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1
Aleksandrov, A. S., T. V. Semenova i N. P. Aleksandrova. "MATERIALS USED IN THE ROAD BASES: METHOD OF THE RESIDUAL DEFORMATIONS’ CALCULATION". Russian Automobile and Highway Industry Journal 16, nr 4 (8.09.2019): 456–71. http://dx.doi.org/10.26518/2071-7296-2019-4-456-471.
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Materials and methods. The authors performed the analysis of the models for calculating residual deformations accumulated by granular materials and under the influence of repeated loads. The research showed the hereditary nature of the strain granular materials’ accumulation. Therefore, the authors used integral calculus for analytical solution of the residual deformation’s dependence on the number of repeated loads and on the magnitude of the main stresses. Moreover, the authors obtained the solution in the form of logarithmic and power functions, which associated the accumulated deformation with the deformation arising from the first load application. In determining the deformation from the first load application, the authors took into account the model of the theory of plasticity, in which the elastoplastic deformation was determined by the sum of two components elastic and plastic, as well as rheological models considering the deformation as the sum of three or four components. Generalizing the model for various materials, the authors gave the preference to the model, in which the elastoplastic deformation was determined by four components: instantaneous elastic and residual deformations, elastic (elastic-viscous) deformation and a viscoplastic component. Therefore, the residual strain from the first load application was represented by the sum of the two components, instantaneous irreversible and viscoplastic. The viscoplastic component of the deformation was a result of stress relaxation in a relatively short period of time equal to the duration of the load impact. Such research allowed taking into account the effect of speed on the duration of the load and the magnitude of the viscoplastic component of the residual deformation. The authors emphasized that taking into account the viscous-plastic component of residual deformation was most appropriate when calculating residual deformations of soils and materials treated with an organic binder. Granular materials were less sensitive to viscoplastic deformation under a single load application, but, when the voltage exceeded the elastic limit, and the more plastic adaptability of crushed stone, gravel, etc. viscoplastic deformation made a significant contribution to the accumulated residual deformation.Results. As a result, the authors carried out the analysis of experimental data on the triaxial compression of various granular materials and determined the parameters obtained for the power and logarithmic functions. The authors studied such materials as granite, gneissic, granodiorite and diorite crushed stone, sand, gravel and crushed stone, gravel mixtures with a mineral part from various rocks and fortified sands.Discussion and conclusions. The paper demonstrates the possibility of using the solutions for calculation of the surface displacement of the pavement layers of granular materials. The authors formulate the tasks for further research.
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Da, Kang, Wang Yongliang, Zhong Jingjun i Liu Zihao. "Pre-Deformation Method for Manufactured Compressor Blade Based on Load Incremental Approach". International Journal of Turbo & Jet-Engines 37, nr 3 (27.08.2020): 259–65. http://dx.doi.org/10.1515/tjj-2017-0024.
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AbstractThe blade deformation caused by aerodynamic and centrifugal loads during operating makes blade configurations different from their stationary shape. Based on the load incremental approach, a novel pre-deformation method for cold blade shape is provided in order to compensate blade deformation under running. Effect of nonlinear blade stiffness is considered by updating stiffness matrix in response to the variation of blade configuration when calculating deformations. The pre-deformation procedure is iterated till a converged cold blade shape is obtained. The proposed pre-deformation method is applied to a transonic compressor rotor. Effect of load conditions on blade pre-deformation is also analyzed. The results show that the pre-deformation method is easy to implement with fast convergence speed. Neither the aerodynamic load nor centrifugal load can be neglected in blade pre-deformation.
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Anderson, William D., Sydney L. M. Wilson i David W. Holdsworth. "Development of a Wireless Telemetry Sensor Device to Measure Load and Deformation in Orthopaedic Applications". Sensors 20, nr 23 (27.11.2020): 6772. http://dx.doi.org/10.3390/s20236772.
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Due to sensor size and supporting circuitry, in-vivo load and deformation measurements are currently restricted to applications within larger orthopaedic implants. The objective of this study is to repurpose a commercially available low-power, miniature, wireless, telemetric, tire-pressure sensor (FXTH87) to measure load and deformation for future use in orthopaedic and biomedical applications. The capacitive transducer membrane was modified, and compressive deformation was applied to the transducer to determine the sensor signal value and the internal resistive force. The sensor package was embedded within a deformable enclosure to illustrate potential applications of the sensor for monitoring load. To reach the maximum output signal value, sensors required compressive deformation of 350 ± 24 µm. The output signal value of the sensor was an effective predictor of the applied load on a calibrated plastic strain member, over a range of 35 N. The FXTH87 sensor can effectively sense and transmit load-induced deformations. The sensor does not have a limit on loads it can measure, as long as deformation resulting from the applied load does not exceed 350 µm. The proposed device presents a sensitive and precise means to monitor deformation and load within small-scale, deformable enclosures.
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Williamson, M., i A. Majumdar. "Effect of Surface Deformations on Contact Conductance". Journal of Heat Transfer 114, nr 4 (1.11.1992): 802–10. http://dx.doi.org/10.1115/1.2911886.
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This study experimentally investigates the influence of surface deformations on contact conductance when two dissimilar metals are brought into contact. Most relations between the contact conductance and the load use the surface hardness to characterize surface deformations. This inherently assumes that deformations are predominantly plastic. To check the validity of this assumption, five tests were conducted in the contact pressure range of 30 kPa to 4 MPa, with sample combinations of (I) smooth aluminum-rough stainless steel, (II) rough aluminum-smooth stainless steel, (III) rough copper-smooth stainless steel, (IV) smooth copper-rough stainless steel, and (V) smooth aluminum-smooth stainless steel. The experimental results of tests I, II, and IV indicate that the conductance of the first load-unload cycle showed hysteresis, suggesting that the plastic deformation was significant. However, for subsequent load cycles, no conductance hysteresis was observed, implying that elastic deformation was predominant. In contrast, no conductance hysteresis was observed for all load-unload cycles of tests III and V. Therefore, the surface deformation for this combination was always predominantly elastic. In practical applications where plastic deformation is significant for the first loading, mechanical vibrations can produce oscillating loads, which can finally lead to predominance of elastic deformation. Comparison of the results of tests II and V show that even though plastic deformation was significant for the first loading of a rough aluminum surface, elastic deformation was always predominant for the smoother aluminum surface
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Barchukova, Tetіana. "Work piles - columns with soil under constant influence of vertical and cyclically approximated horizontal loads". ACADEMIC JOURNAL Series: Industrial Machine Building, Civil Engineering 2, nr 51 (12.10.2018): 19–23. http://dx.doi.org/10.26906/znp.2018.51.1283.
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The article describes an experimental study aimed at identifying common patterns of joint work of piles - columns with soil with vertical and cyclically applied horizontal loads. The study examines the deformation processes occurring in the soil. At any pressure value, soil deformations can be divided into two groups, which are restored (elastic) and residual. When the pressure is less than the structural strength, elastic deformations appear. With a pressure of greater structural strength, elastic and residual deformations appear. Elastic deformations appear throughout the depth, residual deformations develop in the depth of the deformation zone, where the stress exceeds the structural strength of the soil. After removing the load, the elastic deformation disappears, and the residual remains. The lower limit of the residual strain zone is at a depth, where the stresses from the load transmitted by the column of piles below its base are balanced by the structural strength of the soil.
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CELMS, A., I. TREVOHO, V. CELMINA i M. BRINKMANIS-BRIMANIS. "Technologies of building deformation monitoring in Latvia". Modern achievements of geodesic science and industry 2, nr 44 (1.09.2022): 53–59. http://dx.doi.org/10.33841/1819-1339-2-44-53-59.
