Academic literature on the topic 'Deformation trajectory'
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Journal articles on the topic "Deformation trajectory"
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Matviychuk, Viktor, Volodymyr Mykhalevych, and Andrii Shtuts. "ANALYSIS OF STRESS-STRAIN STATE (SSS) OF BILLET MATERIAL IN THE COURSE OF SETTING BY RESOURCE-SAVING METHOD OF ROLL STAMPING." Vibrations in engineering and technology, no. 1 (108) (May 1, 2023): 63–72. http://dx.doi.org/10.37128/2306-8744-2023-1-7.
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The processes of planting blanks by the rolling stamping method allow for the efficient production of a wide range of high-quality products, but the possibility of material destruction during deformation prevents the expansion of their technological capabilities. Further development of the processes is possible through the development of new technological schemes based on the analysis of deformation kinematics and the appointment of favorable technological parameters, taking into account their influence on the stress-strain state and deformability of the material of the workpieces. In order to widely use the method of assessing the deformability of workpieces, a reliable technique is needed, which provides for the presence of a mathematical model of the trajectory of deformation of material particles in the coordinates "stress state indicator - accumulated plastic deformation before failure." The work uses an approach to finding an analytical representation of the deformation trajectory based on the construction of a differential equation between the components of plastic deformation increments, followed by the solution of this equation and the identification of its parameters based on experimental data. According to the results of the research, the deformation trajectories of the material particles of the peripheral surface of the flange when planting by rolling stamping method were schematically constructed in the coordinates "intensity of deformations - stress state indicator". Based on the built model, damage accumulation can be simulated by changing the values of the model parameters for different materials and deformation paths. An analytical representation of the deformation trajectory in a parametric form was obtained. The advantages of representing the deformation trajectory in the form of parametric equations are the convenience of analyzing these trajectories. The advantage of the model of the trajectory of deformation of material particles in the coordinates "stress state indicator - plastic strain accumulated before failure" is the absence of a material constant in the analytical expression for the stress state, and the consequence is additional convenience of analyzing ratios and selecting the value of the material constant based on experimental data. Key words: rolling stamping, flange landing, stress-strain state, mathematical model of the deformation trajectory.
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Matviychuk, Viktor, Volodymyr Mykhalevych, and Andrii Shtuts. "ANALYSIS OF THE STATE OF STRESS AND DEFORMATION OF THE MATERIAL OF THE BILLET WHEN PLANTING BY THE RESOURCE-SAVING METHOD OF STAMPING BY ROLLING." ENGINEERING, ENERGY, TRANSPORT AIC, no. 1(120) (May 1, 2023): 76–85. http://dx.doi.org/10.37128/2520-6168-2023-1-9.
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The processes of planting blanks by the rolling stamping method allow for the efficient production of a wide range of high-quality products, but the possibility of material destruction during deformation prevents the expansion of their technological capabilities. Further development of the processes is possible through the development of new technological schemes based on the analysis of deformation kinematics and the appointment of favorable technological parameters, taking into account their influence on the stress-strain state and deformability of the material of the workpieces. In order to widely use the method of assessing the deformability of workpieces, a reliable technique is needed, which provides for the presence of a mathematical model of the trajectory of deformation of material particles in the coordinates "stress state indicator - accumulated plastic deformation before failure." The work uses an approach to finding an analytical representation of the deformation trajectory based on the construction of a differential equation between the components of plastic deformation increments, followed by the solution of this equation and the identification of its parameters based on experimental data. According to the results of the research, the deformation trajectories of the material particles of the peripheral surface of the flange when planting by rolling stamping method were schematically constructed in the coordinates "intensity of deformations - stress state indicator". Based on the built model, damage accumulation can be simulated by changing the values of the model parameters for different materials and deformation paths. An analytical representation of the deformation trajectory in a parametric form was obtained. The advantages of representing the deformation trajectory in the form of parametric equations are the convenience of analyzing these trajectories. The advantage of the model of the trajectory of deformation of material particles in the coordinates "stress state indicator - plastic strain accumulated before failure" is the absence of a material constant in the analytical expression for the stress state, and the consequence is additional convenience of analyzing ratios and selecting the value of the material constant based on experimental data.
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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 (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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Zubchaninov, V. G., V. I. Gultyaev та A. S. Dvuzhilov. "ИССЛЕДОВАНИЕ ЛАТУНИ Л63 ПО ГЛАДКОЙ КРИВОЛИНЕЙНОЙ ТРАЕКТОРИИ ТИПА “ВЕЕР СМЕЩЕННЫХ ОКРУЖНОСТЕЙ”". Вестник Чувашского государственного педагогического университета им. И.Я. Яковлева. Серия: Механика предельного состояния, № 1(55) (6 червня 2023): 26–32. http://dx.doi.org/10.37972/chgpu.2023.55.1.004.
