Reliability assessment of complex mechanical system under multi-source uncertain load environment remains a critical challenge in engineering practice. This study proposes a data-physics-driven system-level reliability assessment framework based on cumulative damage-critical damage interference (CDCDI) theory. A system-level cumulative damage-critical damage interference (SL-CDCDI) model is developed to unify the dual probabilistic characterization of cumulative damage and critical damage with failure correlation mechanisms. Physical models ensure mechanistic fidelity in probabilistic damage evolution and failure correlation, while data-driven techniques leverage surrogate models to address high-dimensional loads uncertainty quantification and failure correlation mapping. A 300MW steam turbine rotor case study demonstrates the implementation of the proposed framework, demonstrating its capability to balance mechanistic interpretability and data tractability. Comparative analysis with independent system model (ISM) and hot spot model (HSM) demonstrates that the proposed method effectively avoids the over-conservatism of ISM and the risk underestimation of HSM. Mechanistic analysis indicates that load uncertainty is the root cause of the failure correlation, whose effect is amplified under high load dispersion. This work provides a novel paradigm for system reliability assessment under coupled damage evolution and failure correlation, offering practical guidance for reliability design and maintenance of complex mechanical system under flexible operational demands.
{"title":"Data-physics-driven system reliability assessment via damage interference theory","authors":"Jian-Peng Chen , Li-Yang Xie , Zhi-Yong Hu , Bing-Feng Zhao , Jia-Xin Song , Xing-Yuan Xu , Hang-Hang Gu , Yan-Ding Guo","doi":"10.1016/j.ijmecsci.2026.111369","DOIUrl":"10.1016/j.ijmecsci.2026.111369","url":null,"abstract":"<div><div>Reliability assessment of complex mechanical system under multi-source uncertain load environment remains a critical challenge in engineering practice. This study proposes a data-physics-driven system-level reliability assessment framework based on cumulative damage-critical damage interference (CDCDI) theory. A system-level cumulative damage-critical damage interference (SL-CDCDI) model is developed to unify the dual probabilistic characterization of cumulative damage and critical damage with failure correlation mechanisms. Physical models ensure mechanistic fidelity in probabilistic damage evolution and failure correlation, while data-driven techniques leverage surrogate models to address high-dimensional loads uncertainty quantification and failure correlation mapping. A 300MW steam turbine rotor case study demonstrates the implementation of the proposed framework, demonstrating its capability to balance mechanistic interpretability and data tractability. Comparative analysis with independent system model (ISM) and hot spot model (HSM) demonstrates that the proposed method effectively avoids the over-conservatism of ISM and the risk underestimation of HSM. Mechanistic analysis indicates that load uncertainty is the root cause of the failure correlation, whose effect is amplified under high load dispersion. This work provides a novel paradigm for system reliability assessment under coupled damage evolution and failure correlation, offering practical guidance for reliability design and maintenance of complex mechanical system under flexible operational demands.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"314 ","pages":"Article 111369"},"PeriodicalIF":9.4,"publicationDate":"2026-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146138674","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 : 2026-02-07DOI: 10.1016/j.ijmecsci.2026.111366
Zichuan Li , Jiajie Fan , Guoqi Zhang
<div><div>This study is motivated by a conceptual inconsistency in the physical interpretation of eight-chain hyperelastic theory, which arises from the combined effect of two distinct issues: the use of the marginal projection distribution <span><math><mrow><msub><mrow><mi>p</mi></mrow><mrow><mi>z</mi></mrow></msub><mrow><mo>(</mo><mrow><mo>|</mo><msub><mrow><mi>r</mi></mrow><mrow><mi>z</mi></mrow></msub><mo>|</mo></mrow><mo>)</mo></mrow></mrow></math></span> as a surrogate for the full probability density of end-to-end distance <span><math><mrow><msub><mrow><mi>p</mi></mrow><mrow><mover><mrow><mi>r</mi></mrow><mrow><mo>̄</mo></mrow></mover></mrow></msub><mrow><mo>(</mo><mover><mrow><mi>r</mi></mrow><mrow><mo>̄</mo></mrow></mover><mo>)</mo></mrow></mrow></math></span>, and