Pub Date : 2025-12-17DOI: 10.1016/j.mechmachtheory.2025.106320
M. Verotti
Recently, the instantaneous geometric invariants have proved to be a fundamental tool for the analysis of the motion generated by flexure hinges. In this paper, the invariants are applied to the synthesis of compliant mechanisms at the output port level. The motion of the moving plane associated to the output port is described through fundamental geometric entities, that are the inflection circle, the cubic of stationary curvature, and its derivative. The proposed synthesis procedure aims to reshape the output port to embody the special points on the plane, that are the Ball’s and the Burmester’s points, approximating straight and circular paths to the third and to the fourth order, respectively. The method is implemented for the design of a compliant mechanism and numerical simulations are conducted to verify the theoretical results. A discussion of the advantages and disadvantages of the method is presented.
{"title":"Synthesis at the output port of compliant mechanisms through the instantaneous geometric invariants","authors":"M. Verotti","doi":"10.1016/j.mechmachtheory.2025.106320","DOIUrl":"10.1016/j.mechmachtheory.2025.106320","url":null,"abstract":"<div><div>Recently, the instantaneous geometric invariants have proved to be a fundamental tool for the analysis of the motion generated by flexure hinges. In this paper, the invariants are applied to the synthesis of compliant mechanisms at the output port level. The motion of the moving plane associated to the output port is described through fundamental geometric entities, that are the inflection circle, the cubic of stationary curvature, and its derivative. The proposed synthesis procedure aims to reshape the output port to embody the special points on the plane, that are the Ball’s and the Burmester’s points, approximating straight and circular paths to the third and to the fourth order, respectively. The method is implemented for the design of a compliant mechanism and numerical simulations are conducted to verify the theoretical results. A discussion of the advantages and disadvantages of the method is presented.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"219 ","pages":"Article 106320"},"PeriodicalIF":4.5,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145790360","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-16DOI: 10.1016/j.mechmachtheory.2025.106317
Pello Alberdi, Aitor Arana, Aitor Oyanguren, Jon Larrañaga, Ibai Ulacia
Ball screw mechanisms are widely used in precision applications due to their high stiffness and efficiency. However, unlike ball bearings, the helical geometry of ball screws leads to multidirectional contact kinematics, which significantly influence friction, wear, and overall performance. In the classical contact kinematic formulation, the velocity components of the ball are not fully projected onto the contact interface, resulting in significant errors in the calculation of contact kinematics.
This work presents a revised contact kinematic formulation considering all the missing components, and revealing substantial differences in the prediction which alters the conventional understanding of contact kinematics in ball screws. The contact kinematics are broken down into their fundamental components-rolling, side, and spinning slip-and analytical expressions for each are introduced. A new characterisation framework based on three independent variables is proposed, quantifying the distinct effects of rolling, side, and spinning motion more comprehensively than traditional single SRR.
The proposed model is first validated against a well-established ball bearing formulation (i.e. ball screw with no lead), confirming its accuracy under such geometry. At the ball screw scale, the results reveal substantial deviations from existing models. Side slip emerges as the dominant mechanism, fundamentally revising the conventional interpretation of contact kinematics. Furthermore, the new three-variable framework enables a more complete and accurate characterisation of the contact behaviour, offering valuable insights for tribological modelling and performance optimisation. Finally, a parametric analysis is conducted to examine the influence of key kinematic constraints on the sliding behaviour, highlighting the independent role of each in defining the contact kinematics.
