Pub Date : 2025-01-22DOI: 10.1016/j.ijmecsci.2025.110002
Shuo Liu, Lining Gao, Mingcai Xing, Yi Cui
To accurately simulate the high-frequency vibrations induced by piston slap in engines, a 3D multi-physics coupled model under a multibody dynamic framework has been developed, incorporating multi-physics interactions like mixed lubrication and heat transfer. This novel model is specifically designed to investigate the transmission characteristics of vibrations across solid-liquid-solid interfaces, which is the core focus of this study. The results, for the first time, demonstrate that vibration signals exhibit distinct phases when transmitted through a liquid medium, as revealed by model simulations and experimental analysis. Additionally, two primary pathways are identified for the transfer of vibrations to the engine surface, with broadband vibration energy predominantly concentrated in the 2,500–5,000 Hz frequency range.
{"title":"Vibration transmission in lubricated piston-liner systems: Experimental and multi-physics coupled analysis","authors":"Shuo Liu, Lining Gao, Mingcai Xing, Yi Cui","doi":"10.1016/j.ijmecsci.2025.110002","DOIUrl":"https://doi.org/10.1016/j.ijmecsci.2025.110002","url":null,"abstract":"To accurately simulate the high-frequency vibrations induced by piston slap in engines, a 3D multi-physics coupled model under a multibody dynamic framework has been developed, incorporating multi-physics interactions like mixed lubrication and heat transfer. This novel model is specifically designed to investigate the transmission characteristics of vibrations across solid-liquid-solid interfaces, which is the core focus of this study. The results, for the first time, demonstrate that vibration signals exhibit distinct phases when transmitted through a liquid medium, as revealed by model simulations and experimental analysis. Additionally, two primary pathways are identified for the transfer of vibrations to the engine surface, with broadband vibration energy predominantly concentrated in the 2,500–5,000 Hz frequency range.","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"23 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143049778","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 : 2025-01-22DOI: 10.1016/j.ijmecsci.2025.109986
Rashmiranjan Mohapatra, V. Narayanamurthy, M. Ramji, Sai Sidhardh
This paper presents an energy-based approach to develop a spring-based (semi-analytical) reduced-order model for the mechanical behavior (stiffness, load carrying capacity) of a hybrid (bonded/bolted) single-lap joint with carbon fiber-reinforced polymer (CFRP) laminates when subjected to tensile load. More clearly, the hybrid joint is modeled as an appropriate combination of springs, where their stiffnesses are determined with a deformation energy framework. The proposed model can predict the different failure modes in the hybrid joint with greater accuracy, starting with the disbond of the adhesive layer, followed by damage in CFRP laminates due to the bearing load via bolt, on subsequent loading. In this study, three CFRP ply orientations are considered, i.e., quasi-isotropic ([04590−45]s), uni-directional ([0]8), and cross-ply ([090]2s). The damage modes in the adhesive are modeled using a bilinear cohesive law, and those in CFRP laminates are modeled using Hashin’s damage initiation criteria. A linear degradation law is used to determine the degraded material properties of the CFRP laminate. The individual spring stiffnesses are solved by a developed 2D FE solver. The proposed framework is validated with commercial 3D FEA and experimental studies. Finally, certain design recommendations are provided for the hybrid joint based on the proposed model. The use of energy framework enables the model to be extended for fastened joints with complex geometries while not involving any empirical relations. Also, the generic nature of the model can aid in the modeling of various joint configurations, such as multi-bolted and hybrid-multi-bolted joint configurations.