the subsequent reliance on a root mean square (RMS) approximation step in the micro–macro averaging of chain stretch. We first revisit this probabilistic mismatch by reformulating the probability density function of freely-jointed chains (FJCs) in terms of the squared end-to-end vector <span><math><msup><mrow><mi>r</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span>, thereby restoring consistency on chain-level statistics. Building on this formulation, the micro–macro mapping averaging of chain conformational free energy is constructed directly in terms of <span><math><msup><mrow><mi>r</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span>, leading to a one-step mean-field approximation that avoids RMS averaging. The modified probability transformation is examined by Monte Carlo sampling at the microscopic level. To account for interchain interactions, <span><math><mi>q</mi></math></span>-mean statistical description of micro tube confinement was incorporated, leading to the appearance of the general invariant <span><math><mrow><msub><mrow><mi>I</mi></mrow><mrow><mi>q</mi></mrow></msub><mo>=</mo><msubsup><mrow><mi>λ</mi></mrow><mrow><mn>1</mn></mrow><mrow><mi>q</mi></mrow></msubsup><mo>+</mo><msubsup><mrow><mi>λ</mi></mrow><mrow><mn>2</mn></mrow><mrow><mi>q</mi></mrow></msubsup><mo>+</mo><msubsup><mrow><mi>λ</mi></mrow><mrow><mn>3</mn></mrow><mrow><mi>q</mi></mrow></msubsup></mrow></math></span>. The resulting continuum constitutive model is assessed against multiaxial experimental data for several polymer networks, including vulcanized natural rubber, Entec Enflex S4035A thermoplastic elastomer, Tetra-PEG, and isoprene rubber vulcanizate. Comparisons with three existing hyperelastic strain energy formulations, the extended eight-chain, extended tube models, and the four-parameter ”comprehensive” model, demonstrate comparable phenomenological accuracy of the current model while providing a clearer and more consistent micro–macro physical interpretation of model parameters. A parametric study further illustrates how the dimensionless parameters <span><math><mi>n</mi></math></span> and <span><math><mi>q</mi></math></span> govern the shape of the macroscopic stress–strain re
{"title":"A new physics-motivated constitutive model of hyperelastic polymer networks","authors":"Zichuan Li , Jiajie Fan , Guoqi Zhang","doi":"10.1016/j.ijmecsci.2026.111366","DOIUrl":"10.1016/j.ijmecsci.2026.111366","url":null,"abstract":"<div><div>This study is motivated by a conceptual inconsistency in the physical interpretation of eight-chain hyperelastic theory, which arises from the combined effect of two distinct issues: the use of the marginal projection distribution <span><math><mrow><msub><mrow><mi>p</mi></mrow><mrow><mi>z</mi></mrow></msub><mrow><mo>(</mo><mrow><mo>|</mo><msub><mrow><mi>r</mi></mrow><mrow><mi>z</mi></mrow></msub><mo>|</mo></mrow><mo>)</mo></mrow></mrow></math></span> as a surrogate for the full probability density of end-to-end distance <span><math><mrow><msub><mrow><mi>p</mi></mrow><mrow><mover><mrow><mi>r</mi></mrow><mrow><mo>̄</mo></mrow></mover></mrow></msub><mrow><mo>(</mo><mover><mrow><mi>r</mi></mrow><mrow><mo>̄</mo></mrow></mover><mo>)</mo></mrow></mrow></math></span>, and the subsequent reliance on a root mean square (RMS) approximation step in the micro–macro averaging of chain stretch. We first revisit this probabilistic mismatch by reformulating the probability density function of freely-jointed chains (FJCs) in terms of the squared end-to-end vector <span><math><msup><mrow><mi>r</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span>, thereby restoring consistency on chain-level statistics. Building on this formulation, the micro–macro mapping averaging of chain conformational free energy is constructed directly in terms of <span><math><msup><mrow><mi>r</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span>, leading to a one-step mean-field approximation that avoids RMS averaging. The modified probability transformation is examined by Monte Carlo sampling at the microscopic level. To account for interchain interactions, <span><math><mi>q</mi></math></span>-mean statistical description of micro tube confinement was incorporated, leading to the appearance of the general invariant <span><math><mrow><msub><mrow><mi>I</mi></mrow><mrow><mi>q</mi></mrow></msub><mo>=</mo><msubsup><mrow><mi>λ</mi></mrow><mrow><mn>1</mn></mrow><mrow><mi>q</mi></mrow></msubsup><mo>+</mo><msubsup><mrow><mi>λ</mi></mrow><mrow><mn>2</mn></mrow><mrow><mi>q</mi></mrow></msubsup><mo>+</mo><msubsup><mrow><mi>λ</mi></mrow><mrow><mn>3</mn></mrow><mrow><mi>q</mi></mrow></msubsup></mrow></math></span>. The