Journal articles: 'Trajectory deformation'

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Fraichard, Thierry, and Vivien Delsart. "Navigating Dynamic Environments with Trajectory Deformation." Journal of Computing and Information Technology 17, no. 1 (2009): 27. http://dx.doi.org/10.2498/cit.1001157.

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Gubanova, Alexandra A. "Investigation of stationary trajectories with associated milling by spur gears." MATEC Web of Conferences 226 (2018): 02004. http://dx.doi.org/10.1051/matecconf/201822602004.

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When milling in a steady state, unlike, for example, turning, there are periodic elastic deformation displacements of the tool relative to the workpiece along the machining path. Instead of an equilibrium point, we consider a certain closed trajectory of elastic deformations. This is the trajectory to which all the trajectories approach asymptotically, while forces and deformations that mutually affect each other through the mechanism of changing the area of the cut-off layer are redistributed. The article proposes a mathematical apparatus and algorithms for calculating the trajectory of establishing a stationary state. The case of milling with spur mills is considered. A mathematical description of the “basic” dynamic model of the associated milling by the side teeth of the end mills for the complete non-stationary nonlinear connection formed by the milling process is presented. It differs from known models by considering spatial oscillations, taking into account the dependence of forces on the cutting speeds, taking into account the rates of elastic deformation displacements, taking into account the retardation of forces with respect to deformation displacements, and also by nonlinear damping caused by forces acting on the trailing edge of the tool. In addition, periodic changes in the parameters and the formation of the surface at the previous contact of the tooth are taken into account.

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Mei, Jiangping, Fan Zhang, Jiawei Zang, Yanqin Zhao, and Han Yan. "Trajectory optimization of the 6-degrees-of-freedom high-speed parallel robot based on B-spline curve." Science Progress 103, no. 1 (October 10, 2019): 003685041988011. http://dx.doi.org/10.1177/0036850419880115.

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According to the problem that the existing high-speed parallel robot cannot satisfy the operation requirements of non-planar industrial production line, a 6-degrees-of-freedom high-speed parallel robot is proposed to carry out the kinematic and dynamic analyses. Combining with the door-type trajectory commonly used by the parallel robot, it adopts 3-, 5-, and 7-time B-spline curve motion law to conduct the trajectory planning in operation space. Taking the average cumulative effect of joint jerky as the optimization target, a trajectory optimization method is proposed to improve the smoothness of robot end-effector motion with the selected motion law. Furthermore, to solve the deformation problem of the horizontal motion stage of the trajectory, a mapping model between the control point subset of B-spline and the motion point subset of trajectory is established. Based on the main diagonally dominant characteristic of the coefficient matrix, the trajectory deformation evaluation index is constructed to optimize the smoothness and minimum deformation of the robot motion trajectory. Finally, compared to without the optimization, the maximum robot joint jerk decreases by 69.4% and 72.3%, respectively, and the maximum torque decreases by 51.4% and 38.9%, respectively, under a suitable trajectory deformation.

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Ario, Takahiro, and Ikuo Mizuuchi. "Planning the Shortest Carrying Trajectory Including Path and Attitude Change Considering Gripping Constraints." Journal of Robotics and Mechatronics 34, no. 3 (June 20, 2022): 607–14. http://dx.doi.org/10.20965/jrm.2022.p0607.

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Carrying gripped objects at high speed can lead to gripping failure owing to loads applied to the gripper by its acceleration. When carrying an object at high speed, it is important to carry it with accelerations at which gripping is maintained. Previously proposed methods generated the shortest carrying trajectory for a predetermined trajectory path. In this study, focusing on the object-carrying trajectory and the hand attitude of the gripper, we propose a method to generate the shortest carrying trajectory by varying the state quantities. The proposed method considers the gripping force and the deformation of the gripper. During planning, we estimated the deformation volume of the gripper from its inputs and generated the shortest carrying trajectory with the allowable force and deformation values as constraints. Using the proposed method, we generated a trajectory capable of carrying objects in a shorter time (0.28 times) than in a straight-line trajectory and conducted experiments with a robot arm. The trajectory was generated while keeping the hand attitude unchanged. Through experiments, we have proved the effectiveness of keeping objects gripped on the generated shortest carrying trajectory. Compared with a success ratio of 0.47 in keeping objects gripped on the trajectory with the same time as the generated trajectory, the success ratio on the generated trajectory is as high as 1.0.

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Young Sung Ghim and John H. Seinfeld. "Trajectory models and the deformation of air parcels." Atmospheric Environment (1967) 22, no. 1 (January 1988): 25–29. http://dx.doi.org/10.1016/0004-6981(88)90296-x.

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Piras, Paolo, Valerio Varano, Maxime Louis, Antonio Profico, Stanley Durrleman, Benjamin Charlier, Franco Milicchio, and Luciano Teresi. "Transporting Deformations of Face Emotions in the Shape Spaces: A Comparison of Different Approaches." Journal of Mathematical Imaging and Vision 63, no. 7 (May 18, 2021): 875–93. http://dx.doi.org/10.1007/s10851-021-01030-6.

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AbstractStudying the changes of shape is a common concern in many scientific fields. We address here two problems: (1) quantifying the deformation between two given shapes and (2) transporting this deformation to morph a third shape. These operations can be done with or without point correspondence, depending on the availability of a surface matching algorithm, and on the type of mathematical procedure adopted. In computer vision, the re-targeting of emotions mapped on faces is a common application. We contrast here four different methods used for transporting the deformation toward a target once it was estimated upon the matching of two shapes. These methods come from very different fields such as computational anatomy, computer vision and biology. We used the large diffeomorphic deformation metric mapping and thin plate spline, in order to estimate deformations in a deformational trajectory of a human face experiencing different emotions. Then we use naive transport (NT), linear shift (LS), direct transport (DT) and fanning scheme (FS) to transport the estimated deformations toward four alien faces constituted by 240 homologous points and identifying a triangulation structure of 416 triangles. We used both local and global criteria for evaluating the performance of the 4 methods, e.g., the maintenance of the original deformation. We found DT, LS and FS very effective in recovering the original deformation while NT fails under several aspects in transporting the shape change. As the best method may differ depending on the application, we recommend carefully testing different methods in order to choose the best one for any specific application.

