{"title":"Advanced sealing technology in mechanical systems with magnetorheological fluid for large gap applications","authors":"Yurui Shen, Qiyu Wang, Lai Peng, Dezheng Hua, Xinhua Liu, Zhixiong Li, Sumika Chauhan, Govind Vashishtha","doi":"10.1007/s11012-025-01988-2","DOIUrl":"10.1007/s11012-025-01988-2","url":null,"abstract":"<div><p>Sealing technology is critical for the reliability and efficiency of mechanical systems, especially in rotating shaft applications. Traditional ferrofluid (FF) seals, while effective in narrow gaps (0.1–0.3 mm), face significant limitations in maintaining effective sealing under large gap conditions (more than 0.3 mm). To address this challenge, a magnetorheological fluid (MRF) seal optimized for high-speed dynamic applications was proposed. Firstly, a sealing structure was designed, and the rheological properties of MRF were characterized. Then, theoretical models for both FF and MRF seals were derived to analyze their operating principles and performance differences. A custom test bench was constructed to evaluate static sealing performance at 0.1 mm and 0.4 mm gaps and dynamic sealing performance at shear velocities of 0.2, 0.4, 0.6, 0.8, and 1.0 m/s. Experimental results demonstrated that MRF seals achieve higher pressure differentials compared to FF seals, particularly in large gap scenarios. These findings suggest that MRF seals offer a promising alternative for advanced sealing applications in mechanical systems.</p></div>","PeriodicalId":695,"journal":{"name":"Meccanica","volume":"60 5","pages":"1201 - 1213"},"PeriodicalIF":2.1,"publicationDate":"2025-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145164242","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
MeccanicaPub Date : 2025-05-07DOI: 10.1007/s11012-025-01957-9
Sergei Chernyshenko
{"title":"Energy dissipation bounds for flows in pipes and past bodies of general geometry","authors":"Sergei Chernyshenko","doi":"10.1007/s11012-025-01957-9","DOIUrl":"10.1007/s11012-025-01957-9","url":null,"abstract":"<div><p>The problem considered can in general be described as the problem of proving rigorously that as the Reynolds number of a fluid flow tends to infinity, the drag coefficient remains bounded. It has been proven for flows in domains of certain, rather restrictive, set of geometries, but not in general. The drag is the sum of the pressure drag and friction drag. In essence, this paper gives a proof that the friction drag coefficient does remain bounded. Rather nontrivial implications of this result are discussed.</p></div>","PeriodicalId":695,"journal":{"name":"Meccanica","volume":"60 8","pages":"2475 - 2486"},"PeriodicalIF":2.1,"publicationDate":"2025-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11012-025-01957-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145230454","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
MeccanicaPub Date : 2025-05-05DOI: 10.1007/s11012-025-01987-3
Hung Van Le, Hieu Giang Le, Thanh-Phong Dao
{"title":"Kinetostatic, dynamic, trajectory modeling for a new grasshopper-inspired 2DOF compliant mechanism for non-resonant vibration-assisted polishing","authors":"Hung Van Le, Hieu Giang Le, Thanh-Phong Dao","doi":"10.1007/s11012-025-01987-3","DOIUrl":"10.1007/s11012-025-01987-3","url":null,"abstract":"<div><p>In vibration-assisted polishing (VAP), static, kinetostatic, dynamics, and vibration trajectories are extremely important characteristics for compliant mechanisms to generate the vibrating source, but these behaviors lack a systematic modeling theory. This study presents a new XY compliant mechanism design inspired by the grasshopper. The proposed design can provide a wide amplitude amplification by a new self-amplified stroke based on the grasshopper’s legs. The machining qualities of VAP are crucially dependent on the vibrating amplitude, the output force, and the vibration trajectory of the central table. This research is aimed at providing theoretical modeling of the static, kinetostatic, dynamic, and oscillatory trajectories of the suggested structure. The stroke amplification ratio, workspace, stress, and kinetostatic are theoretically formulated by a graphical method and free body diagram. The resonant working frequency of the mechanism is modeled Lagrange’s II method. The dynamic motion and vibration trajectory of the mechanism in two directions are theoretically derived using D’Alembert’s principle. The force ratio between the input and output of the vibrating table is theoretically calculated. The results obtained from the theory closely align with those from the finite element analysis. The results found that the proposed mechanism can work at a wide workspace of 736.6 × 736.6 μm, a large stroke amplification ratio of 4.53, and a high working frequency of 548 Hz. The experimental tests are matched with the theoretical ones. This novel design facilitates a comprehensive design and modeling synthesis for two-dimensional vibrating mechanism for VAP.</p></div>","PeriodicalId":695,"journal":{"name":"Meccanica","volume":"60 5","pages":"1173 - 1199"},"PeriodicalIF":2.1,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145162604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