resulting continuum constitutive model is assessed against multiaxial experimental data for several polymer networks, including vulcanized natural rubber, Entec Enflex S4035A thermoplastic elastomer, Tetra-PEG, and isoprene rubber vulcanizate. Comparisons with three existing hyperelastic strain energy formulations, the extended eight-chain, extended tube models, and the four-parameter ”comprehensive” model, demonstrate comparable phenomenological accuracy of the current model while providing a clearer and more consistent micro–macro physical interpretation of model parameters. A parametric study further illustrates how the dimensionless parameters <span><math><mi>n</mi></math></span> and <span><math><mi>q</mi></math></span> govern the shape of the macroscopic stress–strain re","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"314 ","pages":"Article 111366"},"PeriodicalIF":9.4,"publicationDate":"2026-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146134489","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}
Liquid metal journal bearings (LMJBs), employing liquid metal (LM) as a highly conductive and thermally stable lubricant, are increasingly used in CT tubes to withstand high temperatures and dissipate heat. This work establishes a three-dimensional thermohydrodynamic model of the LMJB, incorporating its distinctive features, including herringbone grooves, extreme operating environment, and thermal input from the CT system. Specifically, it accounts for the groove pumping effect, fluid–solid heat transfer interface, vacuum thermal radiation, and high-temperature input at the end-face. Boundary conditions are assigned according to the local thermal characteristics. An experimental rig was built to validate the model by comparing temperatures at different rotational speeds. The temperature distribution was analyzed, and the effects of bearing parameters and operating conditions were assessed. The results show that the grooves induce fluctuations in the temperature. Groove geometry and bearing structural parameters significantly influence the peak temperature. High-conductivity LM or enhanced convective heat transfer effectively lowers the temperature, with the bush as the primary heat dissipation path. Moreover, the heat input from the end-faces has a decisive influence on the bearing temperature. These findings provide guidance for LMJB design and cooling strategies to ensure reliable operation in high performance CT applications.
{"title":"Thermohydrodynamic analysis of liquid metal journal bearings in CT tubes","authors":"Yujie Wang, Shuai Huang, JiongGuang Wei, Jian Li, Wenjun Li, Kai Feng","doi":"10.1016/j.ijmecsci.2026.111365","DOIUrl":"10.1016/j.ijmecsci.2026.111365","url":null,"abstract":"<div><div>Liquid metal journal bearings (LMJBs), employing liquid metal (LM) as a highly conductive and thermally stable lubricant, are increasingly used in CT tubes to withstand high temperatures and dissipate heat. This work establishes a three-dimensional thermohydrodynamic model of the LMJB, incorporating its distinctive features, including herringbone grooves, extreme operating environment, and thermal input from the CT system. Specifically, it accounts for the groove pumping effect, fluid–solid heat transfer interface, vacuum thermal radiation, and high-temperature input at the end-face. Boundary conditions are assigned according to the local thermal characteristics. An experimental rig was built to validate the model by comparing temperatures at different rotational speeds. The temperature distribution was analyzed, and the effects of bearing parameters and operating conditions were assessed. The results show that the grooves induce fluctuations in the temperature. Groove geometry and bearing structural parameters significantly influence the peak temperature. High-conductivity LM or enhanced convective heat transfer effectively lowers the temperature, with the bush as the primary heat dissipation path. Moreover, the heat input from the end-faces has a decisive influence on the bearing temperature. These findings provide guidance for LMJB design and cooling strategies to ensure reliable operation in high performance CT applications.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"314 ","pages":"Article 111365"},"PeriodicalIF":9.4,"publicationDate":"2026-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146138675","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}