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Li, Huifang, and Dariusz Ceglarek. "Optimal Trajectory Planning For Material Handling of Compliant Sheet Metal Parts." Journal of Mechanical Design 124, no. 2 (May 16, 2002): 213–22. http://dx.doi.org/10.1115/1.1463035.

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One of the most critical issues in the material handling of compliant objects is excessive part deformation. The deformation of compliant sheet metal parts during the handling process can significantly impact both part dimensional quality and production rate. Increasing production rate while maintaining part quality requires an optimal design of the part transfer trajectory. This paper describes a new methodology of time-optimal trajectory planning for compliant parts by discretizing the part transfer path into N segments that have equal horizontal distance and by approximating the trajectory as having piecewise constant acceleration that can only change its value at the end of each segment. The contribution of the methodology is that part deformation determined by transfer velocity and acceleration is considered as a nonlinear constraint, which is obtained from FEA simulation and model fitting. Part permanent deformation, trajectory smoothness, and static obstacle avoidance are also considered. The methodology is validated by simulations at different motion conditions and obstacle configurations. This paper addresses the lack of current design guidelines for material handing development and simultaneously provides a mathematical tool to significantly enhance the production efficiency in manufacturing of compliant sheet metal parts.

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Pham, Quang-Cuong, and Yoshihiko Nakamura. "A New Trajectory Deformation Algorithm Based on Affine Transformations." IEEE Transactions on Robotics 31, no. 4 (August 2015): 1054–63. http://dx.doi.org/10.1109/tro.2015.2450413.

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Grozav, Sorin Dumitru, Vasile Adrian Ceclan, Antoniu Turcu, and Ovidiu Vasile Oprea. "Kinematic Process Plastic Cold Orbital Forming." Applied Mechanics and Materials 808 (November 2015): 98–103. http://dx.doi.org/10.4028/www.scientific.net/amm.808.98.

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In the paper before you, the authors study the kinematics of the orbital deformation process on the base of the trajectory equation of the mobile element of the machine. Also, the authors show that the trajectory is a closed cycle curve with a finite number of lobes. Relations and charts are presented for the calculation of the number of lobes and their width depending on the machine setting. The upper mold half trajectory choice (active tool) to match the best part deformed kinematics requires detailed knowledge of orbital plastic deformation process, something which develops in the present paper.

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Shin, J., T. W. Cornelius, S. Labat, F. Lauraux, M. I. Richard, G. Richter, N. P. Blanchard, D. S. Gianola, and O. Thomas. "In situ Bragg coherent X-ray diffraction during tensile testing of an individual Au nanowire." Journal of Applied Crystallography 51, no. 3 (May 18, 2018): 781–88. http://dx.doi.org/10.1107/s1600576718004910.

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Systematic tensile tests were performed on single defect-free 〈110〉 Au nanowires grown by physical vapor deposition while simultaneously recording three-dimensional Bragg peaks using coherent X-rays. The trajectory of three-dimensional Bragg peaks in reciprocal space during tensile testing allowed for measurements of the evolution of strains and rotations of the nanowire, thus sensitively uncovering the full deformation geometry of the nanowire. The transition from elastic to plastic deformation is accompanied by rotations of the nanowire as quantified by analysis of the motion of Bragg peaks, showing the importance of boundary conditions in interpreting nanoscale mechanical deformations.

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Jiang, Shan, Zhiliang Su, Zhiyong Yang, Jun Liu, and Zhenxing Liu. "THE POTENTIAL FIELD-BASED TRAJECTORY PLANNING FOR NEEDLE INSERTION IN A SOFT-TISSUE MODEL." Biomedical Engineering: Applications, Basis and Communications 25, no. 01 (February 2013): 1350017. http://dx.doi.org/10.4015/s1016237213500178.

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This paper presents a 3D dynamic trajectory planning method for the insertion of a rigid needle into soft tissue. The optimal needle tip orientation was calculated in which applying an artificial potential field method to determine the 3D distribution of repulsive and attractive forces surrounding the target object and adjacent obstacles, e.g. bones, nerves, or arteries. Soft-tissue deformation occurs dynamically and continuously during the needle insertion. The trajectory planning was therefore temporally discretized, and the compartment searching method used in each time step. This trajectory planning method was then validated by a dynamic finite element method (FEM) simulation. The dynamic finite element model is built for the important displacement parameters of deformation node in needle insertion process. The Mooney–Rivlin material model combined with solid cubic element and an explicit center differencing scheme was used to compute the soft-tissue deformation at each time step and dynamically identify the target and obstacle positions. The proposed trajectory planning method can optimize the insertion path to achieve the target position while avoiding obstacles.

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Pan, Yan Hong. "Numerical Simulation of the Basketball Flight Trajectory Based on FLUENT Fluid Solid Coupling Mechanics." Applied Mechanics and Materials 651-653 (September 2014): 2347–51. http://dx.doi.org/10.4028/www.scientific.net/amm.651-653.2347.

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The calculation of basketball trajectory involves the elastic-plastic mechanics and aerodynamics theory. Besides the deformation of basketball flight, the flight is a complex fluid solid coupling process. If wanting to simulate the flight trajectory of basketball accurately, it must consider the effect of flow field and solid fluid solid coupling field. In order to calculate the flight trajectory of basketball accurately and improve basketball shooting speed and posture training efficiency in the training process, this paper uses the FLUENT to simulate the basketball flight trajectory. Combined with the aerodynamic theory we established the mathematical model of basketball flight. Through the numerical simulation we calculate the velocity field and the monitoring point deformation curve of basketball flight, it provides a new method for computer technical training for basketball players.

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Zhang, Jun. "Study on Dynamics Model of Solid Trajectory Analysis and Pneumatics Based on Space-Time Four-Dimensional Data." Applied Mechanics and Materials 556-562 (May 2014): 3856–59. http://dx.doi.org/10.4028/www.scientific.net/amm.556-562.3856.