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Determining the deformations of a building is a very important process in the construction and operation of a construction site. The main causes of deformation of structures and their foundations are sedimentation of foundation structures, weak load-bearing soil, crushed sand layers, wear and degradation of building foundations, uneven or excessive loading of foundations, poor condition of pile foundations, regular ambient vibrations, support of ambient temperature, various loads caused by wind, snow and other conditions, uncompact soil. The quality of building materials, binders, and aggregates can also be mentioned as the causes of the deformations of buildings and foundations. The paper analyzes the available information and regulatory enactments related to the monitoring of building deformations, evaluates the provision of building deformation in Latvia, describes the types of building deformations and their causes, building deformation monitoring technologies, as well as building monitoring methods, and summarizes the results. The aim of the study is to investigate and evaluate the deformation monitoring system of buildings. The results of the research reflect the procedures and technologies of deformation monitoring of buildings, the possibilities of using high-precision deformation sensors, substantiating the need to create an automated height, load, and other deformation-causing properties, and measurement control system. The work provides a specific assessment of the building deformation monitoring object in Strēlnieku Street in Riga.
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Tateyama, Kohei, i Hiroyuki Yamada. "Nonuniform Deformation of Cell Structures Owing to Plastic Stress Wave Propagation". Applied Mechanics 2, nr 4 (5.11.2021): 911–31. http://dx.doi.org/10.3390/applmech2040053.
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In cell structures, unlike in dense bodies, nonuniform deformation occurs from the impact end, even at velocities in the order of tens to hundreds of meters per second. In this study, we experimentally examine the nonuniform deformation mechanism of cell structures. They prepared two kinds of specimens: nickel foam (Ni foam) and silicone-rubber-filled nickel foam (Ni/silicone foam). As a dynamic and impact test method (compression velocity of 20 m/s or more), we used a dynamic and impact load-measuring apparatus with opposite load cells to evaluate the loads on both ends of the specimen in one test. At compression velocities of 20 m/s or less, no nonuniform deformations were observed in the Ni foam and the Ni/silicone foam, and the loads on the impact and the fixed ends achieved force equilibrium. The Ni foam showed no change with an increasing strain rate, and the Ni/silicone foam showed a strong strain rate dependence of the flow stress. At a compression velocity of approximately 26 m/s, the loads differed at the two ends of the Ni/silicone foam, and we observed nonuniform deformation from the impact end. The results of the visualization of the load and deformation behavior obtained from both ends of the specimen revealed that the velocity of the plastic stress wave and the length of the specimens are important for nonuniform deformation.
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Aleksandrov, A. S., T. V. Semenova i N. P. Aleksandrova. "Calculation of Residual Deformations of Granulated Materials from Exposure to Repeated Loads". Materials Science Forum 992 (maj 2020): 828–35. http://dx.doi.org/10.4028/www.scientific.net/msf.992.828.
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The analysis of the models for calculating residual deformations accumulated by granular materials under the influence of repeated loads is performed. Determined the hereditary nature of the accumulation of deformation of granular materials. This allowed the use of integral calculus for the analytical solution of the problem of the dependence of residual deformation on the number of repeated loads, the value of the main stresses. The solution is obtained in the form of logarithmic and power-law functions that associate the accumulated deformation with the deformation arising from the first load application with the number of applied loads. The deformation from the first load application is represented by the sum of the two components, instantaneous irreversible and viscoplastic. The viscoplastic component of the deformation is a consequence of stress relaxation in a relatively short period of time equal to the duration of the impact of the load. The analysis of experimental data on the triaxial compression of various granular materials is carried out and the parameters obtained for the power and logarithmic functions are determined. The materials studied include: granite, gneissic, granodiorite and diorite crushed stone, sand and gravel and crushed stone and gravel mixtures with a mineral part from various rocks, fortified sands. The possibility of application of the obtained solutions for the calculation displacement of the surface of the pavement layers of granular materials is shown. The tasks of further research are formulated.
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Todic, M., V. Golubović-Bugarski, M. Merdanić i T. Latinović. "Deformation state of the load-bearing structure of a four-column the press". Journal of Physics: Conference Series 2540, nr 1 (1.07.2023): 012030. http://dx.doi.org/10.1088/1742-6596/2540/1/012030.
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Abstract During the operation of each machine, the deformation and stress state of its supporting structure is directly related to the load. The load intensity ranges from the minimum to the maximum value and is a function of nominal force, torque, and kinematic-dynamic values of moving and executive assemblies during the machine operation process. The intensity of deformations is also a function of the shape and type of the supporting structure. However, although the supporting structure is reliable, which refers to its integrity, the production of a quality workpiece (product) does not have to be reliable. Therefore, it is important that the deformation states of the supporting structure be in the appropriate tolerance field, regardless of the intensity of the load. If the intensity of deformations is outside a certain field, it will directly affect the quality of the workpiece that is made on the subject machine. It is known that load-bearing structures can be of open and closed types, load-bearing structures of closed type are used for higher loads and larger workpiece dimensions. By installing sensors on the elements of the supporting structure with accompanying measuring chains in real-time, the deformation state of certain elements or places on the supporting structure can be monitored, based on which the reliable quality of the workpiece can be influenced.
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Kondrashin, K. G., R. A. Petrov i N. A. Raktovich. "Accumulation of irreversible deformation of soils as a result of repeated loading". Herald of Dagestan State Technical University. Technical Sciences 49, nr 2 (17.08.2022): 143–49. http://dx.doi.org/10.21822/2073-6185-2022-49-2-143-149.
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Objective. The purpose of the study is to establish the patterns of accumulation of irreversible soil deformations from repeated loading.Method. When loading soils, the balance between external and internal forces is established gradually over a more or less long time. Therefore, with a single application of a cyclic load, such an equilibrium can be achieved only in a relatively long time.Result. An approximate method is proposed for calculating the magnitude of the deformation developed as a result of the action of a cyclic load. The cases are determined when it is necessary to take into account the viscous component of deformation and when the latter can be neglected. It has been established that when determining the deformation of soils that has developed during a single application of such cyclic loads that are characteristic of the process of their compaction by machines, in all cases, except for rolling them with rollers on pneumatic tires, the viscous component of deformation can be ignored.Conclusion. In a relatively short time of the load, the state of equilibrium can be achieved only in the process of soil deformation by repeated loading. With an increase in the number of loading repetitions, the soil gradually hardens, and the deformation decreases. This occurs both due to the irreversible and reversible parts of the deformation. Consequently, the soil deformation modulus increases from cycle to cycle.
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Ruan, Jiang Tao, Shi Bin Wang, Jing Wei Tong, Min Shen, Francesco Aymerich i Pierluigi Priolo. "Deformation in Impacted Stitched Composite Plates Subjected to Compressive Load". Advanced Materials Research 393-395 (listopad 2011): 36–39. http://dx.doi.org/10.4028/www.scientific.net/amr.393-395.36.
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The study on deformation in impact-damaged graphite-fibre/epoxy stitched composite plates subjected to compressive load is presented. A delaminated cross-ply laminate [03/903]S obtained in low-velocity impact test has been examined using a self-designed anti-buckling device in compressive experiment. The out-of-plane displacement field of the specimen has been measured with an optical whole-filed measurement technique, which is carrier electronic speckle pattern interferometry (carrier-ESPI). Finite element (FE) simulation is also carried out to predict the deformation. The effect of the stitching line on compressive deformation is discussed for various stitched laminates. Finally, the numerical results are compared with experimental measurement deformations under different compressive loads.