{"title":"Modeling of CFRP hybrid lap joints via energy-based 2D framework","authors":"Rashmiranjan Mohapatra, V. Narayanamurthy, M. Ramji, Sai Sidhardh","doi":"10.1016/j.ijmecsci.2025.109986","DOIUrl":"https://doi.org/10.1016/j.ijmecsci.2025.109986","url":null,"abstract":"This paper presents an energy-based approach to develop a spring-based (semi-analytical) reduced-order model for the mechanical behavior (stiffness, load carrying capacity) of a hybrid (bonded/bolted) single-lap joint with carbon fiber-reinforced polymer (CFRP) laminates when subjected to tensile load. More clearly, the hybrid joint is modeled as an appropriate combination of springs, where their stiffnesses are determined with a deformation energy framework. The proposed model can predict the different failure modes in the hybrid joint with greater accuracy, starting with the disbond of the adhesive layer, followed by damage in CFRP laminates due to the bearing load via bolt, on subsequent loading. In this study, three CFRP ply orientations are considered, i.e., quasi-isotropic (<mml:math altimg=\"si1.svg\" display=\"inline\"><mml:msub><mml:mrow><mml:mrow><mml:mo>[</mml:mo><mml:mn>0</mml:mn><mml:mspace width=\"1em\"></mml:mspace><mml:mn>45</mml:mn><mml:mspace width=\"1em\"></mml:mspace><mml:mn>90</mml:mn><mml:mspace width=\"1em\"></mml:mspace><mml:mo>−</mml:mo><mml:mn>45</mml:mn><mml:mo>]</mml:mo></mml:mrow></mml:mrow><mml:mrow><mml:mi>s</mml:mi></mml:mrow></mml:msub></mml:math>), uni-directional (<mml:math altimg=\"si2.svg\" display=\"inline\"><mml:msub><mml:mrow><mml:mrow><mml:mo>[</mml:mo><mml:mn>0</mml:mn><mml:mo>]</mml:mo></mml:mrow></mml:mrow><mml:mrow><mml:mn>8</mml:mn></mml:mrow></mml:msub></mml:math>), and cross-ply (<mml:math altimg=\"si3.svg\" display=\"inline\"><mml:msub><mml:mrow><mml:mrow><mml:mo>[</mml:mo><mml:mn>0</mml:mn><mml:mspace width=\"1em\"></mml:mspace><mml:mn>90</mml:mn><mml:mo>]</mml:mo></mml:mrow></mml:mrow><mml:mrow><mml:mn>2</mml:mn><mml:mi>s</mml:mi></mml:mrow></mml:msub></mml:math>). The damage modes in the adhesive are modeled using a bilinear cohesive law, and those in CFRP laminates are modeled using Hashin’s damage initiation criteria. A linear degradation law is used to determine the degraded material properties of the CFRP laminate. The individual spring stiffnesses are solved by a developed 2D FE solver. The proposed framework is validated with commercial 3D FEA and experimental studies. Finally, certain design recommendations are provided for the hybrid joint based on the proposed model. The use of energy framework enables the model to be extended for fastened joints with complex geometries while not involving any empirical relations. Also, the generic nature of the model can aid in the modeling of various joint configurations, such as multi-bolted and hybrid-multi-bolted joint configurations.","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"38 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143049779","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}
Understanding the deformation behaviour of refractory high-entropy alloy (rHEA) at elevated temperatures are crucial due to their potential for high-temperature applications. In this study, molecular dynamics simulations were employed using a highly accurate machine learning- based forcefield to investigate the deformation behaviour of MoNbTaW rHEA under uniaxial tensile and compressive loading. Additionally, the dependency of deformation behaviour on the applied strain rates (5e8, 1e9, 5e9 and 1e10 s−1) and temperatures (300, 800, 1000 and 1200 K) was investigated. The yield strength of MoNbTaW rHEA increased by two-fold during compressive loading when compared to tensile loading. During tensile deformation, the BCC-FCC-other atom transition resulted in the formation of stripe-like twinning along the {112} plane. On the contrary, during compressive loading, BCC directly transitioned into other atoms, forming twinning that later acted as the nucleation sites for dislocations. These findings further demonstrate that the deformation mechanism during tensile loading is governed by the twinning mechanism, whereas during compressive loading, dislocation-induced plasticity plays a vital role.