{"title":"A revised framework for ball-screw contact kinematics","authors":"Pello Alberdi, Aitor Arana, Aitor Oyanguren, Jon Larrañaga, Ibai Ulacia","doi":"10.1016/j.mechmachtheory.2025.106317","DOIUrl":"10.1016/j.mechmachtheory.2025.106317","url":null,"abstract":"<div><div>Ball screw mechanisms are widely used in precision applications due to their high stiffness and efficiency. However, unlike ball bearings, the helical geometry of ball screws leads to multidirectional contact kinematics, which significantly influence friction, wear, and overall performance. In the classical contact kinematic formulation, the velocity components of the ball are not fully projected onto the contact interface, resulting in significant errors in the calculation of contact kinematics.</div><div>This work presents a revised contact kinematic formulation considering all the missing components, and revealing substantial differences in the prediction which alters the conventional understanding of contact kinematics in ball screws. The contact kinematics are broken down into their fundamental components-rolling, side, and spinning slip-and analytical expressions for each are introduced. A new characterisation framework based on three independent variables is proposed, quantifying the distinct effects of rolling, side, and spinning motion more comprehensively than traditional single <em>SRR</em>.</div><div>The proposed model is first validated against a well-established ball bearing formulation (i.e. ball screw with no lead), confirming its accuracy under such geometry. At the ball screw scale, the results reveal substantial deviations from existing models. Side slip emerges as the dominant mechanism, fundamentally revising the conventional interpretation of contact kinematics. Furthermore, the new three-variable framework enables a more complete and accurate characterisation of the contact behaviour, offering valuable insights for tribological modelling and performance optimisation. Finally, a parametric analysis is conducted to examine the influence of key kinematic constraints on the sliding behaviour, highlighting the independent role of each in defining the contact kinematics.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"219 ","pages":"Article 106317"},"PeriodicalIF":4.5,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145790363","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-16DOI: 10.1016/j.mechmachtheory.2025.106322
Yu Liu , Xinyuan Li , Hao Liu , Hui Ma
This study investigates the coupled deformation mechanism and time-varying meshing stiffness of thin-walled ring gears with integrated idler gear bearings in aerospace planetary transmission systems. Based on a self-balanced virtual support model and thin-walled ring theory, influence coefficient formulas for the radial displacement and rotation at the gear root were derived, and an analytical model of ring gear deformation considering roller phase relations was established. By formulating the nonlinear relationship between radial displacement, rotation, and roller rotation angle, a foundation stiffness model of the gear–idler gear bearing system was developed. Furthermore, a time-varying meshing stiffness model was proposed using the potential energy method. Comparison with finite element results validated the proposed approach. The findings reveal that roller support significantly enhances the ring gear foundation stiffness; an increased speed ratio between the cage and ring gear increases meshing stiffness, whereas a higher roller rotational speed increases stiffness due to centrifugal effects. This work provides theoretical guidance for stiffness optimization and dynamic design of thin-walled ring gear planetary systems with idler gear bearings.
{"title":"Time-varying meshing stiffness model of the idler ring bearing in planetary gear train","authors":"Yu Liu , Xinyuan Li , Hao Liu , Hui Ma","doi":"10.1016/j.mechmachtheory.2025.106322","DOIUrl":"10.1016/j.mechmachtheory.2025.106322","url":null,"abstract":"<div><div>This study investigates the coupled deformation mechanism and time-varying meshing stiffness of thin-walled ring gears with integrated idler gear bearings in aerospace planetary transmission systems. Based on a self-balanced virtual support model and thin-walled ring theory, influence coefficient formulas for the radial displacement and rotation at the gear root were derived, and an analytical model of ring gear deformation considering roller phase relations was established. By formulating the nonlinear relationship between radial displacement, rotation, and roller rotation angle, a foundation stiffness model of the gear–idler gear bearing system was developed. Furthermore, a time-varying meshing stiffness model was proposed using the potential energy method. Comparison with finite element results validated the proposed approach. The findings reveal that roller support significantly enhances the ring gear foundation stiffness; an increased speed ratio between the cage and ring gear increases meshing stiffness, whereas a higher roller rotational speed increases stiffness due to centrifugal effects. This work provides theoretical guidance for stiffness optimization and dynamic design of thin-walled ring gear planetary systems with idler gear bearings.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"219 ","pages":"Article 106322"},"PeriodicalIF":4.5,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145790361","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-16DOI: 10.1016/j.mechmachtheory.2025.106321
Zheng Chen, Hui Ren, Ping Zhou, Wei Fan
Three-dimensional (3D) beam structures with large deformations and sliding boundaries face critical challenges in balancing accuracy and computational efficiency. To overcome these limitations, a novel globally discretized Arbitrary Lagrangian-Eulerian beam model is proposed for 3D large deformation dynamic analysis. Analytical assumed modes of sectional angles and strains are adopted for global discretization, capturing complex deformations with minimal degrees of freedom. Explicit derivations of both configurational forces and governing equations for large overall motions are achieved. An explicit integration scheme with updating rotation on the SO(3) manifold is proposed to efficiently solve the weak stiff equations of slender cables. An implicit integration scheme is adopted for thick beams with full strain consideration, where analytically derived Jacobian matrices are utilized to enhance computational performance. Numerical results show that the present model demonstrates >80 % reduction in degrees of freedom while maintaining high accuracy. Its efficacy is further proven through the cable-driven parallel robots, achieving real-time capability for large-scale applications. The current approach shows promising potential for modeling other sliding-boundary systems, such as concentric-tube soft robots and variable-length space manipulators.