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SELYAEV, Vladimir P., Nikolay N. KISELEV i Oleg V. LIYASKIN. "DIAGRAMS OF VACUUM INSULATING PANEL DEFORMATION DURING COMPRESSION". Urban construction and architecture 9, nr 3 (15.09.2019): 17–21. http://dx.doi.org/10.17673/vestnik.2019.03.3.
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The possibility of using vacuum insulation panels (VIP) with a granular filler for the manufacture of threelayer enclosing wall panels, floor slabs and coatings is considered. The results of experimental studies of vacuum insulation panels, carried out with the aim of analytically describing the deformation diagrams of VIP panels under the action of a compressive load, are presented. It has been established: deformative properties of vacuum insulation panels with granular filler do not depend on the size of the filler particles, but depend on the volume content of the filler; a deformation diagram describing the relationship between stresses and relative deformations during compression of a vacuum insulating panel with a granular filler can be approximated by the function G. B. Bülfinger. The results obtained make it possible by calculation to determine the stress state in flat plating sheets during local load transfer.
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Hao, Liangjun, Weili Gong, Manchao He, Yanqi Song i Jiong Wang. "Dynamic Model and Mechanical Properties of the Two Parallel-Connected CRLD Bolts Verified with the Impact Tensile Test". Mathematical Problems in Engineering 2018 (4.10.2018): 1–17. http://dx.doi.org/10.1155/2018/1423613.
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Dynamic model was theoretically established for the two parallel-connected constant-resistance-large-deformation (CRLD) bolts, and the theoretical results were experimentally verified with impact tensile tests on the CRLD bolts samples. The dynamic responses of the double CRLD bolts were investigated under the impact loads with different intensities. The theoretical analyses showed that (1) under relatively small loading the CRLD bolts deform elastically and the deformation finally returns to zero and (2) under the high impact load, including the stable impact load and unstable impact load, the CRLD bolts export structural deformation after the initial elastic deformation. The deformation of the bolts eventually stabilizes at a certain amount of the elongation caused by the relative sliding of the sleeves and rebars. The essential difference between the stable impact load and unstable impact load is that, under the stable impact load, no structural deformation will occur after the impact load ends; under the unstable impact load, the structural deformation will still occur after the impact load ends. The obtained results are of theoretical implications for rock support design with CRLD bolts under the dynamical loading condition.
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Kim, Min-Geun, Bonyong Koo, You-Sung Han i Minho Yoon. "Asymmetric Design Sensitivity and Isogeometric Shape Optimization Subject to Deformation-Dependent Loads". Symmetry 13, nr 12 (9.12.2021): 2373. http://dx.doi.org/10.3390/sym13122373.
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We present a design sensitivity analysis and isogeometric shape optimization with path-dependent loads belonging to non-conservative loads under the assumption of elastic bodies. Path-dependent loads are sometimes expressed as the follower forces, and these loads have characteristics that depend not only on the design area of the structure but also on the deformation. When such a deformation-dependent load is considered, an asymmetric load stiffness matrix (tangential operator) in the response region appears. In this paper, the load stiffness matrix is derived by linearizing the non-linear non-conservative load, and the geometrical non-linear structure is optimally designed in the total Lagrangian formulation using the isogeometric framework. In particular, since the deformation-dependent load changes according to the change and displacement of the design area, the isogeometric analysis has a significant influence on the accuracy of the sensitivity analysis and optimization results. Through several numerical examples, the applicability and superiority of the isogeometric analysis method were verified in optimizing the shape of the problem subject to deformation-dependent loads.
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Sayed, Ahmed M. "Numerical Analysis of Single-Angle Steel Member Under Tension Force with Different End Deformations". Civil Engineering Journal 6, nr 8 (1.08.2020): 1520–33. http://dx.doi.org/10.28991/cej-2020-03091564.
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Steel members with a single-angle cross-section are widely used, but some of their behaviours under loads are not considered by design codes, necessitating related research. This study is carried out on fifty steel single-angle members focused on the stress distribution behaviour and the ultimate axial load capacities under different end deformations through 3-dimensional Finite Element (FE) simulations and comparison with previous experimental findings. FE modeling is capable of modeling steel structures with high accuracy. Based on the results, the length of the angle affects neither the shape of the stress distribution nor the ultimate load capacity of the element. The end deformations affect the stress distribution on the member angle cross-section, including the ultimate load capacity. The end deformations which restricted deformations in the two directions perpendicular to the load axis are found to be optimal, with an average increase in load capacity by a factor of 1.96 for an equal angle and 2.21 for an unequal angle compared with the capacities calculated for single angles with deformations allowed in all directions. The appearance of a compression zone on the unconnected angle leg reduces the ultimate load capacity. The current design code (ANSI/AISC-360) can be adopted to calculate the ultimate load in the case of no deformation in the y-axis direction and no deformations in the x- and y-axis directions where the mean ratios of PNum/Pcode are 1.24 and 1.34 respectively. However, the code does not agree with the end deformations of free deformations and no deformation in the x-axis direction for either equal or unequal angles where the mean ratios of PNum/Pcode are 0.64 and 0.79 respectively, which is unsafe.
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Yang, J., i K. Komvopoulos. "A Mechanics Approach to Static Friction of Elastic–Plastic Fractal Surfaces". Journal of Tribology 127, nr 2 (1.04.2005): 315–24. http://dx.doi.org/10.1115/1.1828080.
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A contact mechanics theory of static friction is presented for isotropic rough surfaces exhibiting fractal behavior. The analysis is based on a piecewise power-law size distribution and a normal slope distribution of the asperity contacts and elastic–fully plastic deformation models. Numerical integration yields solutions for the normal and friction forces in terms of fractal parameters, elastic–plastic material properties, and interfacial shear strength. The variation of the static coefficient of friction with normal load is related to the effect of the surface topography on the dominant deformation mode at the asperity contacts. Plastic deformation of the smaller asperity contacts dominates at low loads and elastic deformation of the larger asperity contacts dominates at high loads. The critical load signifying the transition from predominantly plastic to elastic deformation depends on the fractal parameters and material properties. In the low-load range, the static coefficient of friction decreases with the increase of the load, while in the high-load range it increases with the load. Numerical results for copper fractal surfaces illustrate the effects of normal load, surface topography, and interfacial shear strength on the static coefficient of friction.
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Ma, X. G., i K. Komvopoulos. "Pseudoelasticity and Shape Memory Effects on Deformation Recovery of Indented Titanium-Nickel Alloy Films". Nanoscience and Nanotechnology Letters 11, nr 9 (1.09.2019): 1313–17. http://dx.doi.org/10.1166/nnl.2019.3000.
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The deformation behavior of shape-memory titanium-nickel (TiNi) alloy films indented by diamond tips of various nominal radius of curvature under different contact loads was investigated by nanoindentation. Pseudoelasticity and shape-memory effect (SME) strongly affected the deformation recovery of the indented films. The effects of tip radius and maximum indentation load on the deformation recovery of austenitic and martensitic TiNi films are interpreted in terms of associated deformation mechanisms controlled by pseudoelasticity, SME, and dislocations. The results reveal the important roles of pseudoelasticity and SME on the capacity of TiNi films to either fully annihilate or partially recover from deformation induced by nanoindentation, illustrating a high potential for applications requiring large reversible deformations.
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MOHAMMED, ASHIRU, Yusuf Dada Amartey, ABDULFATAI ADINOYI Murana i Adamu Lawan. "EVALUATING THE INFLUENCE OF TRAIN AXLE LOAD ON RAILWAY BALLAST DEGRADATION AND AXIAL DEFORMATION". FUDMA JOURNAL OF SCIENCES 6, nr 1 (1.04.2022): 210–15. http://dx.doi.org/10.33003/fjs-2022-0601-871.
