

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Sanders, A. J., K. K. Hassan i D. C. Rabe. "Experimental and Numerical Study of Stall Flutter in a Transonic Low-Aspect Ratio Fan Blisk". Journal of Turbomachinery 126, nr 1 (1.01.2004): 166–74. http://dx.doi.org/10.1115/1.1645532.

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Experiments are performed on a modern design transonic shroudless low-aspect ratio fan blisk that experienced both subsonic/transonic and supersonic stall-side flutter. High-response flush mounted miniature pressure transducers are utilized to measure the unsteady aerodynamic loading distribution in the tip region of the fan for both flutter regimes, with strain gages utilized to measure the vibratory response at incipient and deep flutter operating conditions. Numerical simulations are performed and compared with the benchmark data using an unsteady three-dimensional nonlinear viscous computational fluid dynamic (CFD) analysis, with the effects of tip clearance, vibration amplitude, and the number of time steps-per-cycle investigated. The benchmark data are used to guide the validation of the code and establish best practices that ensure accurate flutter predictions.

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Chidamparam, P., i A. W. Leissa. "Vibrations of Planar Curved Beams, Rings, and Arches". Applied Mechanics Reviews 46, nr 9 (1.09.1993): 467–83. http://dx.doi.org/10.1115/1.3120374.

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This work attempts to organize and summarize the extensive published literature on the vibrations of curved bars, beams, rings and arches of arbitrary shape which lie in a plane. In-plane, out-of-plane and coupled vibrations are considered. Various theories that have been developed to model curved beam vibration problems are examined. An overview is presented of the types of problems which are addressed in the literature. Particular attention is given to the effects of initial static loading, nonlinear vibrations and the application of finite element techniques. The significantly different frequencies arising from curved beam theories which either allow or prevent extension of the centerline during vibratory motion are shown. An extensive bibliography of 407 relevant references is included.

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45

Manwaring, S. R., D. C. Rabe, C. B. Lorence i A. R. Wadia. "Structures and Dynamics Committee Best Paper of 1996 Award: Inlet Distortion Generated Forced Response of a Low-Aspect-Ratio Transonic Fan". Journal of Turbomachinery 119, nr 4 (1.10.1997): 665–76. http://dx.doi.org/10.1115/1.2841176.

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This paper describes a portion of an experimental and computational program (ADLARF), which incorporates, for the first time, measurements of all aspects of the forced response of an airfoil row, i.e., the flow defect, the unsteady pressure loadings, and the vibratory response. The purpose of this portion was to extend the knowledge of the unsteady aerodynamics associated with a low-aspect-ratio transonic fan where the flow defects were generated by inlet distortions. Measurements of screen distortion patterns were obtained with total pressure rakes and casing static pressures. The unsteady pressure loadings on the blade were determined from high response pressure transducers. The resulting blade vibrations were measured with strain gages. The steady flow was analyzed using a three-dimensional Navier–Stokes solver while the unsteady flow was determined with a quasi-three-dimensional linearized Euler solver. Experimental results showed that the distortions had strong vortical, moderate entropic, and weak acoustic parts. The three-dimensional Navier–Stokes analyses showed that the steady flow is predominantly two-dimensional, with radially outward flow existing only in the blade surface boundary layers downstream of shocks and in the aft part of the suction surface. At near resonance conditions, the strain gage data showed blade-to-blade motion variations and thus, linearized unsteady Euler solutions showed poorer agreement with the unsteady loading data than comparisons at off-resonance speeds. Data analysis showed that entropic waves generated unsteady loadings comparable to vortical waves in the blade regions where shocks existed.

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V, Zaselskiy, Popolov D, Zaselskiy I i Shepelenko M. "Experimental research of gantry multirotor vibratory homogenizing mixer continuous vertically-directed action". Theory and practice of metallurgy 1, nr 1 (21.01.2019): 41–48. http://dx.doi.org/10.34185/tpm.1.2019.05.