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In this paper we use elastic-plastic mechanics and air dynamic to establish the mathematical model of badminton flight trajectory and deformation, and use the ANSYS software to do simulation on badminton flight process, and obtain the flight path and deformation of badminton. In order to analyze the badminton four-dimensional space-time data, we establish the one-dimensional time measurement, and use one-dimensional time transient stress to establish flight trajectory and deformation, and design the four-dimensional space-time steady-state simulation process. Through calculation we eventually get the force of badminton flight process and deformation nephogram. Comparing four times results of numerical simulation results, the mathematical model of this design model meets the design requirements. It provides technical reference for badminton athlete's training and teaching.

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Ni, Jinlu, Jiangping Mei, and Weizhong Hu. "A hierarchical approach for rigid-body dynamics model simplification of a high-speed parallel robot by considering kinematics performance." Science Progress 104, no. 4 (October 2021): 003685042110630. http://dx.doi.org/10.1177/00368504211063072.

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Considering the real-time control of a high-speed parallel robot, a concise and precise dynamics model is essential for the design of the dynamics controller. However, the complete rigid-body dynamics model of parallel robots is too complex for online calculation. Therefore, a hierarchical approach for dynamics model simplification, which considers the kinematics performance, is proposed in this paper. Firstly, considering the motion smoothness of the end-effector, trajectory planning based on the workspace discretization is carried out. Then, the effects of the trajectory parameters and acceleration types on the trajectory planning are discussed. But for the fifth-order and seventh-order B-spline acceleration types, the trajectory will generate excessive deformation after trajectory planning. Therefore, a comprehensive index that considers both the motion smoothness and trajectory deformation is proposed. Finally, the dynamics model simplification method based on the combined mass distribution coefficients is studied. Results show that the hierarchical approach can guarantee both the excellent kinematics performance of the parallel robot and the accuracy of the simplified dynamics model under different trajectory parameters and acceleration types. Meanwhile, the method proposed in the paper can be applied to the design of the dynamics controller to enhance the robot's performance.

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Hua, RuHao, ChengXi Zhao, ZhengYin Ye, and YueWen Jiang. "Effect of elastic deformation on the trajectory of aerial separation." Aerospace Science and Technology 45 (September 2015): 128–39. http://dx.doi.org/10.1016/j.ast.2015.04.015.

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Aslanov, Jamaladdin Nuraddin, Sevinc Malik Abasova, and Zenfira Seydi Huseynli. "THE MANAGEMENT OF CHARACTERISTICS OF THE NEW TWO-LAYER RUBBER MATRIX SEALS." EUREKA: Physics and Engineering 5 (September 30, 2020): 60–68. http://dx.doi.org/10.21303/2461-4262.2020.001401.

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Rubber seals for closing devices operating in cold climates degrade quickly in aggressive environments at very low temperatures. As a result, leaks and failures occur in the closure devices. Therefore, there is a great need to develop a new model of rubber seals and develop their scientific basis. The article is devoted to increasing the sealing effect of rubber seals of machines and equipment, including closures, by introducing the anisotropy of the rubber matrix into its structure with control of the characteristics of hard closures obtained from rubber. For this purpose, new models of the gate valve design were obtained and new models of two-layer panel seals based on a modified rubber elastomer matrix are applied to these structures. For this, a test program is carried out in the form of an analytical trajectory of large, medium and small constant curves in two closed forms based on characteristic deformations to study the anisotropy of matrix deformations. It is found that the eigenvector of the deformation anisotropy of the matrix is not in the load trajectory before it collapses, it arises with a delay. This delay slows down the rate of destruction. This property of deceleration of the main eigenvector of the deformation anisotropy of the matrix is subjected to a very complex loading of the initial fields, in the latter sections it is also observed in samples No. 2, No. 3, tested along the trajectory of linear loading. This delay slows down the destruction rate. Thus, the direction of the deceleration property of the main eigenvector can be considered quite common. This leads to an increase in its resistance to wear in a highly aggressive environment

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Proskokov, A. V., A. V. Filippov, and V. V. Gorbatenko. "Experimental Study of Plastic Deformation Intensity in Cutting Zone." Applied Mechanics and Materials 770 (June 2015): 200–204. http://dx.doi.org/10.4028/www.scientific.net/amm.770.200.

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The paper considers the intensity degree of a plastic shear deformation ei when cutting, the results of experimental studies that determine a travel trajectory of a cutting material layer through a plastic deformation zone in a chipping area and comparative analysis of deformation conditions of a sample material machined by various tool rake angles (γ=0o and γ=15o).

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Zubchaninov, V. G., A. A. Alekseev, and V. I. Gultiaev. "The effect of replacing non-analytic trajectories with break points on smooth paths to the complexity of deformation and loading processes of materials." PNRPU Mechanics Bulletin, no. 2 (December 15, 2020): 52–63. http://dx.doi.org/10.15593/perm.mech/2020.2.05.

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This article is devoted to an experimental study of the effect of rounding off corner points of two-link strain trajectories on complex loading processes during elastoplastic deformation of materials. Replacing corner points in their vicinity with local sections of circles allows a nonanalytic trajectory to be replaced with a smooth trajectory. Experimental studies were performed on thin-walled tubular specimens of the low-carbon steel St3 on an SN-EVM automated testing system. The loading programs for tubular specimens were set in the Ilyushin's deviatoric strain space. The rounding of the corner point of a two-link strain trajectory with an angle of 90° between the branches by arcs of circles with curvatures of 200, 400, as well as the rounding of the corner point of a two-link strain trajectory with an angle of 135° between the branches by arcs with curvatures of 400, 800 are considered. The experimental data characterizing the vector and scalar properties of the material are presented. The experimental data show that the effect of complex loading on the relationship between stresses and strains in a curved section is not immediately apparent. In the curved section, the magnitude of the stress vector modulus first increases, and then decreases with the formation of stress dives. The minimum point of the stress dive is located on the next straight branch of the strain trajectory. In the curvilinear section, the angle of delay increases, and in the next straight branch it decreases, and with the increase of the strain it tends to be zero. The rate of decrease of the angle of delay depends little on the differences in the geometry of the previous history of strain trajectory. In the second straight branch, the experimental results for a smooth and original two-link strain trajectories become little distinguishable from each other. Thus, replacing the original non-analytical strain trajectory to a smooth trajectory affects the complexity of the process of deformation and loading of the materials only in the vicinity of the corner point. This circumstance can be taken into account when numerically modeling the processes of elastoplastic deformation of materials and integrating the defining relations, replacing nonanalytic trajectories with smooth ones. This can be taken into account in the numerical calculation of elastic-plastic deformation and integration of constitutive relations, replacing non-analytical strain trajectories by smooth ones.