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Degradation and axial deformations of railway ballast bed are highly influenced by stresses induced by moving trains. Hence, this study evaluate the influence of train axle load on the rate of degradation and axial deformation of railway ballast bed. Series of cyclic loading test were conducted at intervals of 200,000 load cycles up to 1,000,000 cycles. Two trains with capacities of 30 ton and 24 tons for freight and passengers respectively were simulated at a typical moving speed of 120 km/hr which is equivalent to a frequency of 16.5 Hz. It was observed that with an increase in both axle load and number of load cycles, the degradation index and the axial deformation increased. It was also observed that ballast degradation has a strong influence on the ballast bed deformation. Hence, ballast degradation is highly influenced by train axle load and the axial deformation of the ballast bed has a strong correlation with the rate of ballast particles degradations
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Mishra, Debakanta, Huseyin Boler, Erol Tutumluer, Wenting Hou i James P. Hyslip. "Deformation and Dynamic Load Amplification Trends at Railroad Bridge Approaches". Transportation Research Record: Journal of the Transportation Research Board 2607, nr 1 (styczeń 2017): 43–53. http://dx.doi.org/10.3141/2607-07.
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Railroad track transitions such as bridge approaches may experience differential movements due to variations in track stiffness; impact loads due to train speed and excessive vibration; ballast settlement from fouling, degradation, or both; tie–ballast contact condition and gap; and settlement of fill, subgrade, and foundation layers. A research study completed recently at the University of Illinois focused on identifying the major causes of this differential movement and implementing suitable rehabilitation measures to mitigate recurrent problems with settlement and geometry. Transient and permanent deformation trends were observed in track substructure layers at two instrumented bridge approaches along the Amtrak Northeast Corridor. Multidepth deflectometer systems installed through crossties successfully recorded both permanent (plastic) and transient deformations of individual track substructure layers. Strain gauges mounted on the rail effectively measured vertical wheel loads applied during train passage and monitored the support conditions under the instrumented crossties. Track settlement (or permanent deformation) data revealed that the ballast layer was the primary source of differential movement contributing to recurrent settlement and geometry problems. Transient layer deformations recorded under train passage were higher in the ballast than in any other substructure layer. Transient displacement and wheel load data were consistently higher at near-bridge locations than at open-track locations. Rail-mounted strain gauges indicated that load amplification levels were significantly higher at near-bridge locations than at open-track locations.
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Hasap, Anat, Phanasindh Paitekul, Nitikorn Noraphaiphipaksa i Chaosuan Kanchanomai. "Influence of toe load on the fatigue resistance of elastic rail clips". Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 232, nr 4 (24.05.2017): 1078–87. http://dx.doi.org/10.1177/0954409717707834.
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As a critical component of the fastening system, the elastic rail clip maintains the rail in the vertical, lateral, and longitudinal positions using its specified toe load. In this study, the influence of toe load on the deformation and fatigue resistance of the clip was studied. Finite element analysis, static load experiments, and fatigue experiments were performed to evaluate the deformation and fatigue resistance of the clip. With the contribution of the lateral wheel load, the deformation range of the outer clip was higher than that of the inner clip. Therefore, the cyclic deformation of the outer clip was used for the fatigue experiment. The toe load had no influence on the fatigue resistance of the clip under normal wheel load, i.e. the clips under high, normal, and low toe loads were run-out at 5 × 106 cycles. However, with the contribution of impact on the wheel load, the fatigue lives were reduced to 5468 cycles and 16,839 cycles for the clips under high and normal toe loads, respectively. In the case of low toe load, the clip under the contribution of impact could withstand more than 5 × 106 cycles. Accordingly, the reduction of toe load may enhance the fatigue resistance of the clip under impact.
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Kelly, J. M. "Shear Deformation and Buckling of Columns". Applied Mechanics Reviews 44, nr 11S (1.11.1991): S160—S165. http://dx.doi.org/10.1115/1.3121348.
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It is shown that the prediction of buckling loads of columns that are very weak in shear is crucially dependent on the choice of direction for the axial load of the column in the buckled configuration. Examples are given showing the wide differences in buckling load predicted by different choices. The results are applicable to columns of sandwich construction, springs, and multilayer elastomeric bearings for isolation systems.
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Wu, Y. Q., Han Huang i Jin Zou. "Deformation of Monocrystalline Silicon under Nanoscratching". Advanced Materials Research 41-42 (kwiecień 2008): 15–19. http://dx.doi.org/10.4028/www.scientific.net/amr.41-42.15.
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In this work, deformation of monocrystalline silicon (Si) under nanoscratching was investigated using transmission electron microscopy (TEM). The results indicated that no fracture occurred during nanoscratching with loads ranging from 1 to 6 mN. The damaged regions induced by nanoscratching included an amorphous Si region and a damaged crystalline Si region. Detailed TEM analyses revealed that at the lowest load of 1 mN no dislocation was observed in the damaged crystalline region, and only stacking faults were observed at the boundary between the damaged crystalline Si and amorphous Si. Dislocations started to nucleate along (111) planes and penetrated into the bulk Si when the normal load was increased to 2 mN and above. Defects perpendicular to the scratched surface were initiated when the load was greater than 4 mN. The density of dislocations also increased rapidly with the increase of the applied load.
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Mill, Tarvo, Artu Ellmann, Martti Kiisa, Juhan Idnurm, Siim Idnurm, Milan Horemuz i Andrus Aavik. "Geodetic monitoring of bridge deformations occurring during static load testing". BALTIC JOURNAL OF ROAD AND BRIDGE ENGINEERING 10, nr 1 (10.03.2015): 17–27. http://dx.doi.org/10.3846/bjrbe.2015.03.
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Terrestrial laser scanning technology has developed rapidly in recent years and has been used in various applications but mainly in the surveying of different buildings and historical monuments. The use for terrestrial laser scanning data for deformation monitoring has earlier been tested although conventional surveying technologies are still more preferred. Since terrestrial laser scanners are capable of acquiring a large amount of highly detailed geometrical data from a surface it is of interest to study the metrological advantages of the terrestrial laser scanning technology for deformation monitoring of structures. The main intention of this study is to test the applicability of terrestrial laser scanning technology for determining range and spatial distribution of deformations during bridge load tests. The study presents results of deformation monitoring proceeded during a unique bridge load test. A special monitoring methodology was developed and applied at a static load test of a reinforced concrete cantilever bridge built in 1953. Static loads with the max force of up to 1961 kN (200 t) were applied onto an area of 12 m² in the central part of one of the main beams; the collapse of the bridge was expected due to such an extreme load. Although the study identified occurrence of many cracks in the main beams and significant vertical deformations, both deflection (–4.2 cm) and rising (+2.5 cm), the bridge did not collapse. The terrestrial laser scanning monitoring results were verified by high-precision levelling. The study results confirmed that the TLS accuracy can reach ±2.8 mm at 95% confidence level.
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Cederbaum, G., i R. A. Heller. "Dynamic Deformation of Orthotropic Cylinders". Journal of Pressure Vessel Technology 111, nr 2 (1.05.1989): 97–101. http://dx.doi.org/10.1115/1.3265664.
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The theory of thick orthotropic shells is used here to analyze a cylinder subjected to dynamic loads. The formulation includes shear deformation and rotatory inertia effects similarly to the first-order, shear deformation, laminated plate theory. Dynamic line loads (along the longitudinal direction) and patch loads are considered. The time-dependent part of the load is a step pulse or a half-sine wave.