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The article presents the results of an experimental study of deformation of a thinwalled tubular sample along a smooth curvilinear trajectory of deformation of different curvature, in which each section of the trajectory changes the value of curvature and moves it center. The experiments were carried out on an automated calculation and experimental complex SN-EVM in the deviatoric space deformations A.A. Ilyushin (hard loading) with simultaneous combined action on a thin-walled tubular tensile-compression sample and twists. Scalar and vector material properties were subject to research brass L63. It was revealed that the resulting diagrams that characterize scalar and vector material properties are oscillatory. В статье описаны результаты эксперимента деформирования по гладкой криволинейной траектории трубчатого тонкостенного образца. На каждом участке траектории менялось значение кривизны и одновременно перемещался ее центр. Экспериментальные исследования проводились в девиаторном пространстве деформаций А.А. Ильюшина на экспериментальном автоматизированном комплексе СН-ЭВМ,с учетом одновременного, комбинированного действия на трубчатый образец кручения и растяжения-сжатия .Исследованию подлежали скалярные и векторные свойства материала латунь Л63. Выявлено, что полученные диаграммы, которые показывают векторные и скалярные свойства материала имеют колебательный характер.
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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 (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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Piras, Paolo, Valerio Varano, Maxime Louis, et al. "Transporting Deformations of Face Emotions in the Shape Spaces: A Comparison of Different Approaches." Journal of Mathematical Imaging and Vision 63, no. 7 (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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Wang, Hao, Junwu Hong, Dehong Meng, Wei Li, and Hao Yue. "Numerical simulation of the effect of elastic deformation on the fairing separation process." Journal of Physics: Conference Series 2599, no. 1 (2023): 012007. http://dx.doi.org/10.1088/1742-6596/2599/1/012007.
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Abstract In view of the potential impact of structural deformation on the separation safety of elastic fairing at low altitude and high speed, the aerodynamic/deformation/motion coupling analysis method is established. The numerical simulation of the separation process of the fairing considering elastic deformation after disengaging is carried out. The motion characteristics and structural response characteristics of the elastic fairing in the separation process are obtained. Moreover, the impact of elastic deformation on the attitude and trajectory of the fairing is studied. The results indicate that the elastic deformation has an impact on the attitude and trajectory of the fairing after hinge decoupling. However, for the calculation conditions in this paper, elastic deformation has no subversive effect on the separation safety.
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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 (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.
Dissertations / Theses on the topic "Deformation trajectory"
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Sobrero, Franco Sebastian. "Logarithmic and Exponential Transients in GNSS Trajectory Models as Indicators of Dominant Processes in Post-Seismic Deformation." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu153174766741719.
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Delsart, Vivien. "Navigation autonome en environnement dynamique : Une approche par déformation de trajectoire." Grenoble, 2010. https://theses.hal.science/tel-00592259.
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Cette thèse aborde le problème de navigation d'un système robotique en environnement dynamique et incertain. Plus particulièrement, elle s'intéresse à la détermination du mouvement pour un robot, permettant de rejoindre une position donnée tout en assurant sa propre sécurité et celle des différents agents qui l'entourent. Entre approches délibératives - consistant à déterminer à priori un mouvement complet vers le but - et approches réactives - calculant au cours de la navigation un mouvement à suivre à chaque instant - ont émergé les approches de déformation de mouvement, combinant à la fois une planification de mouvement globale avec un évitement d'obstacles réactif local. Leur principe est simple : un chemin complet jusqu'au but est calculé à priori et fourni au système robotique. Au cours de l'exécution, la partie du mouvement restant être exécutée est déformée continuellement en réponse aux informations sur l'environnement récupérées par les capteurs. Le système peut ainsi modifier son parcours en fonction du déplacement d'obstacles ou de l'imprécision et l'incomplétude de sa connaissance de l'environnement. La plupart des approches de déformations existantes se contentaient de modifier uniquement le chemin géométrique suivi par le robot. Nous proposons alors d'étendre les travaux précédents à une déformation de trajectoire modifiant le mouvement suivi à la fois dans l'espace et dans le temps. Pour ce faire, nous proposons de raisonner sur le futur en utilisant une estimation du comportement futur des obstacles mobiles. En éloignant la trajectoire suivie par le robot du modèle prévisionnel du comportement des obstacles, il est ainsi possible d'anticiper leur mouvement. La trajectoire déformée étant modifiée arbitrairement dans l'espace et dans le temps, l'une des principales difficultés de cette approche consiste à maintenir le respect des contraintes sur le mouvement du robot le long de cette trajectoire et sa convergence vers le but. Une approche de génération de trajectoire avec contrainte sur le temps final a été développée dans ce but. En discrétisant la trajectoire déformée en une séquence d'états-temps successifs, le générateur de trajectoires permet de vérifier si un mouvement faisable existe entre chaque triplé d'états-temps de la trajectoire déformée, et dans le cas contraire de la modifier localement afin de restaurer sa faisabilité. Les approches de déformation et de génération de trajectoire proposées ont été illustrées en simulation puis quelques expérimentations ont été réalisées sur une chaise roulante automatisée<br>This thesis presents a navigation method in uncertain and dynamic en- vironment. More precisely, it consists in determining the motion of a robot from an initial position to a goal one, while preventing