{"title":"Exploring deformation mechanisms in a refractory high entropy alloy (MoNbTaW)","authors":"T.L. Dora, Sandeep Kumar Singh, Radha Raman Mishra, He Yu, Nitin Kishore Rawat, Akarsh Verma","doi":"10.1016/j.ijmecsci.2025.110000","DOIUrl":"https://doi.org/10.1016/j.ijmecsci.2025.110000","url":null,"abstract":"Understanding the deformation behaviour of refractory high-entropy alloy (rHEA) at elevated temperatures are crucial due to their potential for high-temperature applications. In this study, molecular dynamics simulations were employed using a highly accurate machine learning- based forcefield to investigate the deformation behaviour of MoNbTaW rHEA under uniaxial tensile and compressive loading. Additionally, the dependency of deformation behaviour on the applied strain rates (5e8, 1e9, 5e9 and 1e10 <ce:italic>s</ce:italic><ce:sup loc=\"post\">−1</ce:sup>) and temperatures (300, 800, 1000 and 1200 K) was investigated. The yield strength of MoNbTaW rHEA increased by two-fold during compressive loading when compared to tensile loading. During tensile deformation, the BCC-FCC-other atom transition resulted in the formation of stripe-like twinning along the {112} plane. On the contrary, during compressive loading, BCC directly transitioned into other atoms, forming twinning that later acted as the nucleation sites for dislocations. These findings further demonstrate that the deformation mechanism during tensile loading is governed by the twinning mechanism, whereas during compressive loading, dislocation-induced plasticity plays a vital role.","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"48 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143049841","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}
Fundamental frequency vibrations generated by aero-engines can propagate through joint structures to the airframe, potentially causing significant damage to precision instruments and electronic equipment. This paper innovatively integrates the spiral resonant system (elastic wave manipulation capability) into the Hierarchical Diamond Honeycomb with Variable wall Thickness (HDH-VT) structure (lightweight and high-strength mechanical properties), designing a Locally Resonant Metamaterials - Bolted Joints (LRMs-BJ) to suppress the transmission of harmful vibrations from aero-engines to the airframe. First, an equivalent model of the spiral resonant system is developed, with a detailed analysis of the vibration reduction mechanism of the flexural wave bandgap and its tuning capabilities. Second, the vibration reduction characteristics of LRMs-BJs are investigated through finite element simulations and experiments, and the effects of various joint conditions on the vibration reduction frequency band of LRMs-BJs are analyzed. The results demonstrate that the spiral resonant system can produce bandgaps within the target frequency range, and modifying the structural parameters of the spiral elastic beam enables flexible low-frequency tuning of the bandgap. The LRMs-BJ exhibits significant vibration control within the vibration reduction frequency range. The effects of lap length, bolt arrangement direction, and preload on the position and width of the vibration reduction band are minimal, closely aligning with the bandgap of the spiral resonant system unit cell. The proposed LRMs-BJ is a multifunctional integration of metamaterials and honeycomb structures, broadening the application potential of metamaterials in vibration reduction for bolted joints.