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Sahoo, Vineet, i Rathindranath Maiti. "Static load sharing by tooth pairs in contact in internal involute spur gearing with thin rimmed pinion". Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 230, nr 4 (marzec 2016): 485–99. http://dx.doi.org/10.1177/0954406215618424.
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Involute toothed internal−external standard gear sets are modeled for load-sharing by the teeth pairs in mesh along the line of contact. An analytical solution is proposed. Considering the rigid body in rotation, it is assumed that angular rotation of a gear with respect to the other gear due to deformation along the line of contact is equal. The sum of the normal loads in all tooth pairs in contacts, which equals to the total transmitted load, is considered constant. All possible deformations such as, tooth bending deflection, tooth compressive (contact) deformation, tooth foundation deflection and tooth shearing deflection are considered in analyses. Detailed tooth geometries are incorporated in modeling. Ultimately, the map of load sharing by tooth pairs in contacts, at different angular position, over a cycle of similar contact pattern, is established. Finally, considering thin rimmed gears, the effects of the rim thickness on load sharing, which is the aim of the present investigation are analyzed and the results are presented in terms of backup ratios.
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Tani, J. "Buckling of Truncated Conical Shells Under Combined Axial Load, Pressure, and Heating". Journal of Applied Mechanics 52, nr 2 (1.06.1985): 402–8. http://dx.doi.org/10.1115/1.3169061.
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On the basis of the Donnell-type shell equations with the effect of nonlinear prebuckling deformations taken into consideration, a theoretical analysis is performed on the buckling of clamped truncated conical shells under two loads combined out of uniform pressure, axial load, and uniform heating. The problem is solved by a finite difference method. It is found that the interaction curves of buckling loads are changed remarkably by the difference in the shape of conical shells. This is due to the large nonlinear prebuckling deformation and the difference in the buckling mode between two cases of single load.
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Li, Xiaofeng, i Zhixiang Yin. "Study of Creep Mechanical Properties and a Rheological Model of Sandstone under Disturbance Loads". Processes 9, nr 8 (26.07.2021): 1291. http://dx.doi.org/10.3390/pr9081291.
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The stress environments of rock masses are complex. To explore the mechanical properties of sandstone under earthquake or disturbance loads, laboratory triaxial creep tests under different disturbance loads were conducted on sandstone from Fuxin, Liaoning Province, China. Given the disturbance load, a creep deformation pattern for sandstone was analyzed, and the influence of the disturbance load on the mechanical properties of rock was considered. Thus, a constitutive model of rock under creep disturbance load was established. The results show that (1) the creep curve can be divided into four stages: attenuation creep, steady creep, disturbance creep, and acceleration creep; the increment of disturbance creep varies for different disturbance loads and the larger the disturbance load, the larger the disturbance creep deformation; (2) with increasing disturbance loads, the long-term strength, failure time, and elastic modulus of sandstone decreases linearly, while the peak strain increases; and (3) considering the influence of the disturbance load and introducing an acceleration element to modify the Nishihara model, a constitutive model describing the whole deformation process of sandstone under creep disturbance load was established. The accuracy of the model was verified by test data and provides a theoretical basis for rock mass stability analysis.
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Qu, Wei Qiang, i Xu Chen. "Ratcheting Behavior of Pressurized Elbow Pipe under Different Loading Modes". Applied Mechanics and Materials 853 (wrzesień 2016): 322–27. http://dx.doi.org/10.4028/www.scientific.net/amm.853.322.
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Ratcheting deformation is studied on elbow pipe made of Z2CND18.12N by FEM software. The simulation is conducted by ANSYS. Chen-Jiao-Kim (CJK) kinematic hardening model is added in ANSYS for the study. The elbow pipe is subjected to internal pressure and reversed in-plane bending. Internal pressure can be constant or cyclic. Many different loading paths are used in the study. Ratcheting deformations of under different ways are studied. The result shows that ratcheting deformation occurs mainly in the circumferential direction. Ratcheting deformation at the crown and intrados of elbow pipe is more notable because of higher stress. Tensile or compressed load can influence the position of dangerous point. It is found that ratcheting deformations under different paths with same peak load are different.
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Wu, Ji, Shu Lin Duan, Zhan Hua Wu, Hui Xing i Qin An Liu. "The Coupled Thermal and Mechanical Load Analysis in the 6S50MC-C Type Marine Diesel' Piston". Advanced Materials Research 690-693 (maj 2013): 1909–13. http://dx.doi.org/10.4028/www.scientific.net/amr.690-693.1909.
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MAN Diesel’s 6S50MC-C two-stroke marine diesel engine is researched in this paper. The intensity under the effect of thermal load, mechanical load and coupled loads are analyzed. As the boundary conditions of the temperature field distribution, the mean temperature and the mean heat transfer coefficient are calculated firstly. Based on the temperature field, the thermal intensity is obtained in ANSYS. Then the study analyzes the stress and the strain distribution when the mechanical load and the coupled loads are applied. Through the analysis of different loads, the maximum stress is 696MPa in thermal load, 191MPa in mechanical load and 659MPa in coupled loads. The maximum deformation is 1.011mm in thermal load, 0.147mm in mechanical and 1.022mm in coupled loads. The intensity meets the design requirement. The stress concentration and the deformation of the piston crown mainly are generated by the thermal load. To reduce the destructive effect of thermal, it requests enhancing cooling and warming up the main engine.
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Pertseva, Olga N., Gleb V. Martynov, Daria E. Monastyreva, Ekaterina I. Pereladova, Zaur S. Daurov i Roman S. Tikhonov. "The sustainability of micropolar concrete plasticity model to the finite element size". Vestnik MGSU, nr 5 (maj 2019): 559–69. http://dx.doi.org/10.22227/1997-0935.2019.5.559-569.
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Introduction. As it is known, deformation of concrete can be divided into several stages. The first stage is characterized by a linear dependence of deformations and stresses, elastic deformations and small loads that, as they increase, lead to the second stage. At the second stage, the dependence becomes curvilinear, while deformations are irreversible, since micro-cracks are formed. Further consolidation of the micro-cracks into meso- and main cracks refers to the third stage and is accompanied by a redistribution of energy to the area of the main crack mouth. However, reaching the ultimate strength is not accompanied by an instant loss of bearing capacity due to the effect of decompression. This phenomenon should be taken into account in the numerical simulation of concrete and reinforced concrete structures, because it significantly affects their strength characteristics. The introduction of such a refinement in the design models will allow reducing cross-sections of the construction components and accordingly getting rid of material overruns.
Materials and methods. A digital sample is created for the study using the ANSYS software. A beam model is simulated as a single-span beam with longitudinal reinforcement in the bending zone. The load is applied as a 70 mm offset to the nodes in the line along the application point. Reinforcement is simulated as bilinear isotropic strengthening elements (LINK180). For uniform load distribution, load plates with linear elastic properties are specified at the points where boundary conditions and load are applied.
Results. According to the obtained data, stress-deformation curves are constructed identically to the concrete deformation diagram. The values of loads when the first cracking occurs (end of the linear-elastic state), peak loads when the main crack is formed (maximum load for the unreinforced case and the beginning of the steel softening for the reinforced case) as well as ultimate loads and maximum deflections at the mid-span are compared.
Conclusions. The results give insignificant (up to 5 %) discrepancies when changing the finite element size. Therefore, when working with calculation software, developers will be able to create correct models with any spacing of the finite element mesh depending on the available computational capabilities. Micropolar theory for simulating the concrete decompression can be considered sustainable to the size of the finite elements.