the robot to collide with the other agents evolving in its environment. Between deliberative approaches - consisting in determining a priori a complete motion to the goal - and reactive approaches - computing a new motion to execute at each time step during the robot navigation - have arisen the motion deformation approaches, combining a motion planning method with a reactive obstacle avoidance process. Their principle is simple : A priori complete motion is planned up to the goal and provided to the robotic system. During the course of the execution, the remaining part of the motion to execute is continually deformed in response to information provided by the sensors. The robot is consequently able to adapt its motion to the behaviour of the moving obstacles or to the incompleteness of its environment knowledge. Most of the existing motion deformation methods only deform the geometric path followed by the robot. We propose thus to extend the previous approaches to a trajectory deformation approach that modify the followed motion either in space or time. To do it, trajectory deformation reason on an estimation of the future motion of the obstacles. By preventing the trajectory followed by the robot to collide with a forecast model of the future motion of the obstacles, the robotic system may anticipate their motion. As the deformed trajectory is arbitrarily modified in time and space, one of the major difficulties of the approach is to keep the motion constraints of the robot satisfied along the trajectory. In that aim, a trajectory generation approach with a final time constraint has thus been developed. By discretizing the deformed trajectory in a sequence of state-times, the trajectory generation process allows to check if a feasible motion exists between each triplet of successive state-times, and should the opposite case occur they are modified to restore the connectivity of the deformed trajectory. The trajectory deformation and trajectory generation with final time constraints have been illustrated by simulation results, and a few experiments have been proceeded on an automated wheelchair
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Mikaelian, David. "Etude de la dynamique et de la morphologie de bulles confinées et non confinées, et de leur transfert de matière vers le liquide environnant." Doctoral thesis, Universite Libre de Bruxelles, 2014. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209213.
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Cette thèse porte sur l'étude de la dynamique et de la morphologie de bulles non confinées dans des colonnes à bulles et de bulles confinées dans des microcanaux, ainsi que sur l'étude du transfert de matière entre une bulle sphérique confinée dans un microcanal et le liquide environnant. <p><p>Un dispositif expérimental d'imagerie et une méthode de posttraitement des images brutes ont été développés afin d'analyser la dynamique et la morphologie de bulles non confinées ayant une trajectoire non rectiligne de leur centre de masse en évitant les effets de perspectives et en déterminant un seuil pour la binarisation des images brutes sur base d'un critère bien défini. Ce dispositif expérimental et cette méthode de posttraitement des images brutes ont permis de générer des données relatives à la dynamique et la morphologie de bulles ellipsoïdales isolées et non confinées, pour des nombres d'Eötvös (Eo) et de Morton (Mo) de ces bulles tels que 0.8 < Eo < 8 et 10 <SUP>-11</SUP> < Mo < 10 <SUP>-7</SUP>. L'analyse de ces données a permis de cartographier la nature de la trajectoire d'une bulle et la présence d'une éventuelle oscillation de son interface en fonction de ses nombres d'Eötvös et de Morton. Les bulles ayant une trajectoire hélicoïdale sans oscillation de leur interface ont été sélectionnées afin de proposer des corrélations pour calculer l'amplitude et la fréquence de leur trajectoire en fonction de leurs nombres d'Eötvös et de Morton. Concernant les bulles ayant une trajectoire en zigzag ou hélicoïdale sans oscillation de leur interface, l'analyse des données a permis de montrer l'alignement entre le vecteur vitesse de leur centre de masse et leur petit axe. Les rayons de courbure de l'avant et l'arrière de l'interface de ces bulles ont été évalués. Pour les bulles ayant une trajectoire en zigzag, une corrélation a été établie pour calculer le rapport des rayons de courbure à l'avant et à l'arrière de leur interface en fonction de leurs nombres d'Eötvös et de Morton. Une pulsation dans la composante verticale du mouvement du centre de masse d'une bulle a été observée dans le cas d'une trajectoire en zigzag de la bulle et ce à une fréquence égale au double de celle de sa trajectoire. Une telle pulsation n'a pas pu être identifiée dans le cas d'une trajectoire hélicoïdale d'une bulle. <p><p>Concernant l'analyse de la dynamique de bulles sphériques confinées dans des microcanaux de sections carrée et circulaire, ainsi que du transfert de matière entre ces bulles et le liquide environnant, une méthode numérique a été développée dans laquelle deux conditons aux limites sont considérées sur l'interface liquide-gaz: une condition de contrainte tangentielle nulle et une condition de non glissement. Les résultats obtenus avec cette méthode ont permis de caractériser les champs de vitesse et de concentration autour des bulles considérées, et de montrer leurs interactions. Grâce à ces résultats, des corrélations ont été établies, dans ces microcanaux et pour ces deux conditions aux limites, pour calculer la vitesse des bulles et pour caractériser le transfert de matière entre ces bulles et le liquide en fonction des paramètres définissant le système. Sur base de ces corrélations et de bilans de matière et de quantité de mouvement, un modèle pour la dissolution de bulles le long de microcanaux de sections carrée et circulaire a été proposé, pour le régime bubbly flow, et comparé avec des données expérimentales disponibles dans la littérature. Ce modèle permet de prédire, pour une bulle se mouvant le long d'un microcanal de section carrée ou circulaire, les évolutions des pressions dans le liquide et le gaz, de son diamètre, de sa vitesse, de la concentration du gaz dissous dans le liquide, de la distance de séparation entre cette bulle et la bulle qui la suit et du coefficient de transfert de matière entre cette bulle et le liquide environnant.<p><p><br>Doctorat en Sciences de l'ingénieur<br>info:eu-repo/semantics/nonPublished
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SEO, TAE-IL. "Integration des effets de deformation d'outil en generation de trajectoire d'usinage." Nantes, 1998. http://www.theses.fr/1998NANT2062.