The emerging all-solid-state batteries (ASSBs) hold significant promise for next-generation energy storage, yet their mechanical reliability under dynamic impact loading remains a critical challenge. During service, external dynamic loads with high strain rates can induce excessive crack propagation and catastrophic failure, posing substantial risks to structural integrity and electrochemical performance. This study establishes a multiphysics-coupled framework to investigate the dynamic fracture mechanisms within the composite cathode of ASSBs under impact conditions by integrating chemo-mechanical interactions. The model incorporates a bond-based peridynamic framework for active materials (AM), an interface model couples the electrochemical parameters governing charging processes, and a Johnson–Cook (JC) constitutive model for bond-type interactions in the solid electrolytes (SE) to characterize the strain rate-dependent behavior. We systematically investigate the effects of strain rate-dependent impact loading on fracture propagation modes and electrochemical performance degradation in composite cathode. The findings elucidate the multi-physics failure mechanisms under dynamic loading scenarios, providing critical insights for designing next-generation solid-state batteries with enhanced mechanical integrity and safety.
{"title":"Peridynamic modeling of impact induced electrochemical degradation in all-solid-state batteries","authors":"Zhewen Zhang, Xiaoxun Li, Sheng Qian, Youlin Zhu, Lianfu Qiu, Xiaofei Wang, Qi Tong","doi":"10.1016/j.ijmecsci.2026.111328","DOIUrl":"10.1016/j.ijmecsci.2026.111328","url":null,"abstract":"<div><div>The emerging all-solid-state batteries (ASSBs) hold significant promise for next-generation energy storage, yet their mechanical reliability under dynamic impact loading remains a critical challenge. During service, external dynamic loads with high strain rates can induce excessive crack propagation and catastrophic failure, posing substantial risks to structural integrity and electrochemical performance. This study establishes a multiphysics-coupled framework to investigate the dynamic fracture mechanisms within the composite cathode of ASSBs under impact conditions by integrating chemo-mechanical interactions. The model incorporates a bond-based peridynamic framework for active materials (AM), an interface model couples the electrochemical parameters governing charging processes, and a Johnson–Cook (JC) constitutive model for bond-type interactions in the solid electrolytes (SE) to characterize the strain rate-dependent behavior. We systematically investigate the effects of strain rate-dependent impact loading on fracture propagation modes and electrochemical performance degradation in composite cathode. The findings elucidate the multi-physics failure mechanisms under dynamic loading scenarios, providing critical insights for designing next-generation solid-state batteries with enhanced mechanical integrity and safety.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"314 ","pages":"Article 111328"},"PeriodicalIF":9.4,"publicationDate":"2026-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146138676","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 : 2026-02-06DOI: 10.1016/j.ijmecsci.2026.111360
Changqi Cai , Xin Guo , Hongye Ma , Jiaxi Zhou , Bo Yan
Low-frequency structural vibrations are subject to frequency shifts due to changing environmental conditions. To suppress the structural vibrations, a semi-active quasi-zero-stiffness (QZS) metamaterial beam is designed by integrating the compliant and electromagnetic mechanisms for flexural wave attenuation within tunable low-frequency bandgaps. The compliant mechanism is responsible for the QZS-based low-frequency bandgap, while the electromagnetic mechanism enables the semi-active modulation of bandgap frequency by varying the overall stiffness. A simplified theoretical model is established to derive the dispersion relations of the metamaterial beam. The formation and modulation mechanisms of the low-frequency bandgaps are revealed using the transfer matrix method (TMM) and further validated by the spectral element method (SEM). Dynamic experiments are performed to confirm its bandgap modulation performance at low frequencies. Both experiment and theory demonstrate that the semi-active metamaterial beam can effectively regulate low-frequency bandgaps and suppress flexural wave propagation at desired frequencies with only a low coil current. Therefore, the proposed QZS metamaterials should be a promising solution for suppressing elastic waves with varying frequencies in engineering structures.