{"title":"Vibration control in bolted joints with locally resonant metamaterials","authors":"Min-Min Shen, Ji-Hou Yang, Dong-Shuo Yang, Xiao-Dong Yang, Ying-Jing Qian","doi":"10.1016/j.ijmecsci.2025.109999","DOIUrl":"https://doi.org/10.1016/j.ijmecsci.2025.109999","url":null,"abstract":"Fundamental frequency vibrations generated by aero-engines can propagate through joint structures to the airframe, potentially causing significant damage to precision instruments and electronic equipment. This paper innovatively integrates the spiral resonant system (elastic wave manipulation capability) into the Hierarchical Diamond Honeycomb with Variable wall Thickness (HDH-VT) structure (lightweight and high-strength mechanical properties), designing a Locally Resonant Metamaterials - Bolted Joints (LRMs-BJ) to suppress the transmission of harmful vibrations from aero-engines to the airframe. First, an equivalent model of the spiral resonant system is developed, with a detailed analysis of the vibration reduction mechanism of the flexural wave bandgap and its tuning capabilities. Second, the vibration reduction characteristics of LRMs-BJs are investigated through finite element simulations and experiments, and the effects of various joint conditions on the vibration reduction frequency band of LRMs-BJs are analyzed. The results demonstrate that the spiral resonant system can produce bandgaps within the target frequency range, and modifying the structural parameters of the spiral elastic beam enables flexible low-frequency tuning of the bandgap. The LRMs-BJ exhibits significant vibration control within the vibration reduction frequency range. The effects of lap length, bolt arrangement direction, and preload on the position and width of the vibration reduction band are minimal, closely aligning with the bandgap of the spiral resonant system unit cell. The proposed LRMs-BJ is a multifunctional integration of metamaterials and honeycomb structures, broadening the application potential of metamaterials in vibration reduction for bolted joints.","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"28 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143049842","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}
This study investigates the self-propelled ascent of cylindrical vibrators in granular media under varying force amplitudes, frequencies, particle sizes, and rotational motions. By integrating experimental observations with numerical simulations, critical yielding and shear flow mechanisms are identified, revealing how these processes facilitate vibrator ascent. The results indicate that force amplitude, in conjunction with vibrator rotation, is crucial for overcoming granular confinement. Rotational motion promotes vortex formation and shear banding, thereby reducing resistance and enhancing void-filling beneath the vibrator. A key contribution is the introduction of a characteristic length scale for quantifying dynamic heterogeneity, which enables a predictive framework for determining the critical force required for ascent. Further findings demonstrate that smaller particles, lower frequencies, and higher force amplitudes accelerate ascent, while also uncovering a novel interplay between particle settling and excitation frequency. Finally, a predictive model linking excitation conditions to ascent velocity is proposed, providing a transformative approach for optimizing granular systems in engineering and robotics applications.
{"title":"Unveiling self-propelled ascent in granular media","authors":"Guangyang Hong, Jian Bai, Shibo Wang, Aibing Yu, Jian Li, Shuang Liu","doi":"10.1016/j.ijmecsci.2025.109985","DOIUrl":"https://doi.org/10.1016/j.ijmecsci.2025.109985","url":null,"abstract":"This study investigates the self-propelled ascent of cylindrical vibrators in granular media under varying force amplitudes, frequencies, particle sizes, and rotational motions. By integrating experimental observations with numerical simulations, critical yielding and shear flow mechanisms are identified, revealing how these processes facilitate vibrator ascent. The results indicate that force amplitude, in conjunction with vibrator rotation, is crucial for overcoming granular confinement. Rotational motion promotes vortex formation and shear banding, thereby reducing resistance and enhancing void-filling beneath the vibrator. A key contribution is the introduction of a characteristic length scale for quantifying dynamic heterogeneity, which enables a predictive framework for determining the critical force required for ascent. Further findings demonstrate that smaller particles, lower frequencies, and higher force amplitudes accelerate ascent, while also uncovering a novel interplay between particle settling and excitation frequency. Finally, a predictive model linking excitation conditions to ascent velocity is proposed, providing a transformative approach for optimizing granular systems in engineering and robotics applications.","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"119 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143049843","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 : 2025-01-17DOI: 10.1016/j.ijmecsci.2025.109963
Mahmood Heshmati, S. Kamal Jalali, Nicola M. Pugno
This study introduces a hierarchical design methodology for functional waveguides, utilizing 2D honeycombs with stepwise geometric variations as foundational microstructures, focusing on the tunability of time-domain responses under impact loads. By maintaining constant homogenized density, our approach manipulates stiffness along the wave propagation path. A semi-empirical model, based on curve-fitting to finite element solutions, accurately predicts dynamic responses including wave propagation speed, force transmission to supports, and reflected velocities at the tip. Using Ashby plots, we develop a modular strategy for assembling waveguide bundles – or even bundles of bundles – to meet specific performance criteria, enhancing design efficiency. This framework, ideal for integrating with machine learning and multi-objective optimization, enables tailored designs for applications ranging from impact protection to smart actuation in aerospace, automotive, and biomedical sectors, marking significant advancements in material design for dynamic environments.