{"title":"A globally discretized ALE beam model for cable-driven parallel robots with large deformations","authors":"Zheng Chen, Hui Ren, Ping Zhou, Wei Fan","doi":"10.1016/j.mechmachtheory.2025.106321","DOIUrl":"10.1016/j.mechmachtheory.2025.106321","url":null,"abstract":"<div><div>Three-dimensional (3D) beam structures with large deformations and sliding boundaries face critical challenges in balancing accuracy and computational efficiency. To overcome these limitations, a novel globally discretized Arbitrary Lagrangian-Eulerian beam model is proposed for 3D large deformation dynamic analysis. Analytical assumed modes of sectional angles and strains are adopted for global discretization, capturing complex deformations with minimal degrees of freedom. Explicit derivations of both configurational forces and governing equations for large overall motions are achieved. An explicit integration scheme with updating rotation on the SO(3) manifold is proposed to efficiently solve the weak stiff equations of slender cables. An implicit integration scheme is adopted for thick beams with full strain consideration, where analytically derived Jacobian matrices are utilized to enhance computational performance. Numerical results show that the present model demonstrates >80 % reduction in degrees of freedom while maintaining high accuracy. Its efficacy is further proven through the cable-driven parallel robots, achieving real-time capability for large-scale applications. The current approach shows promising potential for modeling other sliding-boundary systems, such as concentric-tube soft robots and variable-length space manipulators.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"219 ","pages":"Article 106321"},"PeriodicalIF":4.5,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145790362","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-13DOI: 10.1016/j.mechmachtheory.2025.106298
Luigi Romano, Sweden Linköping
{"title":"Corrigendum to “Kinematics of rolling contact: Derivation, misconceptions, and generalisations” [Mechanism and Machine Theory 216 (2025) 106201]","authors":"Luigi Romano, Sweden Linköping","doi":"10.1016/j.mechmachtheory.2025.106298","DOIUrl":"10.1016/j.mechmachtheory.2025.106298","url":null,"abstract":"","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"219 ","pages":"Article 106298"},"PeriodicalIF":4.5,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145925079","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-13DOI: 10.1016/j.mechmachtheory.2025.106319
Tiancheng Ouyang , Hongyang Tian , Yang Yang , Shaohui Qin , Yong Chen
In high-speed gear transmissions, cavitation is prone to occur, leading to vibration deterioration and tooth surface erosion. Vibration and engagement characteristics become abnormal when misalignment inevitably occurs due to mounting errors, deformation and long-term wear. However, current gear cavitation studies are set to ideal alignment and it is not clear how misalignment affects cavitation. To investigate the cavitation mechanism in misaligned gears, a kinetic model of misaligned gears is combined with a turbulence model with cavitation for the first time. First, the abnormal vibration responses that derived from the gear finite element model are validated against existing experimental results, and they are applied as boundary rotation conditions for the flow field. Subsequently, the effects of vibration and meshing discrepancies caused by different misalignments on cavitation are comprehensively analyzed. Vapor and pressure distributions in the meshing zone are examined to evaluate the impacts of misalignment degree, rotational speed, vibration, and tooth surface meshing. Results indicate that gear pairs with misalignment exhibit significant cavitation phenomena during high-speed operation. Specifically, vibration amplification induced by radial and yaw misalignments exacerbate the severity of cavitation.