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Notre etude porte sur l'elaboration d'une methode de generation de trajectoires d'usinage en fraisage qui integre les effets de deformation d'outils. A partir d'une base de donnees outil-matiere, nous determinons les parametres du modele de calcul d'efforts de coupe. L'algorithme de compensation propose permet l'obtention de la trajectoire souhaitee sans reduction de la productivite (conservation des memes conditions de coupe). Il s'appuie sur une modelisation de l'outil de type resistance des materiaux. La notion de diametre equivalent est introduite pour prendre en compte la morphologie de l'outil. La compensation a apporter est calculee, de maniere iterative, par la methode du miroir. Des applications, en simulation et experimentales, sont presentees. Nous nous attachons ensuite aux problemes lies au choix de la reference de compensation en prenant comme critere le tolerancement de la piece. Nous simulons la surface obtenue par une methode integrant la notion de point de contact outil-piece et nous proposons une trajectoire compensee qui assure le respect de la tolerance. Dans le cas ou cette compensation n'est pas possible plusieurs solutions sont proposees : optimisation des conditions de coupe, optimisation des strategies d'usinage. Finalement nous presentons des applications de notre methode. Une comparaison experimentale-simulation est effectuee sur differentes formes de pieces et un cas industriel est traite.
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Bonnefis, Paul. "Etude des instabilités de sillage, de forme et de trajectoire de bulles par une approche de stabilité linéaire globale." Thesis, Toulouse, INPT, 2019. http://www.theses.fr/2019INPT0070/document.
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Ce travail porte sur le couplage des déformations d'une bulle avec son sillage et sa trajectoire dans plusieurs configurations. Un formalisme de type eulérien-lagrangien permet d'écrire le problème sur un domaine mouvant faiblement déformé par rapport à la configuration de référence. Grâce à cette approche, il est possible d'étudier dans un cadre linéaire le couplage entre les déformations d'une bulle et les effets hydrodynamiques. En appliquant ce formalisme, on peut dans un premier temps calculer l'écoulement de base autour de la bulle et sa géométrie d'équilibre, et dans un second temps développer une approche de stabilité globale prédisant les seuils d'instabilité et les propriétés des modes d'oscillation. Afin de développer cette méthode, des résultats sur les oscillations linéaires de bulles et de gouttes dans un fluide au repos et sans influence de la gravité sont tout d'abord présentés et comparés à des résultats théoriques existants. Puis, le principe du formalisme eulérien-lagrangien est illustré en prenant pour problème modèle l'équation de la chaleur formulée sur un domaine arbitrairement déformé. Ce principe est ensuite appliqué aux équations de Navier-Stokes, aboutissant à une version linéarisée autour d'un domaine de référence incluant de manière complète les couplages entre déformations de la géométrie et perturbations de l'écoulement. On met en oeuvre sur le système obtenu une méthode itérative de Newton donnant accès à l'état de base, c'est-à-dire à l'écoulement stationnaire autour de la bulle et à sa forme d'équilibre. Ce même système permet par la suite d'effectuer une analyse de stabilité globale de l'écoulement autour d'une bulle qui se déforme. L'algorithme développé est d'abord appliqué au cas d'une bulle piégée dans un écoulement d'étirement, permettant de décrire des formes d'équilibre dans des régimes stables et instables. Le cas de la bulle en ascension dans un fluide pur est ensuite abordé. Une étude paramétrique est conduite, couvrant une vaste gamme de liquides allant de l'eau pure à des huiles de silicone très visqueuses. Les états de base calculés par la méthode de Newton ainsi que les seuils d'instabilité des sillages sont en bon accord avec les résultats expérimentaux. Dans les cas des liquides très peu visqueux, notre approche décrit de manière plus précise les effets visqueux dans les couches limites et donne des résultats plus satisfaisants que les approches numériques existantes. Elle confirme par ailleurs que la déformation de la bulle joue un rôle mineur dans ces gammes de paramètres. Pour les liquides plus visqueux en revanche, on observe un couplage plus fort entre déformation et sillage<br>This works deals with the coupling between time-dependent deformation, wake dynamics and path characteristics of a gas bubble in different configurations. An Eulerian-Lagrangian formalism is sought to formulate this problem in a moving domain having a small deformation compared to the reference configuration. This approach allows us to study the linear coupling between bubble deformations and hydrodynamic effects. This formalism makes it possible to first compute the base flow around a bubble and the corresponding steady shape, then to develop a global stability approach aimed at predicting the threshold of path