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Pyles, Marvin R., i Joan Stoupa. "Load-Carrying Capacity of Second-Growth Douglas-Fir Stump Anchors". Western Journal of Applied Forestry 2, nr 3 (1.07.1987): 77–80. http://dx.doi.org/10.1093/wjaf/2.3.77.
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Abstract In order to quantify the stump anchor capacity of small second-growth Douglas-fir (Pseudotsuga menziesii [Mirb]. Franco) trees, load tests to failure were conducted on 18 stumps from trees 7 to 16.5 in dbh. The tests produced ultimate loads that varied as the square of the tree diameter. However, the ultimate load typically occurred at stump system deformations that were far in excess of that which would be considered failure of a stump anchor. A hyperbolic equation was used to describe the load-deformation behavior of each stump tested and was generalized to describe all the test results. West. J. Appl. For. 2(3):72-80, July 1987.
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Wang, Xiufei, Kun Liu, Mingcai Xu i Hewei Liu. "Plastic Response and Failure of the Cruciform Structure under In-Plane Load". Journal of Marine Science and Engineering 11, nr 7 (24.07.2023): 1478. http://dx.doi.org/10.3390/jmse11071478.
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In this study, a common cruciform structure in ship hulls was designed and experimented with in order to analyze its deformation characteristics under planar collision and quasi-static loading. The mechanical parameters of the materials were determined by performing tensile tests on the plates used in the specimens. The applicability of the EPS, BWH, and RTCL failure criteria in the simulation of compressive structures was investigated by finite element simulation of quasi-static tests and falling weight impact tests. The effects of mesh size on the deformation and impact force of the cruciform structure under plane loading were comparatively analyzed. The results show that under plane loading, the cruciform structure undergoes axial compression deformation first, followed by buckling and wrinkling deformation. Compared with the quasi-static test, the drop hammer impact test showed higher deformation concentration and smaller wrinkle height. Under the same axial deformation condition, the structural resistance of the drop hammer impact test was about 13% higher than that of the quasi-static test. It is worth noting that the RTCL failure criterion is effective in modeling the failure of compressive structures in simulations with structures with different compressive deformations.
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Bacha, Sher, Bingxiang Huang i Haoze Li. "Long-term creep and microscopic deformation mechanisms of sandstone using rock rheology creep equipment and scanning through high-resolution 3D XRM". Journal of Geophysics and Engineering 19, nr 2 (kwiecień 2022): 227–44. http://dx.doi.org/10.1093/jge/gxac004.
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Abstract Since rock is heterogeneous, hence its behavior is always variable. The governing parameters in rock deformations are time, applied load, composition, water content, temperature and loading conditions including confinement and loading rate. Time-dependent deformation study is extremely important for the prevention of hazards such as rockburst, roof fall and collapse. In the current study, sandstone samples from Kouzidong Mine China are analyzed using long-term rheological creep tests and advanced microscopic scanning using 3D X-ray microscopy (XRM). Time is the main governing factor in rock rheological creep study. The current study focuses on the microscopic deformation of selected rock using rheological creep and microscopic analysis. Rock behaves differently under different applied loads; therefore, two different loads are applied on two sandstone samples. Two samples are scanned before and after rheological creep testing. The uniaxial constant load applied on the first sample is 40% of the uniaxial compressive strength of the rock (σ1 = 40%σc) for one month. The behavior of the first sample shows an instantaneous creep and stable creep. The maximum uniaxial strain is 0.0307. The scanning results show evidence of microfractures in sandstone sample 1 at a lower load. There is evidence of grain movement and boundary alteration. The grain movement depends on the bonding between different grains. The second sample is loaded at 50% the of uniaxial compressive strength (σ1 = 50%σc). The maximum uniaxial strain for sample 2 is 0.0408. Creep behavior is the same and the microscopic deformation is enhanced with increasing applied load.
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Muñiz-Menéndez, Mauro, i Ignacio Pérez-Rey. "Intact rock deformation bimodularity: an experimental study". IOP Conference Series: Earth and Environmental Science 1124, nr 1 (1.01.2023): 012041. http://dx.doi.org/10.1088/1755-1315/1124/1/012041.
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Abstract Rock deformability under tensile stresses plays an important role in different scenarios like, e.g., in the mechanical behaviour of roofs in underground openings, hydraulic fracturing, dilatometer tests performed in massive rock masses or in tensile strength tests. Different authors have proved that the tensile deformation modulus of the intact rock can be significantly different than that obtained under compressive load, being this so-called ‘bimodularity’ often ignored. In this work, we present preliminary results from uniaxial compressive and tensile strength tests carried out in three rocks with a testing apparatus recently modified to be able to perform both types of tests. Experimental results show that the deformational behaviour of the rocks studied is dependent on the type of load applied. The present work aims at contributing to a better understanding of the deformational behaviour of rocks, in particular when subjected to uniaxial tensile loads as well as in dealing with future updates of existing test methodologies.
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Sapieta, Milan, Vladimír Dekýš, Ondrej Štalmach, Alžbeta Sapietová i Martin Svoboda. "Detection of Elastic Deformation in Metal Materials in Infrared Spectral Range". Materials 14, nr 18 (17.09.2021): 5359. http://dx.doi.org/10.3390/ma14185359.
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The aim of this work is to verify the presence of deformation in the metal specimen from the material AISI 316L by means of lock-in thermography. The specimen was cyclically loaded by the three-point bending in the fatigue testing machine. A response of the specimen to such excitation can be detected in the infrared spectrum and to determine temperature changes during a loading cycle. By means of the lock-in method, an increased signal to noise ratio (radiation energy detected by an infrared camera) was achieved. Besides, the temperature changes were determined on the basis of amplitudes of radiant energy changes detected by the camera. The temperature change (all radiant energy) corresponds with the first invariant of the tensor of deformation and, after a calculation and regarding the material parameters, also the invariant of the stress tensor. The proportionality between the signal from the camera and the first deformation invariant is achieved if the specimen load is an adiabatic event. This process is achieved by choosing a sufficiently high load frequency. In case of a presence origin of plastic deformations, there takes place only part of radiant energy. When we accept the hypothesis of a presence of just elastic deformations and plastic deformation is also present in the monitored process, then the evaluated thermograms based on the assumption of the presence of elastic deformation present anomalies in a distribution of the determined tensor invariant of deformations. These anomalies are caused by a presence of plastic deformations. Based on the anomalies, plastic deformation can be detected and subsequently analyzed. For the tested specimen and the applied load, the calculation of stress tensor was performed. It confirmed a congruence of results obtained by the analysis of the physical process in the infrared spectrum of the mid-wave infrared camera.
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Hu, Shao Qing, i Bai Tao Sun. "Finite Element Analysis of Air Cooler Using Equivalent Static Method and Response Spectrum Method Respectively". Advanced Materials Research 250-253 (maj 2011): 2955–58. http://dx.doi.org/10.4028/www.scientific.net/amr.250-253.2955.
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Based on the characteristic of cooler frame, the finite element model of air cooler frame is established using ANSYS software. Equivalent static load method and response spectrum method were used for the seismic performance analysis of cooler frame. The equivalent static load is applied at the center of gravity of various masses using MPC184 rigid beam for transferring the load. The deformation and stress of cooler using equivalent static load method are larger than that of cooler using spectrum response method. For this reason, it can be said that the equivalent static load method is more conservative. At last the deformations and stresses of cooler frame using two methods are checked by ASME AG-1 specification. The results showed that the deformation and stress of cooler frame meet the requirements.
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Kushnareva, G., N. Ismailova, I. Radchenko, T. Rabocha i L. Kucherenko. "STRUCTURAL DAMAGE ANALYSIS". Modern technology, materials and design in construction 30, nr 1 (2021): 12–19. http://dx.doi.org/10.31649/2311-1429-2021-12-19.