{"title":"Cavitation mechanism of high-speed gears with misalignment","authors":"Tiancheng Ouyang , Hongyang Tian , Yang Yang , Shaohui Qin , Yong Chen","doi":"10.1016/j.mechmachtheory.2025.106319","DOIUrl":"10.1016/j.mechmachtheory.2025.106319","url":null,"abstract":"<div><div>In high-speed gear transmissions, cavitation is prone to occur, leading to vibration deterioration and tooth surface erosion. Vibration and engagement characteristics become abnormal when misalignment inevitably occurs due to mounting errors, deformation and long-term wear. However, current gear cavitation studies are set to ideal alignment and it is not clear how misalignment affects cavitation. To investigate the cavitation mechanism in misaligned gears, a kinetic model of misaligned gears is combined with a turbulence model with cavitation for the first time. First, the abnormal vibration responses that derived from the gear finite element model are validated against existing experimental results, and they are applied as boundary rotation conditions for the flow field. Subsequently, the effects of vibration and meshing discrepancies caused by different misalignments on cavitation are comprehensively analyzed. Vapor and pressure distributions in the meshing zone are examined to evaluate the impacts of misalignment degree, rotational speed, vibration, and tooth surface meshing. Results indicate that gear pairs with misalignment exhibit significant cavitation phenomena during high-speed operation. Specifically, vibration amplification induced by radial and yaw misalignments exacerbate the severity of cavitation.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"219 ","pages":"Article 106319"},"PeriodicalIF":4.5,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145790364","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-11DOI: 10.1016/j.mechmachtheory.2025.106316
Bo Wang , Qing Wu , Hailiang Yu , Weihua Ma , Feng Lin , Xiangyu Li , Xueqiang Zhang
To analyze the derailment mechanism of a subway train under air spring failure conditions and to identify improvement measures, this study first establishes a dynamic train model according to the actual train formation. Subsequently, equivalent models for air spring failure are introduced. Finally, based on wheel–rail derailment theory and vehicle system dynamics, a comparative analysis is conducted under both normal (inflated) and failed air spring conditions to investigate key factors influencing the derailment mechanism. Corresponding improvement measures are then proposed. The results indicate that: (1) with air spring failure, curve transition derails the train; (2) multiple factors can effectively lower derailment risks; (3) large lateral creep force and attack angle are not necessary conditions for flange climbing; and (4) installing guard rails at curve exits and applying lubrication to the rails can effectively reduce flange climbing risk under air spring failure. This study provides valuable insights for subway track design and for mitigating derailment risks in the event of air spring failure.