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Abbas, Laith K., Dongyang Chen, and Xiaoting Rui. "Numerical Calculation of Effect of Elastic Deformation on Aerodynamic Characteristics of a Rocket." International Journal of Aerospace Engineering 2014 (2014): 1–11. http://dx.doi.org/10.1155/2014/478534.

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The application and workflow of Computational Fluid Dynamics (CFD)/Computational Structure Dynamics (CSD) on solving the static aeroelastic problem of a slender rocket are introduced. To predict static aeroelastic behavior accurately, two-way coupling and inertia relief methods are used to calculate the static deformations and aerodynamic characteristics of the deformed rocket. The aerodynamic coefficients of rigid rocket are computed firstly and compared with the experimental data, which verified the accuracy of CFD output. The results of the analysis for elastic rocket in the nonspinning and spinning states are compared with the rigid ones. The results highlight that the rocket deformation aspects are decided by the normal force distribution along the rocket length. Rocket deformation becomes larger with increasing the flight angle of attack. Drag and lift force coefficients decrease and pitching moment coefficients increase due to rocket deformations, center of pressure location forwards, and stability of the rockets decreases. Accordingly, the flight trajectory may be affected by the change of these aerodynamic coefficients and stability.

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Fang, Qiang, Weidong Chen, Anan Zhao, Changxi Deng, and Shaohua Fei. "Control system designing for correcting wing–fuselage assembly deformation of a large aircraft." Assembly Automation 37, no. 1 (February 6, 2017): 22–33. http://dx.doi.org/10.1108/aa-01-2016-006.

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Purpose In aircraft wing–fuselage assembly, the distributed multi-point support layout of positioners causes fuselage to deform under gravity load, leading to assembly difficulty and assembly stress. This paper aims to propose a hybrid force position control method to balance aerodynamic shape accuracy and deformation of assembly area, thereby correcting assembly deformation and reducing assembly stress. Design/methodology/approach Force and position control axes of positioners are selected based on screw theory and ellipsoid method. The position-control axes follow the posture trajectory to align the fuselage posture. To exert force on the fuselage and correct the deformations, the force-control axes follow the contact force derived by using orthogonal experiments and partial least squares regression (PLSR). Finite element simulation and one-dimension deformation correction experiment are conducted to verify the validity of this method. Findings Simulation results indicate that hybrid force position control method can correct assembly deformation and improve the wing–fuselage assembly quality significantly. Experiment on specimen verifies the effect of this method indirectly. Originality/value The proposed method gives a solution to solve the deformation problem during aircraft wing-fuselage assembly, thereby reducing assembly stress and improving assembly quality.

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Ni, Bao-yu, A.-man Zhang, Xiong-liang Yao, and Bin Wang. "Numerical simulation of trajectory and deformation of bubble in tip vortex." Applied Mathematics and Mechanics 33, no. 6 (June 2012): 701–16. http://dx.doi.org/10.1007/s10483-012-1581-9.

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Hu, Xian Ming, E. Chuan Yan, Kun Lv, and Ting Ting Zhang. "Fractal Characteristics of Motion Trace Curve of Landslide Monitoring Points." Applied Mechanics and Materials 90-93 (September 2011): 1285–90. http://dx.doi.org/10.4028/www.scientific.net/amm.90-93.1285.

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According to the analysis of the landslide monitoring data, it is revealed that the amount of the cumulative displacement of the landslide depends on the monitoring cycle. And the trajectory curve of monitoring point has the fractal characteristics. The fractal dimension of the landslide internal points’ movement direction is various with the landslide development, which is decreased from the generation to the deformation and then to the damage. Meanwhile, based on the fractal boxing counting theorem, the program in Matlab is created to calculate the box dimension of the curve. Take a reviving landslide in Three-Gorge as an example, the fractal dimensions of the surface GPS monitoring points’ trajectory curves from 2007 to 2009 are obtained, and the dimension of each point is close to 1. The result indicates that this landslide is in the plastic deformation stage. It is the same with the landslide actual deformation. Therefore, the fractal theory has a great significance in the effective use of the monitoring data, the reorganization of the evolving stage and the prediction of the deformation trend for the landslide.

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Kondratev, N. S., P. V. Trusov, and A. N. Podsedertsev. "MULTILEVEL PHYSICAL-ORIENTED MODEL: APPLICATION TO THE DESCRIPTION OF THE INITIAL STAGE OF DYNAMIC RECRYSTALLIZATION OF POLYCRYSTALS." Problems of Strength and Plasticity 83, no. 4 (2021): 451–61. http://dx.doi.org/10.32326/1814-9146-2021-83-4-451-461.

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Thermomechanical processing of metals and alloys is accompanied by deep changes of the material structure (including grain structure), which determines physical and mechanical properties and the working characteristics of products made from them. Its change is possible due to mechanical (fragmentation process) and/or temperature (recrystallization process) influences. Because of this, an urgent task is to create mathematical models that allow describing changes in the material structure and the stress-strain state under thermomechanical treatment. For this purpose, the multilevel physically oriented model was developed for researching inelastic deformation of polycrystals. The problem of modeling two stages deformation of a polycrystalline copper sample was formulated. At the first stage, preliminary cold intense plastic deformation under complex loading was investigated. Two variants of preliminary deformation were considered. They were homogeneous deformation corresponding to equal-channel angular compression (ECUP), and deformation with closed deformation trajectory. At the second stage, uniaxial high-temperature deformation was considered prior to the beginning of an intensive dynamic recrystallization. The paper describes the method for estimating the recrystallized material volume fraction within the framework of the multilevel model. The influence of the deformation temperature, the preliminary deformation, the deformation texture, and the average angle of mutual misorientation of neighboring grains on recrystallization was investigated. These parameters determine the development of dynamic recrystallization, since its main physical cause is the difference in stored energy between neighboring grains. It was shown that the developed mathematical model is suitable for describing the thermal activation of dynamic recrystallization at temperatures in the range of 0,4–0,7 homologous temperature. The deformation trajectory complexity determines the type of deformation texture, its “sharpness” or “dispersion”, the angles of neighboring grains mutual misorientation. The results of computational experiments are presented. According to the proposed method, the deformation at the high-temperature stage is determined, at which the intensive migration of new grains begins during recrystallization.