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The ability of materials to retain the required set of properties under the action of operational loads on the structure is determined by the structural changes that occur under such loads. From the first days of operation, under the influence of force factors, the environment and time, the strength and deformation properties of structures of buildings and structures change. The solution to the main task of construction science - reducing material consumption in construction, is inextricably linked with the need for constant study and refinement of the strength and deformation characteristics of building materials and structures, as well as a change in their bearing capacity over time and an assessment of the working capacity (resource) reserve when setting an external power load. Based on the fundamental position that under the action of a load, a deformation process occurs in the construction material, which is accompanied by irreversible processes of their appearance, development and accumulation of damage to the structure of the material, and, as a result, leads to destruction, we come to the conclusion that it is necessary to carefully study the strength of wooden designs taking into account this phenomenon. There is a need to comprehensively study the issues of damage accumulation in wooden structures under the action of loads and the related processes of changing the cross-sectional area and bearing capacity, to use the research results when calculating structures. This makes it possible to reduce material consumption and make the sections of wooden structures more economical and avoid excessive safety margins. Therefore, an important manifestation is the fixation of cracks and internal interfaces, which allows one to quantify the integral damage of the structure material to predict their safe functioning. The authors considered analytical dependences for the description of disseminated injuries that follow from physical considerations or are constructed from some mechanical models of the process of long-term damage. Three main types of models have been identified: force, deformation and energy. Experimental studies of normal stress diagrams make it possible to visually record the formation of folds in the compressed zone, as well as calculate the value of the instantaneous elastic and viscoelastic components of total deformation. A measure of the accumulation of damage in a material is damage. In this work, the damage was calculated based on the known specific parameters of the material: deflections, relative deformations and changes in the number of acoustic emission signals. The graphs of the dependence of damage on the load were built: - on the development of deflections; - on the development of fibrous deformations; - on the development of deflections and acoustic emission (relative load); - on the development of fibrous deformations (relative load); This scientific work is a logical continuation of previous studies of damage to wooden structures. The article presents the results of experimental studies of the strength, deformability of wooden beams under the influence of a static load. The direction of improving the methodology for designing wooden structures and determining the residual resource has not been reflected in the technical literature. Therefore, it is necessary to conduct a comprehensive study of them.
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Kang, Ting Ting. "Second-Order Effects of Shanxi Tall Steel Framework Sway". Applied Mechanics and Materials 275-277 (styczeń 2013): 1096–99. http://dx.doi.org/10.4028/www.scientific.net/amm.275-277.1096.
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Structure in horizontal wind load produce lateral displacement, vertical load may have caused additional effects due to the lateral displacement and deformation of the cumulative increase leads to structural instability collapse. Due to the characteristics and problems of the structure, utilizing SAP2OOO finite element software, this paper consider the deformation of the lateral displacement of the second-order effects under wind loads and loads of the Shanxi Taiyuan Xiaodian a tall steel frame structure.
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Long, Lin, Zhida Li i Yunyu Li. "Investigation of an Empirical Creep Constitutive Model of Changsha Red Loam". Buildings 13, nr 4 (18.04.2023): 1064. http://dx.doi.org/10.3390/buildings13041064.
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To describe and predict the creep deformation of Changsha red loam (including sandy soil and silty clay) in China, an empirical creep model was proposed based on a laboratory consolidation compression test. Two classical soil layers were sampled from the deep foundation pit site and fourteen samples were designed for tests under different loading conditions. Results show that the deformation process illustrates deceleration and stabilization creep with its vertical load lower than 500 kPa, while it may illustrate acceleration with its vertical load higher than 500 kPa. By analyzing the experimental results, the empirical creep model of the red loam was established. Adopting the model to predict the deformation of red loam shows the prediction curves match the actual situation, proving that the model plays a significant role in predicting the creep deformation of Changsha red loam.
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Mei, Yi, Fang Ping Wang, Qiao Ying Liu i Yu Tao Mao. "Finite Element Analysis on Thermal Structures of Heavy Machinery Gearbox". Advanced Materials Research 228-229 (kwiecień 2011): 651–55. http://dx.doi.org/10.4028/www.scientific.net/amr.228-229.651.
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To solve the thermal deformation caused by thermal load of heavy machinery gearbox, it is established that coupled analysis model to carry out the analysis on box structure's thermal characteristic by using the finite element thermal structure coupled analysis. The model figures out the steady-state temperature distribution of the box, the results will be the boundary condition for box thermal structural coupled analysis. It is calculated which stress distribution and displacement cloud pictures of the box under the interaction of thermal and structural load. The results show that deformation of the heavy machinery gearbox is cased by structural loads and thermal loads. And the thermal load is an important factor that controls box deformation to ensure the accuracy and reliability of heavy gear transmission, which can not be ignored.
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Kerr, Hamish A., Peter G. Gerbino, Ricardo Soto, David Zurakowski i John A. Muller. "Load-deformation Characteristics Of The Patella". Medicine & Science in Sports & Exercise 39, Supplement (maj 2007): S472. http://dx.doi.org/10.1249/01.mss.0000274870.24509.28.
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Denisov, G. G., i V. V. Novikov. "Membrane deformation by a moving load". Journal of Applied Mathematics and Mechanics 61, nr 4 (styczeń 1997): 627–32. http://dx.doi.org/10.1016/s0021-8928(97)00080-4.
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Simons, J. W., A. Dalal i D. A. Shockey. "Load-Deformation Behavior of Nitinol Stents". Experimental Mechanics 50, nr 6 (26.03.2010): 835–43. http://dx.doi.org/10.1007/s11340-010-9341-7.
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Bradby, J. E., J. S. Williams, J. Wong-Leung, M. V. Swain i P. Munroe. "Mechanical deformation in silicon by micro-indentation". Journal of Materials Research 16, nr 5 (maj 2001): 1500–1507. http://dx.doi.org/10.1557/jmr.2001.0209.
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The mechanical deformation of crystalline silicon induced by micro-indentation has been studied. Indentations were made using a variety of loading conditions. The effects on the final deformation microstructure of the load–unload rates and both spherical and pointed (Berkovich) indenters were investigated at maximum loads of up to 250 mN. The mechanically deformed regions were then examined using cross-sectional transmission electron microscopy (XTEM), Raman spectroscopy, and atomic force microscopy. High-pressure phases (Si-XII and Si-III) and amorphous silicon have been identified in the deformation microstructure of both pointed and spherical indentations. Amorphous Si was observed using XTEM in indentations made by the partial load–unload method, which involves a fast pressure release on final unloading. Loading to the same maximum load using the continuous load cycle, with an approximately four times slower final unloading rate, produced a mixture of Si-XII and Si-III. Slip was observed for all loading conditions, regardless of whether the maximum load exceeded that required to induce “pop-in” and occurs on the {111} planes. Phase transformed material was found in the region directly under the indenter which corresponds to the region of greatest hydrostatic pressure for spherical indentation. Slip is thought to be nucleated from the region of high shear stress under the indenter.
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Xu, Pengfei, Tao Jiang, Chuanyin Zhang, Ke Shi i Wanqiu Li. "Recovering Regional Groundwater Storage Anomalies by Combining GNSS and Surface Mass Load Data: A Case Study in Western Yunnan". Remote Sensing 14, nr 16 (18.08.2022): 4032. http://dx.doi.org/10.3390/rs14164032.