{"title":"Derailment mechanism analysis of subway vehicles under air spring failure","authors":"Bo Wang , Qing Wu , Hailiang Yu , Weihua Ma , Feng Lin , Xiangyu Li , Xueqiang Zhang","doi":"10.1016/j.mechmachtheory.2025.106316","DOIUrl":"10.1016/j.mechmachtheory.2025.106316","url":null,"abstract":"<div><div>To analyze the derailment mechanism of a subway train under air spring failure conditions and to identify improvement measures, this study first establishes a dynamic train model according to the actual train formation. Subsequently, equivalent models for air spring failure are introduced. Finally, based on wheel–rail derailment theory and vehicle system dynamics, a comparative analysis is conducted under both normal (inflated) and failed air spring conditions to investigate key factors influencing the derailment mechanism. Corresponding improvement measures are then proposed. The results indicate that: (1) with air spring failure, curve transition derails the train; (2) multiple factors can effectively lower derailment risks; (3) large lateral creep force and attack angle are not necessary conditions for flange climbing; and (4) installing guard rails at curve exits and applying lubrication to the rails can effectively reduce flange climbing risk under air spring failure. This study provides valuable insights for subway track design and for mitigating derailment risks in the event of air spring failure.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"219 ","pages":"Article 106316"},"PeriodicalIF":4.5,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145737135","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-10DOI: 10.1016/j.mechmachtheory.2025.106315
Madalena Antunes, João Folgado, Carlos Quental
The formulation of rotational driving constraints using angular variables (angle-based formulation) may introduce numerical instabilities and redundancy among kinematic constraints, which can compromise the robustness of multibody analyses. This study proposes an alternative Euler-based formulation, in which Euler parameters, describing the relative orientation between joint-connected bodies, are used to define rotational driving constraints. This formulation avoids singularities, enables full range of motion evaluation, and eliminates redundancy. Both angled-based and Euler-based formulations were applied to different joints within both open and closed kinematic chains using an in-house multibody model of the human body. Kinematic and inverse dynamic analyses were conducted across several movements from multiple subjects, and the results were compared between the two formulations and literature data. The Euler-based formulation provided independent kinematic constraints and showed good agreement with joint kinematics and torques from established methods. In addition, it improved computational efficiency. Overall, the use of Euler parameters offers a robust and efficient alternative to angle-based formulations for rotational driving constraints in multibody system dynamics.
{"title":"Driving rotational motion with Euler parameters: a constraint formulation for multibody systems","authors":"Madalena Antunes, João Folgado, Carlos Quental","doi":"10.1016/j.mechmachtheory.2025.106315","DOIUrl":"10.1016/j.mechmachtheory.2025.106315","url":null,"abstract":"<div><div>The formulation of rotational driving constraints using angular variables (angle-based formulation) may introduce numerical instabilities and redundancy among kinematic constraints, which can compromise the robustness of multibody analyses. This study proposes an alternative Euler-based formulation, in which Euler parameters, describing the relative orientation between joint-connected bodies, are used to define rotational driving constraints. This formulation avoids singularities, enables full range of motion evaluation, and eliminates redundancy. Both angled-based and Euler-based formulations were applied to different joints within both open and closed kinematic chains using an in-house multibody model of the human body. Kinematic and inverse dynamic analyses were conducted across several movements from multiple subjects, and the results were compared between the two formulations and literature data. The Euler-based formulation provided independent kinematic constraints and showed good agreement with joint kinematics and torques from established methods. In addition, it improved computational efficiency. Overall, the use of Euler parameters offers a robust and efficient alternative to angle-based formulations for rotational driving constraints in multibody system dynamics.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"219 ","pages":"Article 106315"},"PeriodicalIF":4.5,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145737134","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-06DOI: 10.1016/j.mechmachtheory.2025.106306
Jun Cai , Wang Yu , Bing Li , Sen Wang , Fujun Peng
This paper presents a general type synthesis methodology for reconfigurable single-loop mechanisms (RSLMs). Unlike conventional approaches that derive RSLMs from classical configurations, this study investigates constraint system variations during transitional configurations of RSLMs. When the RSLM is in transitional configuration, the order of wrench systems reaches its peak. Utilizing this characteristic, we categorize wrench systems according to their order and type, then construct the original single-loop mechanism through the closure of the corresponding wrench system's open-loop kinematic chains. Subsequently, while maintaining the original wrench system configuration, kinematic pairs are added. Further analysis of inactive joints and mechanism reconfiguration characteristics, the optimized RSLM configuration is synthesized. The proposed method generates more generalized RSLM configurations and ensures that the RSLM created is in transitional configurations, thereby facilitating subsequent motion pattern analysis. As validation, multiple novel 6R and 7R RSLMs with single DOF reconfigurability have been successfully synthesized, demonstrating the method's feasibility and effectiveness. Finally, optimization strategies for eliminating inactive joints and structural refinement are proposed. Two application-oriented prototypes are presented to exemplify the practical potential of the synthesized RSLMs.