{"title":"Tunable low-frequency bandgaps in semi-active quasi-zero-stiffness metamaterial beam","authors":"Changqi Cai , Xin Guo , Hongye Ma , Jiaxi Zhou , Bo Yan","doi":"10.1016/j.ijmecsci.2026.111360","DOIUrl":"10.1016/j.ijmecsci.2026.111360","url":null,"abstract":"<div><div>Low-frequency structural vibrations are subject to frequency shifts due to changing environmental conditions. To suppress the structural vibrations, a semi-active quasi-zero-stiffness (QZS) metamaterial beam is designed by integrating the compliant and electromagnetic mechanisms for flexural wave attenuation within tunable low-frequency bandgaps. The compliant mechanism is responsible for the QZS-based low-frequency bandgap, while the electromagnetic mechanism enables the semi-active modulation of bandgap frequency by varying the overall stiffness. A simplified theoretical model is established to derive the dispersion relations of the metamaterial beam. The formation and modulation mechanisms of the low-frequency bandgaps are revealed using the transfer matrix method (TMM) and further validated by the spectral element method (SEM). Dynamic experiments are performed to confirm its bandgap modulation performance at low frequencies. Both experiment and theory demonstrate that the semi-active metamaterial beam can effectively regulate low-frequency bandgaps and suppress flexural wave propagation at desired frequencies with only a low coil current. Therefore, the proposed QZS metamaterials should be a promising solution for suppressing elastic waves with varying frequencies in engineering structures.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"314 ","pages":"Article 111360"},"PeriodicalIF":9.4,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146134491","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 : 2026-02-06DOI: 10.1016/j.ijmecsci.2026.111364
J.C. Cheng , T. Yang , L. Wang , J.Y. Hua , J.Y. Huang , L.X. He , W. Feng , Y. Cai , Q.Y. Wang , S.N. Luo
High-speed ballistic impacts are carried out with high-speed photography on 2-mm thick CrCoNi alloy plates with 5-mm spherical stainless steel projectiles within the impact velocity range of 5141436 m s−1. Post-impact samples are characterized by optical imaging, microhardness, electron backscatter diffraction and transmission electron microscopy. With increasing impact velocity, bulging, complete plugging and fragmentation occur sequentially. The ballistic limit velocity for the investigated projectile–target combination is 530 m s−1, significantly higher than that of CrMnFeCoNi plate (495 m s−1). The area of the crater/bullet hole exhibits a linear relationship with projectile kinetic energy loss. Dislocations, stacking faults, Lomer–Cottrell locks, deformation bands and various twin variants, contribute to enhanced strain-hardening capacity and penetration resistance. The bending of the target plate induced by low-velocity impact leads to additional plastic deformation and higher microhardness. Based on the Johnson–Cook constitutive model and the damage criterion, the finite element simulations effectively reproduce the ballistic impact experiments. Molecular dynamics simulations reproduce microstructural evolution at the atomic scale. The and twin variants are simultaneously activated, because of the equivalence of the twin planes and twin directions of these two variants relative to the impact direction. This study presents the high-velocity perforation failure behavior of this medium-entropy alloy, elucidates the deformation and damage mechanisms, and provide valuable insights for its safety assessment and material/structural optimization design in extreme loading environments.