{"title":"An innovative hierarchical design of hybrid meta-structures for longitudinal waveguides","authors":"Mahmood Heshmati, S. Kamal Jalali, Nicola M. Pugno","doi":"10.1016/j.ijmecsci.2025.109963","DOIUrl":"https://doi.org/10.1016/j.ijmecsci.2025.109963","url":null,"abstract":"This study introduces a hierarchical design methodology for functional waveguides, utilizing 2D honeycombs with stepwise geometric variations as foundational microstructures, focusing on the tunability of time-domain responses under impact loads. By maintaining constant homogenized density, our approach manipulates stiffness along the wave propagation path. A semi-empirical model, based on curve-fitting to finite element solutions, accurately predicts dynamic responses including wave propagation speed, force transmission to supports, and reflected velocities at the tip. Using Ashby plots, we develop a modular strategy for assembling waveguide bundles – or even bundles of bundles – to meet specific performance criteria, enhancing design efficiency. This framework, ideal for integrating with machine learning and multi-objective optimization, enables tailored designs for applications ranging from impact protection to smart actuation in aerospace, automotive, and biomedical sectors, marking significant advancements in material design for dynamic environments.","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"55 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142990460","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 : 2025-01-16DOI: 10.1016/j.ijmecsci.2025.109979
Luling Wang, Chi Xu, Binpeng Zhu, Jizi Liu, Ningning Liang, Runchang Liu, Yang Cao, Yonghao Zhao
Comprehensive atomic simulations have been conducted to compare the effects of pre-existing dislocation densities on the intermittent plastic behaviors of CoCrNi medium-entropy alloy (MEA) single-crystalline nanopillars with that of pure metal nanopillars. In contrast to pure metal nanopillars that demonstrate prolonged nearly elastic loading and reloading segments, the MEA nanopillars show short loading and reloading segments and high dislocation densities throughout the entire deformation process, suggesting that mechanical annealing is substantially suppressed in MEA nanopillars. The closely spaced junctions between the short-range-order domains and adjacent Ni clusters exert exceptionally strong local Peierls friction forces that not only slow down dislocation slip, but also increase the probability for dislocation entanglement. As a result, high densities of dislocations can be accumulated during the plastic deformation of the MEA nanopillars, leading to suppression of mechanical annealing and transition from exhaustion hardening to strain hardening. This work provides new insights to the plastic deformation of MEA nanopillars that are distinctive from pure metal nanopillars.
{"title":"Short-range ordering suppresses mechanical annealing in CoCrNi alloy nanopillars","authors":"Luling Wang, Chi Xu, Binpeng Zhu, Jizi Liu, Ningning Liang, Runchang Liu, Yang Cao, Yonghao Zhao","doi":"10.1016/j.ijmecsci.2025.109979","DOIUrl":"https://doi.org/10.1016/j.ijmecsci.2025.109979","url":null,"abstract":"Comprehensive atomic simulations have been conducted to compare the effects of pre-existing dislocation densities on the intermittent plastic behaviors of CoCrNi medium-entropy alloy (MEA) single-crystalline nanopillars with that of pure metal nanopillars. In contrast to pure metal nanopillars that demonstrate prolonged nearly elastic loading and reloading segments, the MEA nanopillars show short loading and reloading segments and high dislocation densities throughout the entire deformation process, suggesting that mechanical annealing is substantially suppressed in MEA nanopillars. The closely spaced junctions between the short-range-order domains and adjacent Ni clusters exert exceptionally strong local Peierls friction forces that not only slow down dislocation slip, but also increase the probability for dislocation entanglement. As a result, high densities of dislocations can be accumulated during the plastic deformation of the MEA nanopillars, leading to suppression of mechanical annealing and transition from exhaustion hardening to strain hardening. This work provides new insights to the plastic deformation of MEA nanopillars that are distinctive from pure metal nanopillars.","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"230 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142990461","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 : 2025-01-13DOI: 10.1016/j.ijmecsci.2025.109950
Xiaochao Chen, Runbin Li, Chengcheng Chang, Lin Cheng