{"title":"Type synthesis of reconfigurable single-loop mechanisms based on transitional configurations","authors":"Jun Cai , Wang Yu , Bing Li , Sen Wang , Fujun Peng","doi":"10.1016/j.mechmachtheory.2025.106306","DOIUrl":"10.1016/j.mechmachtheory.2025.106306","url":null,"abstract":"<div><div>This paper presents a general type synthesis methodology for reconfigurable single-loop mechanisms (RSLMs). Unlike conventional approaches that derive RSLMs from classical configurations, this study investigates constraint system variations during transitional configurations of RSLMs. When the RSLM is in transitional configuration, the order of wrench systems reaches its peak. Utilizing this characteristic, we categorize wrench systems according to their order and type, then construct the original single-loop mechanism through the closure of the corresponding wrench system's open-loop kinematic chains. Subsequently, while maintaining the original wrench system configuration, kinematic pairs are added. Further analysis of inactive joints and mechanism reconfiguration characteristics, the optimized RSLM configuration is synthesized. The proposed method generates more generalized RSLM configurations and ensures that the RSLM created is in transitional configurations, thereby facilitating subsequent motion pattern analysis. As validation, multiple novel 6R and 7R RSLMs with single DOF reconfigurability have been successfully synthesized, demonstrating the method's feasibility and effectiveness. Finally, optimization strategies for eliminating inactive joints and structural refinement are proposed. Two application-oriented prototypes are presented to exemplify the practical potential of the synthesized RSLMs.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"219 ","pages":"Article 106306"},"PeriodicalIF":4.5,"publicationDate":"2025-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145685305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-04DOI: 10.1016/j.mechmachtheory.2025.106301
Min Liu , Liwen Lu , Jinqing Zhan , Benliang Zhu , Hua Wang , Xianmin Zhang
This paper proposes a single explicit topology optimization method based on the moving morphable component framework for the integrated design of the movable components and compliant mechanism. The core of this method lies in the unified use of explicit geometric parameters (size and pose) to describe the topological configuration and layout of the mechanism and embedded components, avoiding the model complexity and dual sensitivity analysis issues associated with hybrid description frameworks. Based on this unified description framework, a topological description function for the compliant mechanism with embedded components is constructed, and finite element analysis is performed using the ersatz material model. Under the volume constraint of the host structure, an optimization model is established with the goal of maximizing the output displacement. Sensitivity analysis is done analytically, and the design variables are updated using the method of moving asymptotes approach. Numerical examples verify the effectiveness of this method in the integrated design of embedded components and compliant mechanisms.
{"title":"Layout optimization of compliant mechanism with embedded components using moving morphable component (MMC) method","authors":"Min Liu , Liwen Lu , Jinqing Zhan , Benliang Zhu , Hua Wang , Xianmin Zhang","doi":"10.1016/j.mechmachtheory.2025.106301","DOIUrl":"10.1016/j.mechmachtheory.2025.106301","url":null,"abstract":"<div><div>This paper proposes a single explicit topology optimization method based on the moving morphable component framework for the integrated design of the movable components and compliant mechanism. The core of this method lies in the unified use of explicit geometric parameters (size and pose) to describe the topological configuration and layout of the mechanism and embedded components, avoiding the model complexity and dual sensitivity analysis issues associated with hybrid description frameworks. Based on this unified description framework, a topological description function for the compliant mechanism with embedded components is constructed, and finite element analysis is performed using the ersatz material model. Under the volume constraint of the host structure, an optimization model is established with the goal of maximizing the output displacement. Sensitivity analysis is done analytically, and the design variables are updated using the method of moving asymptotes approach. Numerical examples verify the effectiveness of this method in the integrated design of embedded components and compliant mechanisms.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"219 ","pages":"Article 106301"},"PeriodicalIF":4.5,"publicationDate":"2025-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145685307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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