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Oka, M., H. Kamisaka, T. Fukumura, and T. Hasegawa. "DFT-based ab initio MD simulation of the ionic conduction in doped ZrO2 systems under epitaxial strain." Physical Chemistry Chemical Physics 17, no. 43 (2015): 29057–63. http://dx.doi.org/10.1039/c5cp03238e.

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Гультяев, Вадим Иванович, Владимир Георгиевич Зубчанинов, Андрей Алексеевич Алексеев, and Иван Александрович Саврасов. "Experimental investigation of steel 45 along some smooth curvilinear strain trajectory." Вестник Чувашского государственного педагогического университета им. И.Я. Яковлева. Серия: Механика предельного состояния, no. 3(49) (December 29, 2021): 33–41. http://dx.doi.org/10.37972/chgpu.2021.49.3.004.

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В работе представлены экспериментальные результаты деформирования тонкостенного трубчатого образца по гладкой криволинейной траектории деформирования постоянной кривизны, в которой на каждом участке изменяется знак кривизны и смещается ее центр. Экспериментальное исследование выполнено на автоматизированном расчетноэкспериментальном комплексе СН-ЭВМ в девиаторном пространстве деформаций А.А. Ильюшина (жесткое нагружение) при одновременном комбинированном действии на тонкостенный трубчатый образец растяжения-сжатия и кручения. Исследованы скалярные и векторные свойства материала стать 45. Показано, что экспериментальные диаграммы, характеризующие скалярные и векторные свойства материала носят колебательный характер. The paper presents experimental results of deformation of a thin-walled tubular specimen along a smooth curvilinear strain trajectory of constant curvature, in which the sign of curvature changes at each section and its center shifts. Experimental data were obtained on the automated calculation-experimental complex SN-Computer in the deviator space of deformations A.A. Ilyushin (rigid loading) with a simultaneous combined action on the specimen of tensioncompression and torsion. Scalar and vector material properties of steel 45 are investigated. It is shown that experimental diagrams characterizing scalar and vector properties of the material have oscillatory character.

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Chen, Guang Feng, Qing Qing Huang, Lin Lin Zhai, and Qing Qing Li. "Elastic Rod Based Carpet Loop Pile Trajectory Simulation." Advanced Materials Research 680 (April 2013): 392–97. http://dx.doi.org/10.4028/www.scientific.net/amr.680.392.

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The 3D simulation of tufted carpet pile loops need to calculate the direction loop pile. By simplifying the tufted carpet yarn into elongated elastic rod, without considering the extrusion between loops piles, applying pressure at both ends of loop pile. By analyzing the elastic rod stress deformation and using Matlab simulate to determine the yarn centerline direction with the flexible line. The simulation results show that the obtained yarn centerline path is consistent with the trend of actual loop pile.

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Tang, Lu Xin, Bin Bin, and Kun Han. "The FNN Quilting Process Deformation Prediction Model." Applied Mechanics and Materials 34-35 (October 2010): 306–10. http://dx.doi.org/10.4028/www.scientific.net/amm.34-35.306.

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It is easy to have deformation that non-rigid materials is on high-speed processing, so this paper introduces the fuzzy neural networks combine with computer vision measurement technology to control this process. Based on the traditional PID control, increasing a fuzzy neural network predictor for pre-processing of trajectory compensation. Established a fuzzy neural network deformation prediction model of the single needle quilting, and simulated. Experimental and simulation results show that: error compensation which based on fuzzy neural network, have a good real-time, allow fast and accurate automated processing of quilting.

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Garanikov, V. V., and E. O. Kornilev. "RESEARCH OF THE PATTERNS OF DEFORMATION ALONG CURVILINEAR TRAJECTORIES OF CONSTANT CURVATURE WITH A CHANGING PROCESS DIRECTION." Bulletin of the Tver State Technical University. Series «Building. Electrical engineering and chemical technology», no. 3 (2020): 17–24. http://dx.doi.org/10.46573/2658-7459-2020-3-17-24.

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Abstract. An experimental study of the vector and scalar properties was carried out when changing the direction of deformation on samples made of 9X2 steel. It is shown that after the exhaustion of a certain interval of the trajectory lengths, scalar and vector properties seem to forget the change in the direction of deformation and correspond to the trajectories without changing the direction.

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Garcia-Magariño, Adelaida, Suthyvann Sor, and Angel Velazquez. "Droplet Deformation and Trajectory Without Interferences in the Incoming Airfoil Shoulder Region." AIAA Journal 58, no. 8 (August 2020): 3351–67. http://dx.doi.org/10.2514/1.j058792.

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KATO, Yoko. "1D13 Movement with large deformation and its trajectory of Halocynthia roretzi cells." Proceedings of the Bioengineering Conference Annual Meeting of BED/JSME 2013.25 (2013): 135–36. http://dx.doi.org/10.1299/jsmebio.2013.25.135.

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TSUJI, Toshio, Kazuyuki CHIGUSA, and Makoto KANEKO. "Trajectory Generation of Moving Robots Using Active Deformation of Artificial Potential Fields." Transactions of the Japan Society of Mechanical Engineers Series C 62, no. 597 (1996): 1905–11. http://dx.doi.org/10.1299/kikaic.62.1905.

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Garannikov, V. V., V. G. Zubchaninov, and N. L. Okhlopkov. "The complex deformation of metals along a plane curvilinear astroid-type trajectory." International Applied Mechanics 36, no. 7 (July 2000): 961–68. http://dx.doi.org/10.1007/bf02682306.