在514 ~ 1436 m s−1的冲击速度范围内，采用高速摄影技术对5mm球形不锈钢弹丸在2mm厚CrCoNi合金板上进行高速弹道冲击。通过光学成像、显微硬度、电子背散射衍射和透射电镜对撞击后样品进行表征。随着冲击速度的增加，胀形、完全堵塞和破碎依次发生。弹靶组合的弹道极限速度为530 m s−1，显著高于crmnnfeconi板的极限速度（495 m s−1）。弹坑/弹孔面积与弹丸动能损失呈线性关系。位错、层错、lomo - cottrell锁、变形带和各种孪晶变体有助于增强应变硬化能力和抗渗透能力。低速冲击引起的靶板弯曲导致额外的塑性变形和更高的显微硬度。基于Johnson-Cook本构模型和损伤准则的有限元模拟能够有效地再现弹道冲击实验。分子动力学模拟在原子尺度上再现微观结构的演变。111112和111112双生变体同时被激活，因为这两个变体的双生平面和双生方向相对于1’10撞击方向是等价的。本研究展示了这种中熵合金的高速穿孔破坏行为，阐明了其变形和损伤机制，为其在极端载荷环境下的安全性评估和材料/结构优化设计提供了有价值的见解。
{"title":"High-velocity perforation of medium-entropy CrCoNi thin plates by spherical projectiles","authors":"J.C. Cheng , T. Yang , L. Wang , J.Y. Hua , J.Y. Huang , L.X. He , W. Feng , Y. Cai , Q.Y. Wang , S.N. Luo","doi":"10.1016/j.ijmecsci.2026.111364","DOIUrl":"10.1016/j.ijmecsci.2026.111364","url":null,"abstract":"<div><div>High-speed ballistic impacts are carried out with high-speed photography on 2-mm thick CrCoNi alloy plates with 5-mm spherical stainless steel projectiles within the impact velocity range of 514<span><math><mo>−</mo></math></span>1436 m<!--> <!-->s<sup>−1</sup>. Post-impact samples are characterized by optical imaging, microhardness, electron backscatter diffraction and transmission electron microscopy. With increasing impact velocity, bulging, complete plugging and fragmentation occur sequentially. The ballistic limit velocity for the investigated projectile–target combination is 530 m<!--> <!-->s<sup>−1</sup>, significantly higher than that of CrMnFeCoNi plate (495 m<!--> <!-->s<sup>−1</sup>). The area of the crater/bullet hole exhibits a linear relationship with projectile kinetic energy loss. Dislocations, stacking faults, Lomer–Cottrell locks, deformation bands and various twin variants, contribute to enhanced strain-hardening capacity and penetration resistance. The bending of the target plate induced by low-velocity impact leads to additional plastic deformation and higher microhardness. Based on the Johnson–Cook constitutive model and the damage criterion, the finite element simulations effectively reproduce the ballistic impact experiments. Molecular dynamics simulations reproduce microstructural evolution at the atomic scale. The <span><math><mrow><mfenced><mrow><mn>111</mn></mrow></mfenced><mfenced><mrow><mn>11</mn><mover><mrow><mn>2</mn></mrow><mrow><mo>̄</mo></mrow></mover></mrow></mfenced></mrow></math></span> and <span><math><mrow><mfenced><mrow><mn>11</mn><mover><mrow><mn>1</mn></mrow><mrow><mo>̄</mo></mrow></mover></mrow></mfenced><mfenced><mrow><mn>112</mn></mrow></mfenced></mrow></math></span> twin variants are simultaneously activated, because of the equivalence of the twin planes and twin directions of these two variants relative to the <span><math><mfenced><mrow><mover><mrow><mn>1</mn></mrow><mrow><mo>̄</mo></mrow></mover><mn>10</mn></mrow></mfenced></math></span> impact direction. This study presents the high-velocity perforation failure behavior of this medium-entropy alloy, elucidates the deformation and damage mechanisms, and provide valuable insights for its safety assessment and material/structural optimization design in extreme loading environments.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"314 ","pages":"Article 111364"},"PeriodicalIF":9.4,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146134497","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 : 2026-02-06DOI: 10.1016/j.ijmecsci.2026.111361
Chang-Yeon Gu , Min Hyeok Choi , Min Sang Ju , Dohun Kim , Sung Woo Ma , Tae-Ik Lee , Taek-Soo Kim
Warpage control of carrier wafers is a critical challenge in advanced semiconductor packaging processes, as wafer-level deformation impacts not only subsequent processing steps but also the quality of the final chip package, which typically requires high-precision assembly. Therefore, understanding the wafer bending behavior is necessary to accurately predict and control the warpage. In this study, nonlinear warpage models were first developed for carrier wafers controlled by dielectric layer deposition to suggest an extended Stoney formula that accounts for elastic anisotropy, including material properties and curvature, and large deformation behavior. Finite element analysis (FEA) simulations were conducted to investigate warpage behavior according to dielectric film thickness and residual stress. Nonlinear warpage models were established for different thickness ratios of film and substrate systems, which were then integrated into a single master curve that enables rapid estimation of the required dielectric layer thickness or residual stress for effective warpage control. Quantitative analysis revealed that incorporating both anisotropic Young’s modulus and anisotropic curvature of carrier wafers improves warpage prediction accuracy by up to 45.1 % for the onset of nonlinearity and 15.2 % for the resulting nonlinearity magnitude. Furthermore, the universal master curve reveals that nonlinear warpage behavior emerges when the edge deflection-to-wafer thickness ratio exceeds 0.85. Based on this framework, a pre-bow treatment strategy is proposed and validated through numerical analysis, demonstrating up to a 97.9 % reduction in warpage. The presented methodology offers a systematic and physically grounded approach to warpage control, enabling improved process reliability while reducing development time and cost in advanced semiconductor packaging.