instability and the properties of bubble oscillation modes. To develop this method, we first compute the linear oscillations of bubbles and drops in a quiescent fluid without gravity and compare them to existing theory. Then, the premise of the Eulerian-Lagrangian formalism is illustrated using a model equation, namely the heat equation written in an arbitrarily deformed domain. The same formalism is applied to the NavierStokes equations, yielding a linearized version of these equations in the neighbourhood of a reference domain, including the two-way coupling between shape deformations and perturbations of the base flow. With this system of equations at hand, we implement a Newton method that provides the steady state, i.e. the base flow around the bubble and its geometry. The same system allows us to carry out a global stability analysis of the flow past a deformable bubble. We first consider the situation where the bubble is trapped in a straining flow, for which we compute stable and unstable equilibrium shapes. We finally tackle the case of a buoyancy-driven bubble rising in a pure liquid. A parametric study is carried out over a wide range of liquids, from pure water to high-viscosity silicon oils. Steady states computed with the Newton method and instability thresholds are found to be in good agreement with experimental observations. For low-viscosity fluids, our approach captures the viscous effects that take place in the boundary layer better than existing computational approaches, yielding predictions for the onset of path instability in better agreemnt with observations. Furthermore, it confirms that time-dependent bubble deformations play a minor part for such liquids. In contrast, a stronger coupling between shape and path instabilities is observed in high-viscosity fluids
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Wang, Sheng-Yi, and 王盛儀. "Digital Image Correlation of Two-Dimensional Trajectory and Deformation Measurement and Applied to Construct 3D Surface." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/8gp2vs.
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碩士<br>國立臺灣大學<br>機械工程學研究所<br>106<br>This thesis start from verifying 2D Digital Image Correlation (DIC) ability then expand the topic to 3D measuring errors, and finally build a 3D surface constructing system by using single camera and automatic devices.
2D DIC trajectory measurement ability can be proven by comparing to 1D LASER displacement meter result, and have successfully matched by measuring XXY precision stage origin motion trajectory and displacement. The stage operating system had defect of overshooting, and have been fixed by applying a protecting logic circuit which will block the motor input for state of limit. Also, the system is changed into MATLAB environment for compatibility and has improved the degree of freedoms for angle displacement, direction and speed. The stage is found having better trajectory result compared with the shape of input command while operating with lower speed.
Measurement of a three-point-forced acrylic circular plate is used to verify the full-field displacement and deformation ability of 2D DIC. The result of displacement and deformation measured by 2D DIC system are similar to the displacement and deformation simulations computed by COMSOL.
This thesis presents a relationship between 2D and 3D measurement error derived by geometry, and gives a procedure to make sub-pixel standard image which verifies the 2D DIC method with an accuracy of 0.02 pixel. 3D measurement error can be predict by applying coordinate values of point in 3D space and error on 2D plane and verified by a test measuring feature point in different positions.
At last, the thesis build a 3D surface measuring system by single camera, a single axis robot and precision stage, which have the possibility to capture photos for different view angle. The system ability is verified from measuring checker board plane, and successfully built 3D surface of an unequal diameter PVC pipe and a Beethoven plaster statue.
Book chapters on the topic "Deformation trajectory"
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Ghafouri, M., and F. Lestienne. "Gesture Orientation and Trajectory Deformation in Three Dimensional Space." In Progress in Gestural Interaction. Springer London, 1997. http://dx.doi.org/10.1007/978-1-4471-0943-3_21.
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Lamiraux, Florent, and Olivier Lefebvre. "Sensor-based Trajectory Deformation: Application to Reactive Navigation of Nonholonomic Robots." In Visual Servoing via Advanced Numerical Methods. Springer London, 2010. http://dx.doi.org/10.1007/978-1-84996-089-2_17.
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Chen, Huiqun, and Fenpin Jin. "A Novel Approach for Surface Topography Simulation Considering the Elastic-Plastic Deformation of a Material During a High-precision Grinding Process." In Proceeding of 2021 International Conference on Wireless Communications, Networking and Applications. Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-2456-9_118.