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Samul, A. G. "Kinematic characteristics of ultrasonic surface treatment." iPolytech Journal 26, no. 1 (April 4, 2022): 24–34. http://dx.doi.org/10.21285/1814-3520-2022-1-24-34.

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We investigate the kinematic characteristics of ultrasonic surface-plastic deformation when the oscillations are introduced in the direction tangential to the treated surface in order to assess the potential of this method for treating parts made of metals and alloys of various hardness. The kinematic parameters (trajectory, velocity, acceleration) of ultrasonic surface-plastic deformation were calculated in a rectangular coordinate system. Analytical dependencies were obtained for the trajectory length, resulting velocity, and acceleration as functions of the constituent types of motion (rotational, translational, oscillatory). The obtained equations and their graphical solutions allowed us to establish that, under ultrasonic surface-plastic deformation, the indenter moves along a complex trajectory with a variable velocity and acceleration. It is shown that the translation of ultrasonic oscillations to the indenter determines the complex nature of its movement, which differs significantly from that in the diamond burnishing method. In this case, the process parameters (velocity and acceleration) change according to a cyclic (sinusoidal) law, the periodicity of which depends on the frequency of ultrasonic oscillations and determines the final state of the treated surface. According the obtained results, the change in the input direction of ultrasonic oscillations (from normal to tangential) ensures the possibility of changing the contact condition from cyclic to constant, thereby affecting the deforming force during processing. It was found that the angle of oscillation input relative to the main velocity vector is a technological parameter significantly affecting the kinematic characteristics. An assumption is made about the possibility of using the tangential pattern of ultrasonic surfaceplastic deformation for parts made of metals and alloys of various hardness.

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Hasani, A., L. S. Toth, and Sh Mardokh Rouhani. "A New Flow Line Function for Modeling Material Trajectory and Textures in Nonequal-Channel Angular Pressing." Advances in Materials Science and Engineering 2019 (January 9, 2019): 1–6. http://dx.doi.org/10.1155/2019/5682585.

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One of the most applied severe plastic deformation processes is ECAP (equal-channel angular pressing) which is suitable to produce ultrafine-grained metallic materials with high mechanical performance. A variant of the ECAP process was proposed in 2009, which consists in reducing the diameter of the exit channel of the die; it is named the nonequal-channel angular pressing (NECAP) process. A flow line function was also proposed to describe the material flow and the deformation field during NECAP. In the present work, an improved version of that flow function is presented containing two additional parameters compared to the previously proposed function. The new parameters permit to control precisely the shapes and the positions of the flow lines. The new flow function was applied to 90° NECAP of commercially pure aluminum to characterize the deformation field and the extent of the plastic deformation zone. The crystallographic texture evolution is also simulated using the new function. Excellent agreements with experiments were obtained for both the flow line trajectories and the crystallographic texture.

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Wu, Li Ming, Si Cheng Chen, Yao Hua Deng, Fu Jian Li, and Bing Jing Li. "Research of Processing Deformation Compensation of Flexible Leather Material Based on Knowledge Management." Advanced Materials Research 912-914 (April 2014): 1681–84. http://dx.doi.org/10.4028/www.scientific.net/amr.912-914.1681.

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Leather is a common processing material with poor rigidity in shoe manufacturing, there is easy to generate tensile or compress deformation, so reducing the processing quality. Considering the reasons of leather processing deformation, there are flexible material variety, different material thickness and complicated processing path. The article discussing the various impact factors of leather cutting deformation, combined with the theory and method of processing decision knowledge acquisition, processing knowledge management, and closed-loop compensation control, to propose a deformation compensation method of leather cutting based on knowledge management. Thought the real-time processing path compensation control, to correcting the tool trajectory in process, improving the accuracy and reliability of leather cutting.

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Wang, Yaming, Jianmin Cheng, Junbao Zheng, Yingli Xiong, and Huaxiong Zhang. "Analysis of wavelet basis selection in optimal trajectory space finding for 3D non-rigid structure from motion." International Journal of Wavelets, Multiresolution and Information Processing 12, no. 03 (May 2014): 1450023. http://dx.doi.org/10.1142/s0219691314500234.

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Trajectory representation model has been proposed to describe non-rigid deformation. An optimal trajectory space finding algorithm for 3D non-rigid structure from motion (OTSF-NRSFM) based on this model also has been proposed. However, the influence of the wavelet basis selection on the OTSF-NRSFM algorithm has still not been studied. To help OTSF-NRSFM researchers select wavelet basis properly, we investigated the influences of wavelet basis selection. Two typical wavelet bases, DCT basis and WHT basis, are discussed in this paper. The spectrum properties of wavelet basis and feature point trajectory, trajectory representation results on synthetic shark data, OTSF-NRSFM reconstruction results on synthetic data and real data are analyzed. The results show that the wavelet selection has much influence on OTSF-NRSFM reconstruction results of some non-rigid feature points, which have complicated trajectory. This paper gives researchers some inspiration about wavelet basis selection in OTSF-NRSFM algorithm.

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Zhang, Yongquan, Huiming Tang, Guiying Lu, Yuansheng Wang, Changdong Li, Junrong Zhang, Pengju An, and Peiwu Shen. "Design and Testing of Inertial System for Landslide Displacement Distribution Measurement." Sensors 20, no. 24 (December 14, 2020): 7154. http://dx.doi.org/10.3390/s20247154.

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Landslide displacement monitoring plays a fundamental role in the study of landslide evolution mechanisms, forecasting, risk assessment, prevention, and control. To fill the deficiencies of traditional instrumentation for measuring landslide displacement distributed along lateral direction, a landslide displacement measurement method based on deformation-coupled pipeline trajectory measurement is proposed, and a pipeline trajectory inertial measurement instrument is developed. The developed instrument, primarily comprised of a single shaft gyro, two axis accelerometers, and an external roller encoder, is designed as an axial half strapdown-radial half platform structure combined with a mechanical gravity platform. This structure avoids the singularity of pitch angle and roll angle and can expediently calculate a pipeline trajectory with an Eulerian transformation when obtaining several basic physical variables, e.g., the axial linear velocity, pitch angle, roll angle, and azimuth angle. Additionally, the pipeline trajectory, measured at different times, possesses the ability to reflect the displacement evolution feature of landslides. The results of prototype simulation tests imply a single measurement accuracy of a 12 cm/100 m span and a singly periodic multiple (more than five times) measurement accuracy of a 3 cm/100 m span, which meets medium-precision displacement measurement requirements for a landslide. Additionally, the finished instrument has been successfully applied to the deformation monitoring of the Majiagou I# landslide, which further verifies its feasibility and offers a reference for similar landslides.