In this research, the dynamic features of three-directional functionally graded materials (3DFGMs) rectangular parallelepiped with classic/elastic restraints are investigated based on 3D elastic theory. The general boundary conditions are implemented by introducing artificial displacement springs on the chosen surfaces of rectangular solid. The gradient materials are distributed along the two in-plane and thickness directions of parallelepiped. By setting boundary constraints and geometric parameters, the 3DFGMs rectangular parallelepiped can be evolved into slender beam, thick or thin plate, or even a cuboidal solid. Lagrangian energy functions are formulated for parallelepiped-spring system. The free vibration characters of 3DFGMs rectangular parallelepiped are solved employing the Ritz method in conjunction with the Jacobi polynomials. For transient analysis, the analytical expressions of impulse responses are derived for different types of pulsed excitation. The presented modeling and solution methods are validated by comparing with the results from open literature, finite element analysis and experimental results. Numerical simulations are performed to reveal the effect mechanisms of material gradients, geometrical configuration and boundary restraints on the vibration characters of 3DFGMs parallelepiped. The results demonstrate that dynamic performance of rectangular parallelepiped depends critically on material gradient which may be regarded as regulatory factor to regulate the modal displacement distribution or modal sequence.
{"title":"3D dynamic analysis of elastically restrained multi-directional FGMs rectangular parallelepiped","authors":"Xiaochao Chen, Runbin Li, Chengcheng Chang, Lin Cheng","doi":"10.1016/j.ijmecsci.2025.109950","DOIUrl":"https://doi.org/10.1016/j.ijmecsci.2025.109950","url":null,"abstract":"In this research, the dynamic features of three-directional functionally graded materials (3DFGMs) rectangular parallelepiped with classic/elastic restraints are investigated based on 3D elastic theory. The general boundary conditions are implemented by introducing artificial displacement springs on the chosen surfaces of rectangular solid. The gradient materials are distributed along the two in-plane and thickness directions of parallelepiped. By setting boundary constraints and geometric parameters, the 3DFGMs rectangular parallelepiped can be evolved into slender beam, thick or thin plate, or even a cuboidal solid. Lagrangian energy functions are formulated for parallelepiped-spring system. The free vibration characters of 3DFGMs rectangular parallelepiped are solved employing the Ritz method in conjunction with the Jacobi polynomials. For transient analysis, the analytical expressions of impulse responses are derived for different types of pulsed excitation. The presented modeling and solution methods are validated by comparing with the results from open literature, finite element analysis and experimental results. Numerical simulations are performed to reveal the effect mechanisms of material gradients, geometrical configuration and boundary restraints on the vibration characters of 3DFGMs parallelepiped. The results demonstrate that dynamic performance of rectangular parallelepiped depends critically on material gradient which may be regarded as regulatory factor to regulate the modal displacement distribution or modal sequence.","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"14 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2025-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142990514","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 : 2025-01-09DOI: 10.1016/j.ijmecsci.2025.109941
Liu Rong, Zhong Yifeng, Zhu Yilin, Cao Haiwen, Chen Minfang
The 3D orthogonal accordion core, formed by orthogonal combination of two 2D accordion honeycomb structure, exhibits a multi-directional zero Poisson’s ratio effect and exceptional deformation resistance. To effectively analyze the random-vibration characteristics of the sandwich panel with this type of core, a 2D equivalent Reissner–Mindlin model (2D-ERM) is developed using the variational asymptotic method. The precision of the 2D-ERM in free vibration analysis were validated using free modal vibration test of 3D printed specimens. Its precision in random vibration analysis was confirmed through comparison with 3D Finite Element (FE) simulations, including PSD/RMS responses. Modal analysis indicated that the relative error of 2D-ERM in predicting the first six eigenfrequencies remains below 2%, with the modal clouds demonstrating high reliability. Under base acceleration excitation, the displacement-PSD, velocity-PSD, and acceleration-PSD curves, along with RMS values obtained from 2D-ERM agree well with those from 3D-FEM for various boundary conditions, with the maximum error less than 5%. The length-to-thickness ratio of the extending strut significantly influences the equivalent stiffness, while the re-entrant angle and length-to-thickness ratio of the inclined strut exert the greatest impact on the eigenfrequency and displacement-PSD peak. Compared to SP-3D-XYAS, the equivalent density of SP-3D-OAC is reduced by up to 20%, while still achieving a low displacement-PSD peak. This balance, combined with the absence of coupling effects, makes SP-3D-OAC especially well-suited for applications in precision equipment supports and vibration isolation materials.