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The redistribution of surface mass (e.g., atmosphere, soil water, oceans, and groundwater) can cause load responses, resulting in vertical deformations of the crust. Indeed, the global navigation satellite system (GNSS)-based continuously operating reference stations (CORS) are able to accurately measure the vertical deformation caused by surface mass loads. In this study, the CORS was used to invert groundwater storage anomalies (GWSA), represented by the equivalent water height (EWH), after removing the effect of the non-groundwater surface mass load (atmospheric, groundwater, and non-tidal oceanic loads) from the vertical deformation monitored by CORS. In addition, the global and regional high-resolution surface mass models were combined to calculate the high-precision load deformation field in in western Yunnan using the remove–restore method, thereby obtaining more accurate surface mass load data and improving the accuracy of the inverted GWSA results. In order to assess the feasibility of the CORS inversion for the GWSA used, 66 CORS stations in western Yunnan Province were considered, presenting weekly GWSA data from 10 January 2018 to 31 December 2020. The results revealed significant seasonal variation in GWSA in the study area, showing an amplitude range of −200–200 mm. This approach is based on the already-established CORS network without requiring additional set-up costs. In addition, the reliability of CORS inverse results was assessed using Gravity Recovery and Climate Experiment (GRACE) inverse results and actual groundwater monitoring data. According to the obtained results, GWSA can be monitored by both CORS and GRACE data; however, CORS provided a more effective spatiotemporal resolution of GWSA. Therefore, the CORS network combined with surface mass load data is able to effectively monitor the spatiotemporal dynamics of GWSA in small-scale areas and provides important references for the study of hydrology.
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Zehsaz, Mohammad, Farid Vakili Tahami i Yasser Ashraf Gandomi. "The Plastic Work Curvature Criterion in Evaluating Gross Plastic Deformation for Pressure Vessels with Conical Heads". Applied Mechanics and Materials 50-51 (luty 2011): 93–99. http://dx.doi.org/10.4028/www.scientific.net/amm.50-51.93.
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Conical shells are often joined to cylindrical shells and under internal pressure, the intersection between the large end of a cone and a cylinder is subjected to a large circumferential compressive stresses which can lead to its failure by whether axi-symmetric gross plastic deformation involving excessive inward deformations or non-symmetric buckling which accompanies by circumferential waves around the intersection. In Pressure Vessel Design by Analysis, the designer is required to address both these behavior modes when specifying the allowable static load. In this paper, plastic collapse or gross plastic deformation load is evaluated for a typical pressure vessel with conical head using plastic work curvature criterion and the results are compared with other criteria suggested by international standards such as ASME. The plastic work curvature criterion is based on the plastic work dissipated in the structure as loading progresses and may be used for structures subject to a single load or a combination of multiple loads. The results of analyzing using this new criterion show that the plastic collapse load given by the plastic work curvature criterion is robust and consistent and is in the close agreement with the results from international codes. The most significant aspect of the proposed method in which plastic work curvature criterion has been used is that the plastic collapse loads are determined purely by the inelastic response of the structure and therefore they are not influenced by the initial elastic response: a problem with some other established plastic criteria. The results also show that the design load is mostly limited by the formation of an axi-symmetric gross plastic deformation in the intersection of the vessel prior to the formation of non-symmetric buckling modes
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Bohdziewicz, Jerzy, i Gabriel Czachor. "Dissipation of Energy in Tissues of Berry Fruit of Selected Plants Species under Cyclic Load Conditions". Agricultural Engineering 20, nr 4 (1.12.2016): 5–14. http://dx.doi.org/10.1515/agriceng-2016-0059.
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Abstract Dissipation hypothesis of energy under cyclic loads conditions was used to characterize the behavior of berry fruit. The possibility of dissipation of energy as a result of plastic deformations (Dawidenkow hypothesis) or visco-elastic deformations (Voigt hypothesis) was considered. Tests of hysteresis of whole fruit squeezed among two rigid plates for various levels of load and with various speeds of deformation of samples for two directions of load application were conducted for verification of the usefulness of both hypotheses. The strength tests were preceded by the test of hysteresis, the mass and the geometry of fruit were determined additionally as well as conventional density and moisture was counted. A mutual relation of average values of the coefficients of elasticity EC was accepted as the measure of dissipation of energy as a result of changes in the angle of inclination of the curve in the springy return phase. Voigt hypothesis was confirmed as useful within the range of small speeds of deformation and lack of usefulness of the Dawidenkow hypothesis was proved.
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ZENKOUR, ASHRAF M. "THE EFFECT OF TRANSVERSE SHEAR AND NORMAL DEFORMATIONS ON THE THERMOMECHANICAL BENDING OF FUNCTIONALLY GRADED SANDWICH PLATES". International Journal of Applied Mechanics 01, nr 04 (grudzień 2009): 667–707. http://dx.doi.org/10.1142/s1758825109000368.
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A thermomechanical bending analysis for a simply supported, rectangular, functionally graded material sandwich plate subjected to a transverse mechanical load and a through-the-thickness thermal load is presented using the refined sinusoidal shear deformation plate theory. The present shear deformation theory includes the effect of both shear and normal deformations and it is simplified by enforcing traction-free boundary conditions at the plate faces. Material properties and thermal expansion coefficient of the sandwich plate faces are assumed to be graded in the thickness direction according to a simple power-law distribution in terms of the volume fractions of the constituents. The core layer is still homogeneous and made of an isotropic material. The equilibrium equations of different sandwich plates are given based on various plate theories. A number of examples are solved to illustrate the numerical results concern thermo-mechanical bending response of functionally graded rectangular sandwich plates. The influences played by transversal shear and normal deformations, plate aspect ratio, side-to-thickness ratio, volume fraction distributions, and thermal and mechanical loads are investigated.
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Castañeda Villalba, Jaime Andres, Sara Aida Rodriguez Pulecio i John Jairo Coronado Marin. "Fatigue behavior evaluation in Fe-20Mn-3Al-0.9C alloys by dynamic nanoindetation". Ingenieria Solidaria 19, nr 2 (4.08.2023): 1–15. http://dx.doi.org/10.16925/2357-6014.2023.02.07.
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The fatigue response by applying cyclic loads on individual grains using monotonic and cyclic nanoindetation to analyze the effect on load or displacement control in an austenitic Fe-20Mn-3Al-09C alloy were analyzed. The material response to the cycles considering the load control and the displacement control to properties such as hardness, elastic's modulus, and contact stiffness, was studied by analyzing the load-unload curves (P-h). The material softening Analysis showed that these properties decrease with increasing cycles due to the activation of deformation mechanisms. The elasticity's Modulus and hardness values for monotonic loads in load control presented values close to those reported in the literature. On the other hand, in displacement control, the values were lower. In load and displacement control mode, the first two cycles presented no overlap between unloading and loading between cycles, due to large irreversible plastic deformation and low elastic recovery after unloading. In the subsequent cycles, overlaps between the hysteresis curves were predominant, due to the activation of the deformation mechanisms.
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Kim, Seung Gyun, Eun Seong Yu, Jong Mo Lee, Seung Jae Moon, Ki-Yong Lee i Byung Seong Bae. "P‐144: Late‐News Poster: Evaluation for Flexible Substrates According to the Number of Rollings". SID Symposium Digest of Technical Papers 54, nr 1 (czerwiec 2023): 1532–35. http://dx.doi.org/10.1002/sdtp.16883.
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A scratch test was performed to evaluate the substrate deformation according to the number of rolling times for the rollable display. For polyimide and thermal plastics polyurethane, the critical loads are analyzed according to the number of rolling times. As increasing the load, friction coefficients were measured during the scratch on films. The effect of substrate rolling times on plastic n and elastic deformations were evaluated.