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The purpose of the work is to determine the laws that reveal the constructive, kinematic and dynamic parameters of the working vibratory homogenizing mixer on the main parameters of the mixing process.To achieve the goal, there were conducted laboratory studies based on planning and implementing a full factor experiment. Results of these studies were analyzed using the math statistics device.As a result, there were received the regression dependences of the gantry multirotor vibratory homogenizing mixer technological parameters in form of polynomials, taking into account the mutual influence of varying structural, kinematic and dynamic parameters. This allowed determining shafts rotation optimal frequency, loading intensity, the inclination angle of the working mixer's body blades. Also, it became possible to establish an optimum dynamic mode, in terms of ensuring the high quality of the mixture with sufficient performance, and the efficient value of vibration acceleration.This is the first time when for a gantry multi-rotor homogenizing mixer of continuous vertically-directed action with blade rotors that parallelly and evenly rotate towards each other, there were received math equations that take into account its constructive, kinematic, and dynamic parameters interactions, and characterize the influence degree of each of the factors on the mixture's quality and mixer's productivity.This allowed to improve the mixture of oiled rolling scale and activated peat preparation technology, before the process of sintering in ArcelorMittal Kryviy Rih agglomeration plant conditions. It also allowed to develop an engineering method for calculating and selecting the main structural and dynamic parameters of the gantry multiportal homogenizing mixer of a continuous, vertically-directed action.

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Neidel, A., M. Giller i S. Riesenbeck. "Metallurgical Failure Analysis of Cracking in Exhaust Stack Liner Fastening Bolts". Practical Metallography 58, nr 10 (1.10.2021): 662–71. http://dx.doi.org/10.1515/pm-2021-0057.

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Abstract Exhaust stack liners of a test rig for gas turbine burners failed locally by ruptured fasteners and fallen-off liner plates. Misalignment of the plating relative to each other and relative to their fasteners caused restraint of the expanding and shrinking liner plates upon start-up and shutdown of the burner rig. The fastening holes of the failed liner plates were not concentric, but misaligned relative to each other and relative to their fastener bolts. This exerted a shear loading on the threads of the fastening bolts, which in turn caused a mean stress shift and damaged the threads of the fasteners by nicking. So pre-loaded, the fastening bolts were not able to withstand the vibratory loads from the flowing exhaust gases and failed due to fatigue.

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Ko, P. L., M. C. Taponat i M. Zbinden. "Wear Studies of Materials for Tubes and Antivibration Bars in Nuclear Steam Generators". Journal of Pressure Vessel Technology 118, nr 3 (1.08.1996): 287–300. http://dx.doi.org/10.1115/1.2842191.

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Wear occurs as a result of relative motion at the interface of two contacting bodies. In nuclear power steam generators, high flow rates can induce vibration of the tubes resulting in wear damage due to impact and sliding contacts between the tubes and their supports. A research project aiming to gain better understanding of the mechanisms and mechanics involved in vibratory wear and to develop a more versatile predictive wear model was carried out. Combinations of Inconel tubes against flat antivibration bars of 403 SS and electrolytic-chrome plated Inconel 600 were tested under conditions of reciprocating sliding and impacting in water at room temperature and at 250°C. The results show that, depending on the material combinations and he loading conditions, distinctively different wear mechanisms and often drastically different wear rates can occur.

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Sherf, Z., A. Katz, P. Hopstone, A. Edelstein, I. Yogev i D. Peleg. "Aspects of the Acoustic Testing of an Electronic System: Acoustic Versus Vibration Testing". Journal of the IEST 47, nr 1 (14.09.2004): 57–66. http://dx.doi.org/10.17764/jiet.47.1.b81113pn56114774.

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In this paper, the vibratory responses excited in an electronic device during a vibration test and an acoustic test are compared. It was found that the responses differ significantly for items mounted on vibration isolators. Under certain circumstances (stiff mounting of the elements in the device and for a certain vibration axis), a higher similarity can be noted between the vibration and acoustic tests. Due to the lack of excitation above 2000 Hz during the vibration testing, failures caused by excitation in this range are not detected, which is significant for small components. The higher responses in the low frequency range during the vibration test can induce unrealistic failures. Application of the vibration test separately for individual axes as opposed to the distributed loading applied during the acoustic test can also result in undetected failures.

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Kotzalas, Michael N., i Tedric A. Harris. "Fatigue Failure Progression in Ball Bearings". Journal of Tribology 123, nr 2 (9.03.2000): 238–42. http://dx.doi.org/10.1115/1.1308013.

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Typically, the life of a component containing rolling contacts is defined as the time to the initiation of a fatigue spall. Initiation of a spall does not always cause the component to stop performing its designed function. Operating the component past the initiation of a spall increases the heat generation rates and vibrations, eventually leading to total failure. A ball/v-ring test rig was used to initiate and progress spalls on bearing balls where spall progression was measured as a function of time, and vibrations monitored using accelerometers. A spall progression life mathematical model for balls endurance tested in the v-ring rig was created by extending the Ioannides–Harris fatigue life theory. Also, excessive vibratory loading was determined to be the major cause of total component failure.

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