MeccanicaPub Date : 2025-04-30DOI: 10.1007/s11012-025-01977-5
Yahroun Fei Long Hermans, Karim Ehab Moustafa Kamel, Olivier Debeir, Gabriele Milani, Thierry Jacques Massart
{"title":"Image-based structural kinematic limit analysis for historical masonry structures","authors":"Yahroun Fei Long Hermans, Karim Ehab Moustafa Kamel, Olivier Debeir, Gabriele Milani, Thierry Jacques Massart","doi":"10.1007/s11012-025-01977-5","DOIUrl":"10.1007/s11012-025-01977-5","url":null,"abstract":"<div><p>Evaluating the state of historical masonry structures, particularly those built with irregular masonry, presents challenges in determining their load-bearing capacity. Most current approaches use macroscopic numerical models that treat the material as a homogeneous continuum, where defining an appropriate constitutive law is essential. To this end, homogenization has proven useful in bridging the gap between meso and macro-scales, yet using homogenized macromodels may prevent to capture specific failure modes. Alternatively, mesoscopic methodologies represent stacking modes explicitly. However, full structural analysis at this scale has mainly been applied to regular masonry due to the complexities of explicitly representing the geometry of the irregular stones. The present contribution aims to propose a method that leverages image acquisition techniques, such as orthophotos, to address these challenges. Mortar joints are lumped onto zero-thickness interfaces, determined through a distance field-based morphing procedure and medial axis principles. The load-bearing capacity is assessed using a Kinematic Limit Analysis problem, formulated and solved as a linear programming problem. A Mohr-Coulomb frictional behavior, modified with a tensile cut-off and a linearized compression cap, is assigned to the mortar joints. The blocks are considered infinitely rigid and strong. It is shown that the proposed methodology can efficiently model structures of large sizes, by illustrating its use on two 2D problems.</p></div>","PeriodicalId":695,"journal":{"name":"Meccanica","volume":"60 7","pages":"2107 - 2124"},"PeriodicalIF":2.1,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144888079","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
MeccanicaPub Date : 2025-04-26DOI: 10.1007/s11012-025-01973-9
Matteo Lenti, Giulia Pomaranzi, Paolo Schito, Paolo Pennacchi, Alberto Zasso
{"title":"Dynamics of an aerial cableway through a time-varying meshing finite element approach","authors":"Matteo Lenti, Giulia Pomaranzi, Paolo Schito, Paolo Pennacchi, Alberto Zasso","doi":"10.1007/s11012-025-01973-9","DOIUrl":"10.1007/s11012-025-01973-9","url":null,"abstract":"<div><p>Cableways have been used intensively for transportation of goods and people since the early nineteenth century. Aerial cableways are primarily modelled based on a continuous representation, well-suited for traditional analytical models. However, due to the increasing complexity of these systems, cableway modeling is evolving to discretised approaches like Finite Element (FE) analysis. The Finite Element Method (FEM) is an alternative to the modal approach for studying the dynamics of nonlinear systems, and it is more suitable for the representation of large displacements needed in the view of the modeling of an entire plant; it is also flexible and computationally accurate. Dynamic models of aerial cableways based on finite element computation with significant geometry changes are currently lacking in the literature. The main purpose of this study is to fill this gap, through the development of a finite element model which is able to describe the dynamic behavior of aerial cableway, keeping into account its time-varying geometry. The system modelling is based on two cables (carrying and hauling), describing a back-and-forth aerial cableway to which a concentrated mass representing the cabin is added. After the introduction of the modelling approach, the finite element model is applied to investigate typical conditions such facilities are exposed to, i.e. overlapping between the hauling and the carrying cables or the large vibrations the hauling cable is subjected to, when the cabin is approaching the station. Versatility and ease of implementation are the main strength of the proposed model, making it suitable to further extensions.</p></div>","PeriodicalId":695,"journal":{"name":"Meccanica","volume":"60 5","pages":"1149 - 1172"},"PeriodicalIF":2.1,"publicationDate":"2025-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11012-025-01973-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145169188","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