{"title":"Free and random-vibration characteristics of sandwich panels featuring orthogonal accordion cores","authors":"Liu Rong, Zhong Yifeng, Zhu Yilin, Cao Haiwen, Chen Minfang","doi":"10.1016/j.ijmecsci.2025.109941","DOIUrl":"https://doi.org/10.1016/j.ijmecsci.2025.109941","url":null,"abstract":"The 3D orthogonal accordion core, formed by orthogonal combination of two 2D accordion honeycomb structure, exhibits a multi-directional zero Poisson’s ratio effect and exceptional deformation resistance. To effectively analyze the random-vibration characteristics of the sandwich panel with this type of core, a 2D equivalent Reissner–Mindlin model (2D-ERM) is developed using the variational asymptotic method. The precision of the 2D-ERM in free vibration analysis were validated using free modal vibration test of 3D printed specimens. Its precision in random vibration analysis was confirmed through comparison with 3D Finite Element (FE) simulations, including PSD/RMS responses. Modal analysis indicated that the relative error of 2D-ERM in predicting the first six eigenfrequencies remains below 2%, with the modal clouds demonstrating high reliability. Under base acceleration excitation, the displacement-PSD, velocity-PSD, and acceleration-PSD curves, along with RMS values obtained from 2D-ERM agree well with those from 3D-FEM for various boundary conditions, with the maximum error less than 5%. The length-to-thickness ratio of the extending strut significantly influences the equivalent stiffness, while the re-entrant angle and length-to-thickness ratio of the inclined strut exert the greatest impact on the eigenfrequency and displacement-PSD peak. Compared to SP-3D-XYAS, the equivalent density of SP-3D-OAC is reduced by up to 20%, while still achieving a low displacement-PSD peak. This balance, combined with the absence of coupling effects, makes SP-3D-OAC especially well-suited for applications in precision equipment supports and vibration isolation materials.","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"26 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142975206","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 : 2025-01-09DOI: 10.1016/j.ijmecsci.2025.109946
Xinyuan Wang, Liqun Tang, Yiping Liu, Zejia Liu, Zhenyu Jiang, Licheng Zhou, Bao Yang
Existing hyperelastic models require a large number of material constants to fully describe the mechanical behavior of compressible polymers, indicating that existing hyperelastic models need to be improved. To address this fundamental problem, we modified the Flory's statistical mechanics model of chain molecular by introducing a generalized multivariate Gaussian distribution of cross-linked units and derived a new Helmholtz free energy expression and macroscopic constitutive equation for polymer networks. The improved Flory's model can not only adaptively describe linear elastic and nonlinear elastic materials, but also unify the form of the constitutive equation whether the material is compressible or not. The experimental results show that the improved Flory's model containing 6 parameters can well describe the mechanical behavior of foam silicone rubber with a volume change of 150 %. Compared with existing models, the improved Flory's model not only does not require the addition of complex volume terms to characterize compressibility, but also has fewer parameters in the constitutive equation. This also shows that the improved Flory's model captures the essence of statistical mechanics of chain molecule well and has better universality.
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