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AbstractA novel simulation approach for 3D surface topography that considers the elastic-plastic deformation of workpiece material during a high-precision grinding process is presented in this paper. First, according to the kinematics analysis for the abrasive grain during the grinding process, the motion trajectory of the abrasive grain can be calculated. Second, the kinematic interaction between the workpiece and the abrasive grains can be established, which integrates the elastic-plastic deformation effect on the workpiece material with the topography, the simulation results are more realistic, and the simulation precision is much higher. Finally, based on an improved surface applied to the grinding wheel, the surface topography of the workpiece is formed by continuously iterating overall motion trajectories from all active abrasive-grains in the process of high-precision grinding. Both the surface topography and the simulated roughness value of this work are found to agree well with those obtained in the experiment. Based on the novel simulation method in this paper, a brand-new approach to predict the quality of the grinding surface by providing machining parameters, selecting effective machining parameters, and further optimizing parameters for the actual plane grinding process, is provided.
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Gong, Lanxin, Changhong Peng, and Zhenze Zhang. "Study on Coupling Effect and Dynamic Behavior of Double Bubbles Rising Process." In Springer Proceedings in Physics. Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-99-1023-6_82.
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AbstractGas-liquid two-phase flow widely exists in nuclear energy engineering, in which bubble movement and deformation are critical problems. Because the activity of bubbles in the fluid is a very complex physical process, and the movement process is a flow field-bubble coupling process, which has strong nonlinearity and unsteady, the relevant research is usually based on experiments and simulation.We built a medium-sized experimental device to generate double bubbles with different sizes and characteristic numbers and recorded the motion trajectory with a high-speed camera. We developed and improved the image processing method to obtain high-quality bubble motion information and realized a good capture of bubble shape and rotation.The experimental results show that in the two bubbles rising successively, the trailing bubble is affected by the trailing field of the leading bubble, and the bubble velocity, relative distance, deformation rate, and other parameters change accordingly. In addition, through simulation, we get the interaction mechanism of the bubbles under experimental conditions. The results show that the coupling leads to flow field velocity and pressure changes, which explains the experimental results. The research results are helpful for a thorough understanding of the law of bubble movement and provide empirical data support for developing a thermal-hydraulic model.
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Chen, Jianquan, Yi Zhaung, Ruichuang Chen, Hongde Ma, and Zhaoxiao Wu. "Degree and Classification of Winding Deformation Faults Based on Least-Squares Fitting of Lissajous Trajectory Coefficient Recognition." In Lecture Notes in Electrical Engineering. Springer Nature Singapore, 2025. https://doi.org/10.1007/978-981-97-4620-0_20.
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Klare, Stefan, Volodymyr Shramenko, Lars Klingel, Bernd Lüdemann-Ravit, and Alexander Verl. "Towards Automotive Manufacturing Efficiency: Enhanced Virtual Commissioning Simulation for Dynamic Sheet Metal Handling Optimization." In ARENA2036. Springer Nature Switzerland, 2025. https://doi.org/10.1007/978-3-031-88831-1_6.
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Abstract Automated sheet metal handling in the automotive industry using robot manipulators is a standard in modern production. However, the desire of automotive companies to speed up the production process on the assembly line and at the same time to reduce expensive hardware components poses new challenges for robotics. Excessively rapid movement of flexible parts or sheet metal can either lead to its plastic deformation or increase the decay time of the vibrations to such an extent that it is necessary to wait before the part can be further processed, for example by welding. The traditional approach to solving these problems is to add fixing points for the part and/or to allow for waiting times at the end of the robot movement to ensure that the sheet metal vibration subsides. This means that more effort than necessary has to be put into the hardware setup or a poor cycle time has to be accepted. In our work, we propose to improve virtual commissioning systems by conducting a deeper analysis of the dynamics of sheet metal parts during its movement by the robot. To achieve this, a three-step optimization strategy is proposed. The first step is a structural transient analysis of the thin metal part under disturbances that arise during its movements. The second step is the creation of a substitute model, which is trained on the basis of the data obtained in the first phase and considerably reduces the computing time required compared to the time needed for a finite element method (FEM) simulation. Subsequently, this is used to optimize robotic handling efficiency by optimizing the robot trajectory. By addressing the challenges posed by sheet metal dynamics, enhanced process control, reduced cycle times, and ultimately, improved manufacturing outcomes are anticipated.
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"deformation trajectory." In Dictionary Geotechnical Engineering/Wörterbuch GeoTechnik. Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-41714-6_40849.
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"Affine Trajectory Deformation for Redundant Manipulators." In Robotics. The MIT Press, 2013. http://dx.doi.org/10.7551/mitpress/9816.003.0047.
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Liu, Chao-Chung, Jun-Chi Liu, and Chao-Shu Liu. "Investigation of a 7-Axis Suspended Robotic Arm for Automated Spraying System." In Advances in Transdisciplinary Engineering. IOS Press, 2024. https://doi.org/10.3233/atde241236.