{"title":"Nonlinear warpage modeling of dielectric-controlled carrier wafers","authors":"Chang-Yeon Gu , Min Hyeok Choi , Min Sang Ju , Dohun Kim , Sung Woo Ma , Tae-Ik Lee , Taek-Soo Kim","doi":"10.1016/j.ijmecsci.2026.111361","DOIUrl":"10.1016/j.ijmecsci.2026.111361","url":null,"abstract":"<div><div>Warpage control of carrier wafers is a critical challenge in advanced semiconductor packaging processes, as wafer-level deformation impacts not only subsequent processing steps but also the quality of the final chip package, which typically requires high-precision assembly. Therefore, understanding the wafer bending behavior is necessary to accurately predict and control the warpage. In this study, nonlinear warpage models were first developed for carrier wafers controlled by dielectric layer deposition to suggest an extended Stoney formula that accounts for elastic anisotropy, including material properties and curvature, and large deformation behavior. Finite element analysis (FEA) simulations were conducted to investigate warpage behavior according to dielectric film thickness and residual stress. Nonlinear warpage models were established for different thickness ratios of film and substrate systems, which were then integrated into a single master curve that enables rapid estimation of the required dielectric layer thickness or residual stress for effective warpage control. Quantitative analysis revealed that incorporating both anisotropic Young’s modulus and anisotropic curvature of carrier wafers improves warpage prediction accuracy by up to 45.1 % for the onset of nonlinearity and 15.2 % for the resulting nonlinearity magnitude. Furthermore, the universal master curve reveals that nonlinear warpage behavior emerges when the edge deflection-to-wafer thickness ratio exceeds 0.85. Based on this framework, a pre-bow treatment strategy is proposed and validated through numerical analysis, demonstrating up to a 97.9 % reduction in warpage. The presented methodology offers a systematic and physically grounded approach to warpage control, enabling improved process reliability while reducing development time and cost in advanced semiconductor packaging.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"314 ","pages":"Article 111361"},"PeriodicalIF":9.4,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146134490","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 : 2026-02-06DOI: 10.1016/j.ijmecsci.2026.111358
Jiao Wang , Nan Gao , Weiqiu Chen
Topologically protected interface states (ISs) exhibit inherent robustness, maintaining stable wave propagation under local perturbations. While this robustness guarantees stability, it also poses challenges for active control. Here, we propose a design strategy that integrates global configuration tuning with local interface reconfiguration to manipulate ISs and higher-order topological corner states (HOTCSs) in two-dimensional (2D) acoustic metamaterials. Global modulation reconfigures the entire structure to adjust interface bandwidths and control the presence of HOTCSs. In contrast, localized reconfiguration modifies only the interface region while preserving the global structure, enabling precise tuning of interface-state frequencies and selective excitation or suppression of corner states (CSs). Incorporating localized modulation regions into finite structures establishes a versatile framework for wave control, including arbitrary output positioning and asymmetric transmission at fixed frequencies under opposite excitations. Finite-element simulations (FES) validate the effectiveness of this approach, demonstrating its potential for highly flexible wave manipulation in topological acoustic systems. These results establish a general design framework for tunable and reconfigurable acoustic systems with controllable ISs and CSs.