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SUVOROV, Alexandr A., and Valery B. FILATOV. "ANALYTICAL DESCRIPTION OF THE INCLINED CRACK TRAJECTORY BY THE METHOD OF NONLINEAR DEFORMATION MODEL." Urban construction and architecture 7, no. 3 (September 15, 2017): 14–18. http://dx.doi.org/10.17673/vestnik.2017.03.3.

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The article proposes an analytical solution to determine the trajectory of inclined crack with the use of nonlinear deformation model in the area of the transverse bending of a reinforced concrete beam. The use of nonlinear deformation model for the analysis of stress-strain state of the beam in the zone of the transverse bending allows to determine the coordinates of the inclined crack trajectory, the position of its vertex, and the angle of inclination to the longitudinal axis of the beam. It is then possible to move from the empirical dependences for calculating the strength of the inclined sections to precise analytical techniques. The proposed algorithms calculate and analyze the stress-strain state of reinforced concrete beams create preconditions for the implementation of the physical model of a power resistance of reinforced concrete elements under transverse bending.

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Chen, Haibo, and Xin Chen. "A Trajectory Ensemble-Compression Algorithm Based on Finite Element Method." ISPRS International Journal of Geo-Information 10, no. 5 (May 14, 2021): 334. http://dx.doi.org/10.3390/ijgi10050334.

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Trajectory compression is an efficient way of removing noise and preserving key features in location-based applications. This paper focuses on the dynamic compression of trajectory in memory, where the compression accuracy of trajectory changes dynamically with the different application scenarios. Existing methods can achieve this by adjusting the compression parameters. However, the relationship between the parameters and compression accuracy of most of these algorithms is considerably complex and varies with different trajectories, which makes it difficult to provide reasonable accuracy. We propose a novel trajectory compression algorithm that is based on the finite element method, in which the trajectory is taken as an elastomer to compress as a whole by elasticity theory, and trajectory compression can be thought of as deformation under stress. The compression accuracy can be determined by the stress size that is applied to the elastomer. When compared with the existing methods, the experimental results show that our method can provide more stable, data-independent compression accuracy under the given stress parameters, and with reasonable performance.

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Yang, Mingshun, Zimeng Yao, Yan Li, Pengyang Li, Fengkui Cui, and Lang Bai. "Study on Thickness Thinning Ratio of the Forming Parts in Single Point Incremental Forming Process." Advances in Materials Science and Engineering 2018 (June 24, 2018): 1–11. http://dx.doi.org/10.1155/2018/2927189.

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An excessive thickness-reducing ratio of the deformation zone in single point incremental forming of the metal sheet process has an important influence on the forming limit. Prediction of the deformation zone thickness is an important approach to control the thinning ratio. Taking the 1060 aluminum as the research object, the principle of thickness deformation in the single point incremental forming process was analyzed; the finite element model was established using ABAQUS. A formula with high accuracy to predict the deformation zone thickness was fitted with the simulation results, and the influences of process parameters, such as tool diameter, step down, feeding speed, sheet thickness, and forming angle, on thinning ratio were analyzed. The accuracy of the finite element simulation was verified by experiment. A method to control the thinning rate by changing the forming trajectory was proposed. The results showed that the obtained value by using the fitted formula is closer to the experimental results than that obtained by the sine theorem. The thinning rate of the deformation zone increases with the increase of tool diameter, forming angle, and sheet thickness and decreases with the increase of step down, while the feeding speed had no significant effect on the thinning ratio. The most important factor of the thinning ratio is the forming angle, and the thinning ratio can be effectively reduced by using the forming trajectory with a uniformly distributed pressing point.

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Serra, Mattia, Sebastian Streichan, Manli Chuai, Cornelis J. Weijer, and L. Mahadevan. "Dynamic morphoskeletons in development." Proceedings of the National Academy of Sciences 117, no. 21 (May 7, 2020): 11444–49. http://dx.doi.org/10.1073/pnas.1908803117.

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Morphogenetic flows in developmental biology are characterized by the coordinated motion of thousands of cells that organize into tissues, naturally raising the question of how this collective organization arises. Using only the kinematics of tissue deformation, which naturally integrates local and global mechanisms along cell paths, we identify the dynamic morphoskeletons behind morphogenesis, i.e., the evolving centerpieces of multicellular trajectory patterns. These features are model- and parameter-free, frame-invariant, and robust to measurement errors and can be computed from unfiltered cell-velocity data. We reveal the spatial attractors and repellers of the embryo by quantifying its Lagrangian deformation, information that is inaccessible to simple trajectory inspection or Eulerian methods that are local and typically frame-dependent. Computing these dynamic morphoskeletons in wild-type and mutant chick and fly embryos, we find that they capture the early footprint of known morphogenetic features, reveal new ones, and quantitatively distinguish between different phenotypes.

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Okhlopkov, N. L., S. A. Sokolov, and S. V. Cheremnykh. "Bifurcation of a cylindrical cover during complex subcritical deformation along a curvilinear trajectory." Izvestiya MGTU MAMI 7, no. 3-1 (February 10, 2013): 114–17. http://dx.doi.org/10.17816/2074-0530-68039.

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The problem of bifurcation of a thin-walled circular cylindrical cover is considered at complex subcritical deformation along a curvilinear trajectory of constant curvature in the Ilyushin deviatoric plane . There is taken into account the complex nature of loading in еру cover at the moment of stability loss.

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Shcherbakov, Vitaly, Mikhail Korytov, Elena Volf, and Irina Breus. "The Reduction of Errors of Bridge Crane Loads Movments by Means of Optimization of the Spatial Trajectory Size." Applied Mechanics and Materials 811 (November 2015): 99–103. http://dx.doi.org/10.4028/www.scientific.net/amm.811.99.