MeccanicaPub Date : 2025-04-25DOI: 10.1007/s11012-025-01982-8
Uma Shankar, Anand Bhushan
{"title":"Static and dynamic characteristics of electrostatically actuated elliptical cross-section beams for NEMS applications","authors":"Uma Shankar, Anand Bhushan","doi":"10.1007/s11012-025-01982-8","DOIUrl":"10.1007/s11012-025-01982-8","url":null,"abstract":"<div><p>In this study, we investigate the static and dynamic characteristics of electrostatically actuated nanobeams with elliptical cross-sections, focusing on their potential applications in nano-electromechanical systems (NEMS). Using finite element analysis (FEA) in COMSOL Multiphysics, we explore the effects of key parameters on the nanobeams’ performance. Our analysis includes a detailed examination of the static characteristic curves and natural frequencies under varying conditions. The study reveals significant insights into the behaviour of elliptical nanobeams, demonstrating how alterations in eccentricity and tilt angle influence the operational efficiency of NEMS devices. The impact of geometric variations on vibrational modes provide critical guidelines for designing robust and precise NEMS sensors and actuators.</p></div>","PeriodicalId":695,"journal":{"name":"Meccanica","volume":"60 5","pages":"1137 - 1148"},"PeriodicalIF":2.1,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145168503","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
MeccanicaPub Date : 2025-04-21DOI: 10.1007/s11012-025-01972-w
Yuki Chikahiro, Seiya Zenzai, Ichiro Ario
{"title":"A new formula for estimation of vertical natural frequency for a scissors-type bridge through hammering tests and numerical simulation","authors":"Yuki Chikahiro, Seiya Zenzai, Ichiro Ario","doi":"10.1007/s11012-025-01972-w","DOIUrl":"10.1007/s11012-025-01972-w","url":null,"abstract":"<div><p>A scissors-type bridge that applies a deployable scissors mechanism to its structural form has been researched and developed to support emergency restoration activities after disasters. The vibration characteristics of this bridge have been evaluated by eigenvalue analysis and walking experiments in past studies. However, the basic knowledge, including the design method for this bridge, was still limited. Hence, this study conducts a hammering test to obtain basic vibration characteristics and explore the change in vibration characteristics under different boundary conditions through eigenvalue analysis. Although the total weight is increased by installing the decks, it can be seen that installing the decks on the top or bottom of the scissors-type bridge significantly improves rigidity in the horizontal direction. Still, the influence in the vertical direction is less than that in the horizontal direction. Furthermore, based on the experimental and numerical results, an estimation formula for the natural frequency approximating a scissors-type bridge as a simple beam structure was proposed. It was possible to estimate the natural frequencies in the vertical primary mode with errors of less than 3<span>(%)</span> compared with the experimental results and errors of less than 10<span>(%)</span> compared with the numerical results. This finding has important implications for the developing a simple and reliable design of emergency structures that use the scissor mechanism.</p></div>","PeriodicalId":695,"journal":{"name":"Meccanica","volume":"60 8","pages":"2345 - 2360"},"PeriodicalIF":2.1,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11012-025-01972-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145230377","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Energy-based analysis of the capillary rise and meniscus dynamics upon pinning at the exit of a capillary tube","authors":"Changli Wang, Lifeng Dong, Junfeng Xiao, Jianfeng Xu","doi":"10.1007/s11012-025-01978-4","DOIUrl":"10.1007/s11012-025-01978-4","url":null,"abstract":"<div><p>The capillary imbibition phenomenon has been widely studied by establishing governing equations, some of which might be too complex to obtain accurate solutions. Moreover, the capillary rise can be influenced by the constraint of capillary edge (i.e., pinning phenomenon), which is difficult to describe by governing equations. Therefore, a new analysis method is proposed in this paper, which can predict the capillary rise with/without contact line movement considering the dynamic contact angle and entrance viscosity dissipation. Firstly, the capillary length is discretized into micro elements. Secondly, every micro fluid level rise is analyzed based on conservation of mechanical energy. Finally, the whole rise process can be predicted by the end-to-end linking of all micro-elements. The accuracy of the proposed method is verified by multiple sets of experimental data. Moreover, we discuss the pinning and depinning phenomena in detail and propose a dimensionless number to judge the occurrence of depinning phenomena.</p></div>","PeriodicalId":695,"journal":{"name":"Meccanica","volume":"60 5","pages":"1115 - 1136"},"PeriodicalIF":2.1,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145166101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