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This study successfully develops a 7-axis suspended robotic arm for an automated spraying system, considering factors such as flexible operation modes, spray area dimensions, workpiece geometry, and the degrees of freedom required for effective operation. By using SolidWorks software for verification, the endpoints of the robotic arm can reach all positions within the workspace. The design and fabrication of the arm are completed according to specifications for structural strength, load capacity, rated torque output, and rotational speed. Kinematic analyses, both forward and inverse, are applied to determine the posture and position of the 7-axis robotic arm, facilitating the planning and design of the spraying trajectory. The control system architecture utilizes a multi-axis servo control board, integrated with a manifold deformation control method for trajectory tracking. Simulations and experiments are conducted to use a car shell workpiece provided by the manufacturer. The results from the simulations of MATLAB analyses show that the maximum tracking error is less than 0.4 mm. In experiments with the robotic arm, the maximum error is less than 0.7 mm. The results of the simulation and experiment are quite close, indicating that the deformation control method effectively operates the posture and movement of the 7-axis suspended robotic arm. Therefore, the 7-axis suspended robotic arm developed in this study will be effectively utilized in the production line of the automated spraying system.
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He Manru, Chen Hong-En, Xie Shejuan, Chen Zhenmao, and Lin Junming. "Nondestructive Evaluation of Plastic Deformation in Reduced Activation Ferritic/Martensitic Steels for Structure of Fusion Reactors." In Studies in Applied Electromagnetics and Mechanics. IOS Press, 2016. https://doi.org/10.3233/978-1-61499-639-2-171.
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Reduced Activation Ferritic/Martensitic (RAFM) steel is considered to be a candidate structural material for future Tokamak fusion nuclear reactors. The plastic deformation may occur during the operation of the reactor for reason of unexpected loads. Therefore, a reliable non-destructive evaluation (NDE) of RAFM steel is needed. In this study, magnetic NDE methods such as magnetic Barkhausen noise (MBN), magnetic incremental permeability (MIP) and magnetic flux leakage (MFL) method have been applied to evaluate the residual plastic strains in RAFM steel to ensure the structural integrity after an unexpected giant loading process. The study shows that the MBN signals and the amplitude of the high harmonic components of the MFL signals decrease regularly with the increasing residual strain. The shape of MIP butterfly trajectory also changes evidently in range of small plastic deformation. The experimental results reveal that the MFL method is the most suitable way in the three magnetic NDE methods for measurement of plastic strain in the RAFM steels.
Conference papers on the topic "Deformation trajectory"
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Liu, Jiangpin, Tong Yang, Wangtao Lu, Yue Wang, and Rong Xiong. "Online Trajectory Deformation and Tracking for Self-entanglement-free Differential-Driven Robots." In 2024 IEEE International Conference on Robotics and Automation (ICRA). IEEE, 2024. http://dx.doi.org/10.1109/icra57147.2024.10611150.
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Kurniawati, Hanna, and Thierry Fraichard. "From path to trajectory deformation." In 2007 IEEE/RSJ International Conference on Intelligent Robots and Systems. IEEE, 2007. http://dx.doi.org/10.1109/iros.2007.4399235.
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Esser, Felix, José Angel Moraga, Lasse Klingbeil, and Heiner Kuhlmann. "Accuracy improvement of mobile laser scanning point clouds using graph-based trajectory optimization." In 5th Joint International Symposium on Deformation Monitoring. Editorial de la Universitat Politècnica de València, 2022. http://dx.doi.org/10.4995/jisdm2022.2022.13728.
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The detection of deformations on man-made structures such as bridges and dams are an essential task in engineering geodesy. The classical method uncovering deformations is based on geodetic networks using measurements from total stations or GNSS receivers. Another new approach is the determination of deformations based on terrestrial laser scans leading to large-scale deformation results by point cloud comparisons. In the field of geodetic engineering, mobile laser scanning systems are increasingly used for high-resolution point cloud generation in short measurement times, which leads to the idea to use these for deformation analysis. A crucial part of this measurement strategy is the estimation of the trajectory (position and orientation) of the scanner, which allows a consistent registration of the single scan lines in a global coordinate system (georeferencing). The largest limitation to the accuracy of the resulting point cloud is the accuracy of the estimated trajectory. In most applications, the estimation of position and orientation are based on the fusion of GNSS (Global Navigation Satellite System) and IMU (Inertial Measurement Unit) measurements. Systematic errors, as they often appear in GNSS measurements, are directly transferred to the georeferenced point cloud and therefor limit the potential for deformation analysis. With this paper we address the questions, if the trajectory estimation can be improved by the integration of known landmarks into the trajectory estimation procedure. Using a point cloud generated with an initial GNSS/IMU based trajectory, landmark targets can be observed in the point cloud and integrated into an updated estimate, using a factor graph-based approach. For the evaluation of a potential accuracy increase due to landmark observations, we performed measurements, comparing GNSS/IMU based results with the ones where landmarks are additionally integrated. The experiments show, that the accuracy increases especially in the heading angle, which is reflected in lower residuals to observed reference coordinates, but also in the trajectory covariances of the estimation results.