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The article dwells upon the results of study of theshape influence of size of load’s motion using the sigmoidal functions of traversingsingle obstacle on the arc with suppression of load’s oscillations to theaccuracy figure of the trajectory’s realization. The possibility of thereduction of the maximum and average error by means of the little changing of the value ofthe arc’s lateral deformation for a fixed traveling time is shown in thisarticle. The functional dependencies of the maximum and average errors oftrajectory implementation from corrected value of the maximum arc’sdisplacement of required load's trajectory in lateral side to bypass obstaclesand from increasing of corrected value of the maximum displacement of the arcare given too.

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Zhu, Dong, Yuan-Zhong Hu, Herbert S. Cheng, Takayuki Arai, and Kyugo Hamai. "A Numerical Analysis for Piston Skirts in Mixed Lubrication: Part II—Deformation Considerations." Journal of Tribology 115, no. 1 (January 1, 1993): 125–33. http://dx.doi.org/10.1115/1.2920965.

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This paper presents a mathematical model for piston skirts in mixed lubrication. It takes into account the effects of surface waviness, roughness, piston skirt surface profile, bulk elastic deformation and thermal distortion of both piston skirts and cylinder bore on piston motion, lubrication and friction. The corresponding computer program developed can be used to calculate the entire piston trajectory and the hydrodynamic and contact friction forces as functions of crank angle under engine running conditions. Complete distributions of the oil film thickness and elastic deformation as well as the hydrodynamic and contact pressures can also be given at any crank angle if needed. This paper is the second part of a series of two papers. The first part (Basic Modeling), presented earlier by Zhu et al. (1991), gave the basic formulation and some preliminary results without bulk deformation considerations. In the present part, the three-dimensional finite element method is used to calculate so-called influence coefficient matrices. These matrices are repeatedly used to compute bulk elastic deformations of piston skirts. Results for 12 different cases are presented, and discussions are given focusing on the influences of elastic and thermal deformations on piston motion, lubrication and friction. An attempt to compare the calculated friction with experimental data is made, and agreement appears good for the two available cases. The computer program presented should be a useful tool for piston design and development.

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Ren, Bo, Tianjiao Li, and Xiang Li. "Research on Dynamic Inertial Estimation Technology for Deck Deformation of Large Ships." Sensors 19, no. 19 (September 25, 2019): 4167. http://dx.doi.org/10.3390/s19194167.

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Many kinds of weapon systems and launching equipment on the deck of large ships are easily affected by deck deformation. In order to ensure the accuracy of weapon systems and the safety of taking off and landing of carrier aircraft, a dynamic estimation method combining the main inertial navigation systems (INS) and the sub-inertial navigation systems (SINS) is designed to estimate the curvature and torsion of any trajectory on the deck. Our contributions start from the fact that the area of concern extends from the fixed points to any trajectory on the deck. The dynamic filter algorithm of wavelet combined with Kalman filter is used to process the acquired data. The wavelet method is used to remove the outliers in the acquired data, and the Kalman filter effectively reduces the influence of white noise, so that the estimation accuracy is guaranteed. The simulation results clearly show that the deck deformation of large ships can be obtained accurately in real-time over the observed area which proved that this dynamic inertial measurement method is feasible in practical engineering application.

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Severov, A. A., L. I. Gracheva, V. N. Koloskova, and Vad V. Vengzhen. "Thermal deformation of a polymer heat-shielding material on the trajectory of descent." Strength of Materials 24, no. 4 (April 1992): 327–32. http://dx.doi.org/10.1007/bf00777353.

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Lindsay, R. W., and H. L. Stern. "The RADARSAT Geophysical Processor System: Quality of Sea Ice Trajectory and Deformation Estimates." Journal of Atmospheric and Oceanic Technology 20, no. 9 (September 2003): 1333–47. http://dx.doi.org/10.1175/1520-0426(2003)020<1333:trgpsq>2.0.co;2.

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Rastgoftar, Hossein, and Ilya V. Kolmanovsky. "A spatio-temporal reference trajectory planner approach to collision-free continuum deformation coordination." Automatica 142 (August 2022): 110255. http://dx.doi.org/10.1016/j.automatica.2022.110255.

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Zhu, Dong, Herbert S. Cheng, Takayuki Arai, and Kyugo Hamai. "A Numerical Analysis for Piston Skirts in Mixed Lubrication—Part I: Basic Modeling." Journal of Tribology 114, no. 3 (July 1, 1992): 553–62. http://dx.doi.org/10.1115/1.2920917.

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This paper presents a mathematical model for piston skirts in mixed lubrication. It takes into account the effects of surface waviness, roughness, piston skirt surface profile, bulk elastic deformation and thermal distortion of both piston skirts and cylinder bore on piston motion, lubrication and friction. The corresponding computer program developed can be used to calculate the entire piston trajectory and the hydrodynamic and contact friction forces as functions of crack angle under engine running conditions. This paper is the first part of a series of two papers. It gives basic information and some preliminary results. The second part will include the major results and discussions, focused on the influences of elastic and thermal deformations.

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Uehara, Takuya. "An Atomistic Study on the Slip Deformation Mechanism of Crystalline Materials Using a Weak-Plane Model." Applied Mechanics and Materials 197 (September 2012): 321–26. http://dx.doi.org/10.4028/www.scientific.net/amm.197.321.

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Molecular dynamics simulations were carried out to investigate the plastic deformation mechanism of fcc crystalline materials using the conventional Lennard-Jones potential. An fcc structure with square cross-section was prepared, and a tensile load was applied in the longitudinal direction. A weak potential was assigned to a specific (111) plane to induce a slip on the specified plane. Accordingly, a slip was initiated in the weak plane following an elastic deformation. The step-by-step motion of the atoms on the slip plane was studied, and a detailed trajectory is presented. The slip then expanded to other planes, and plastic deformation progressed in the whole model. The weak plane was also set as (110) or (100) plane, where different deformation modes were observed: not only slip but also gradual distortion or brittle fracture occurred.

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Journal articles on the topic 'Trajectory deformation'

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