MeccanicaPub Date : 2025-04-17DOI: 10.1007/s11012-025-01980-w
Junqi Jiang, Shun Weng, Hao Luo, Hongping Zhu
{"title":"Optimal design of a novel tuned mass rate-independent damper for structural vibration suppression","authors":"Junqi Jiang, Shun Weng, Hao Luo, Hongping Zhu","doi":"10.1007/s11012-025-01980-w","DOIUrl":"10.1007/s11012-025-01980-w","url":null,"abstract":"<div><p>In the present study, a novel type of nontraditional tuned mass damper (TMD), termed as a tuned mass rate-independent damper (TMRD), was proposed for structural vibration suppression. The proposed TMRD consisted of a spring element, a mass element, and a rate-independent linear damping (RILD) element, which generated damping forces independent of the excitation frequencies. Based on the fixed-point theory, analytical formula of optimally designing the characteristic parameters of the TMRD were derived. The advantages of the TMRD over TMDs in suppressing the structural vibration and damper stroke were demonstrated, when they were separately used in flexible structures subjected to harmonic and earthquake-induced ground motions. For practical applications, an approximate method was presented to passively realize the proposed TMRD. It was suggested that the proposed method can be used to physically realize the TMRD and provide a superior solution than the conventional TMD to suppressing the structural vibration and damper stroke.</p></div>","PeriodicalId":695,"journal":{"name":"Meccanica","volume":"60 4","pages":"1099 - 1114"},"PeriodicalIF":1.9,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143896718","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
MeccanicaPub Date : 2025-04-15DOI: 10.1007/s11012-025-01979-3
Fei Hu, Biao Luo, Fu-hua He, Qiao Yang
{"title":"Research on the stiffness of spur gear pairs based on the improved energy method under multiple influencing factors","authors":"Fei Hu, Biao Luo, Fu-hua He, Qiao Yang","doi":"10.1007/s11012-025-01979-3","DOIUrl":"10.1007/s11012-025-01979-3","url":null,"abstract":"<div><p>To investigate the effects of axial misalignment, lead crown relief, and temperature on the meshing stiffness of gears, this study aims to derive high-precision gear stiffness values that are more aligned with practical engineering applications. Based on the thermal expansion theory, slice coupling effect, and involute profile theory, a thermal stiffness model for meshing spur gear pairs under multiple influencing factors has been established, integrating the improved potential energy method and the nonlinear contact stiffness calculation approach. A calculation method for the thermal stiffness of meshing spur gear pairs, considering the impacts of axial misalignment and lead crown relief, has been developed. Furthermore, the mechanisms by which varying temperature, modification amounts, and misalignment affect the meshing stiffness of spur gear pairs have been explored. The results indicate that both lead crown relief and axial misalignment alter the load distribution across the tooth width, leading to a relative load concentration and consequently affecting the deformation of the gears under external loading, thereby influencing their meshing stiffness. It was found that the meshing stiffness decreases with an increase in axial misalignment and lead crown relief amounts. Additionally, with the introduction of temperature effects, an increase in temperature further reduces the meshing stiffness of the gear pair. The thermal deformation induced by temperature variations results in profile errors, affecting the actual meshing positions of the gears and altering the dimensions of single and double tooth intervals along the meshing line. This research establishes a theoretical foundation for the design of gear systems and the study of gear transmission system dynamics.</p></div>","PeriodicalId":695,"journal":{"name":"Meccanica","volume":"60 4","pages":"1079 - 1097"},"PeriodicalIF":1.9,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143896760","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}