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Pub Date : 2026-02-06DOI: 10.1016/j.ijmecsci.2026.111337
Zhiqiang Zhao , Heyun Bao , Zouhao Song , Fengxia Lu , Shanshan Liu
The pressure–temperature–time history is crucial for operating precision and service life of a wet clutch under high energy levels. However, there still lacks a simple and accurate model to predict the contact heat transfer at the sliding friction interface during the rotation-axial engagement process. In this paper, a transient thermal analysis of a multi-disc wet clutch is performed to capture the heat transfer behaviour of a sliding friction pair during the entire engagement cycle. The thermal conditions of the clutch are formulated by the dynamic model of a multi-body system considering the coupled effects of hydrodynamic lubrication, asperity contact, squeeze motion and sliding motion. The temperature characteristics of the clutch discs are investigated in detail by utilizing the thermal contact conductance under squeeze-sliding conditions. The peak temperatures of separator disc and friction lining are influenced by various applied pressures, material properties and load torques. As the applied pressure increases from 1.0 MPa to 1.6 MPa, the peak temperatures of the separator disc and friction lining are predicted to increase by 35.6% and 40.3%, respectively. When the load torque increases from 0 N m to 300 N m, the highest temperature of separator disc and friction lining increase by 16.3% and 15.8%, respectively. The developed thermal model could be a practicable toolkit for forecasting the temperature of a wet clutch under complex operating conditions.
压力-温度-时间历史对高能量水平下湿式离合器的操作精度和使用寿命至关重要。然而，目前还缺乏一种简单准确的模型来预测旋转-轴向接触过程中滑动摩擦界面处的接触换热。本文对多片湿离合器进行了瞬态热分析，以捕捉滑动摩擦副在整个接合周期中的传热行为。考虑流体动力润滑、粗糙接触、挤压运动和滑动运动的耦合效应，采用多体系统动力学模型建立了离合器的热工况。利用接触热导对离合器盘在挤压滑动条件下的温度特性进行了详细的研究。分离盘和摩擦衬的峰值温度受各种施加压力、材料性能和载荷扭矩的影响。当施加压力从1.0 MPa增加到1.6 MPa时，分离盘和摩擦衬的峰值温度分别升高35.6%和40.3%。负载转矩从0 N m增加到300 N m时，分离盘和摩擦衬的最高温度分别提高了16.3%和15.8%。所建立的热模型可作为预测复杂工况下湿式离合器温度的实用工具。
{"title":"Transient thermal behaviour of a wet clutch using multi-body dynamics","authors":"Zhiqiang Zhao , Heyun Bao , Zouhao Song , Fengxia Lu , Shanshan Liu","doi":"10.1016/j.ijmecsci.2026.111337","DOIUrl":"10.1016/j.ijmecsci.2026.111337","url":null,"abstract":"<div><div>The pressure–temperature–time history is crucial for operating precision and service life of a wet clutch under high energy levels. However, there still lacks a simple and accurate model to predict the contact heat transfer at the sliding friction interface during the rotation-axial engagement process. In this paper, a transient thermal analysis of a multi-disc wet clutch is performed to capture the heat transfer behaviour of a sliding friction pair during the entire engagement cycle. The thermal conditions of the clutch are formulated by the dynamic model of a multi-body system considering the coupled effects of hydrodynamic lubrication, asperity contact, squeeze motion and sliding motion. The temperature characteristics of the clutch discs are investigated in detail by utilizing the thermal contact conductance under squeeze-sliding conditions. The peak temperatures of separator disc and friction lining are influenced by various applied pressures, material properties and load torques. As the applied pressure increases from 1.0 MPa to 1.6 MPa, the peak temperatures of the separator disc and friction lining are predicted to increase by 35.6% and 40.3%, respectively. When the load torque increases from 0 N m to 300 N m, the highest temperature of separator disc and friction lining increase by 16.3% and 15.8%, respectively. The developed thermal model could be a practicable toolkit for forecasting the temperature of a wet clutch under complex operating conditions.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"314 ","pages":"Article 111337"},"PeriodicalIF":9.4,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146134500","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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