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Pham, Quang-Cuong, and Yoshihiko Nakamura. "Affine trajectory deformation for redundant manipulators." In Robotics: Science and Systems 2012. Robotics: Science and Systems Foundation, 2012. http://dx.doi.org/10.15607/rss.2012.viii.042.
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Delsart, V., and T. Fraichard. "Navigating dynamic environments using trajectory deformation." In 2008 IEEE/RSJ International Conference on Intelligent Robots and Systems. IEEE, 2008. http://dx.doi.org/10.1109/iros.2008.4650639.
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Singh, Arun Kumar, and Reza Ghabcheloo. "Trajectory Deformation Through Generalized Time Scaling." In 2018 17th European Control Conference (ECC). IEEE, 2018. http://dx.doi.org/10.23919/ecc.2018.8550056.
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Sun, Shih-Yu, Brian W. Anthony, and Matthew W. Gilbertson. "Trajectory-based deformation correction in ultrasound images." In SPIE Medical Imaging, edited by Jan D'hooge and Stephen A. McAleavey. SPIE, 2010. http://dx.doi.org/10.1117/12.844184.
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Justo, Victor Sillerico, and Fernando Santos Osorio. "A Trajectory Deformation Algorithm for Intelligent Vehicles." In 2022 Latin American Robotics Symposium (LARS), 2022 Brazilian Symposium on Robotics (SBR), and 2022 Workshop on Robotics in Education (WRE). IEEE, 2022. http://dx.doi.org/10.1109/lars/sbr/wre56824.2022.9995981.
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Dreier, Ansgar, Heiner Kuhlmann, and Lasse Klingbeil. "The potential of UAV-based Laser Scanning for Deformation Monitoring – Case Study on a Water Dam." In 5th Joint International Symposium on Deformation Monitoring. Editorial de la Universitat Politècnica de València, 2022. http://dx.doi.org/10.4995/jisdm2022.2022.13833.
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The use of unmanned aerial vehicles (UAV) in monitoring applications is constantly increasing due to the improvement in sensor technology and the associated higher accuracy that can be achieved. As a result, UAV-based laser scanning is already being used in various deformation monitoring applications such as the monitoring of landslides or land deformations. The main challenges, which also limit the accuracy of the resulting georeferenced point cloud are given by the trajectory estimation, the measurement environment and the flight planning. Difficult conditions and high accuracy demands are especially given for the monitoring of a water dam. While the use of area-based measurements such as terrestrial laser scanning (TLS) is an already established approach for such monitoring tasks, the use of a similar technology on a platform such as a UAV is promising and investigated in this study by acquiring a single measurement epoch at a water dam. In addition to the proposal of a flight pattern for the measurements, the trajectory estimation results are evaluated in detail. Due to critical GNSS conditions, positioning errors lead to systematic shifts between single flight strips. Subsequent optimization with known control points allows the point cloud to be compared to a TLS reference. The difference between the two is shown to have a mean difference of 5 mm with a 9.2 mm standard deviation. This can be considered a highly promising result, especially as the potential for further improvement by using additional targets and sensors (e.g. camera) has been identified.
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"REAL-TIME TRAJECTORY MODIFICATION BASED ON BÉZIER SHAPE DEFORMATION." In International Conference on Evolutionary Computation. SciTePress - Science and and Technology Publications, 2010. http://dx.doi.org/10.5220/0003086002430248.
Full textReports on the topic "Deformation trajectory"
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INVESTIGATING FATIGUE MECHANISMS AND CRACK GROWTH IN 20MNTIB STEEL HIGH-STRENGTH BOLTS: AN EXPERIMENTAL AND SIMULATION STUDY. The Hong Kong Institute of Steel Construction, 2023. http://dx.doi.org/10.18057/ijasc.2023.19.4.2.
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In this paper, axial-tensile, constant-amplitude fatigue experiments are performed on M24 high-strength bolts with grade 8.8 fabricated from 20MnTiB steel with a stress ratio (R) of 0.3, and their crack development is simulated. The stress range-fatigue life (S–N) curve is derived by using the experimental results. The fatigue mechanism is then investigated through strain and fractographic analyses. Moreover, the extended finite element method (XFEM) is applied for assessing the fatigue crack propagation behavior of the high-strength bolts. The findings reveal that the 20MnTiB steel bolt exhibits a threshold fatigue strength of 140.77 MPa at two million loading cycles, which is 1.68 times greater than the corresponding value for 35K steel bolts at the same stress ratio. The bolt's stable deformation stage constitutes 87% of its total fatigue life. The XFEM is capable of accurately predicting the fatigue crack propagation trajectory and the lifespan of the high-strength bolts. Our analysis indicates that the crack initially propagates predominantly along the bolt's circumferential direction, accounting for 85% of the overall crack propagation life, before transitioning to unstable growth and experiencing an exponential increase in length.