Pub Date : 2025-09-29DOI: 10.1016/j.eml.2025.102410
Jianxiong Li , Yuan Yao , Mostafa Hassani
GRCop-42 is a Cu-based alloy strengthened primarily through precipitation hardening by a single Cr2Nb phase. While its deformation mechanisms under quasi-static conditions have been extensively studied, the behavior of these precipitates under extreme strain rates remains poorly understood. In this study, we investigate the high-rate response of GRCop-42 powder using laser-induced microparticle impact testing (LIPIT), where individual alloy particles are impacted onto a pure Cu substrate at velocities ranging from 100 to 600 m/s. We observe a transition from rebound to impact-induced bonding at ∼490 ± 11 m/s. Cross-sectional microstructural analysis of bonded particles reveals that, although high strain rate impact does not lead to significant precipitate fracture or coarsening, the precipitates undergo shape changes. At higher velocities, the Cr2Nb precipitates exhibit increased aspect ratios, particularly near particle edges. This oblate deformation at the precipitate scale is attributed to localized temperature rise from adiabatic heating, driven by extreme plastic deformation. The effect is more pronounced at higher velocities and is spatially concentrated near the periphery of the particle–substrate interface.
{"title":"Precipitate response in GRCop-42 metallic microparticles under extreme impact conditions","authors":"Jianxiong Li , Yuan Yao , Mostafa Hassani","doi":"10.1016/j.eml.2025.102410","DOIUrl":"10.1016/j.eml.2025.102410","url":null,"abstract":"<div><div>GRCop-42 is a Cu-based alloy strengthened primarily through precipitation hardening by a single Cr<sub>2</sub>Nb phase. While its deformation mechanisms under quasi-static conditions have been extensively studied, the behavior of these precipitates under extreme strain rates remains poorly understood. In this study, we investigate the high-rate response of GRCop-42 powder using laser-induced microparticle impact testing (LIPIT), where individual alloy particles are impacted onto a pure Cu substrate at velocities ranging from 100 to 600 m/s. We observe a transition from rebound to impact-induced bonding at ∼490 ± 11 m/s. Cross-sectional microstructural analysis of bonded particles reveals that, although high strain rate impact does not lead to significant precipitate fracture or coarsening, the precipitates undergo shape changes. At higher velocities, the Cr<sub>2</sub>Nb precipitates exhibit increased aspect ratios, particularly near particle edges. This oblate deformation at the precipitate scale is attributed to localized temperature rise from adiabatic heating, driven by extreme plastic deformation. The effect is more pronounced at higher velocities and is spatially concentrated near the periphery of the particle–substrate interface.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"80 ","pages":"Article 102410"},"PeriodicalIF":4.5,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145227245","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}
Pub Date : 2025-09-25DOI: 10.1016/j.eml.2025.102407
Colin M. Meulblok , Hadrien Bense , M. Caelen , Martin van Hecke
The hysteretic snapping under transverse forcing of a compressed, buckled beam is fundamental for many devices and mechanical metamaterials. For a single-tip transverse pusher, an important limitation is that snapping requires the pusher to cross the longitudinal axis of the beam. Here, we show that dual-tip pushers allow early-onset snapping, where the beam snaps before the pusher reaches the longitudinal axis. As a consequence, we show that when a buckled beam under increased compression comes in contact with a dual-tip pusher, it can snap to the opposite direction — this is impossible with a single-tip pusher. Additionally, we reveal a novel two-step snapping regime, in which the beam sequentially loses contact with the two tips of the dual-tip pusher. To characterize this class of snapping instabilities, we employ a systematic modal expansion of the beam shape. This expansion allows us to capture and analyze the transition from one-step to two-step snapping geometrically. Finally we demonstrate how to maximize the distance between the pusher and the beam’s longitudinal axis at the moment of snapping. Together, our work opens up a new avenue for quantitatively and qualitatively controlling and modifying the snapping of buckled beams, with potential applications in mechanical sensors, actuators, and metamaterials.
{"title":"Early onset of snapping of slender beams under transverse forcing","authors":"Colin M. Meulblok , Hadrien Bense , M. Caelen , Martin van Hecke","doi":"10.1016/j.eml.2025.102407","DOIUrl":"10.1016/j.eml.2025.102407","url":null,"abstract":"<div><div>The hysteretic snapping under transverse forcing of a compressed, buckled beam is fundamental for many devices and mechanical metamaterials. For a single-tip transverse pusher, an important limitation is that snapping requires the pusher to cross the longitudinal axis of the beam. Here, we show that dual-tip pushers allow <em>early-onset snapping</em>, where the beam snaps before the pusher reaches the longitudinal axis. As a consequence, we show that when a buckled beam under increased compression comes in contact with a dual-tip pusher, it can snap to the opposite direction — this is impossible with a single-tip pusher. Additionally, we reveal a novel <em>two-step snapping</em> regime, in which the beam sequentially loses contact with the two tips of the dual-tip pusher. To characterize this class of snapping instabilities, we employ a systematic modal expansion of the beam shape. This expansion allows us to capture and analyze the transition from one-step to two-step snapping geometrically. Finally we demonstrate how to maximize the distance between the pusher and the beam’s longitudinal axis at the moment of snapping. Together, our work opens up a new avenue for quantitatively and qualitatively controlling and modifying the snapping of buckled beams, with potential applications in mechanical sensors, actuators, and metamaterials.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"80 ","pages":"Article 102407"},"PeriodicalIF":4.5,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145158573","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}
Pub Date : 2025-09-23DOI: 10.1016/j.eml.2025.102408
Xi Chen , Xiaoling Jin , Yong Wang , Zhilong Huang
Tracing back the past and predicting the future are of equal importance, while compared to the prediction, the backtracking is far from receiving the attention it deserves. With the explosive advances of the diffusion models, backtracking has undergone a complete renaissance, especially for stochastic systems. This work addresses this issue, tracing back transient information from near-stationary random data. Different from the diffusion models, we aim for statistical information but not sample information, and we only need near-stationary sample segments for identification, but not a large number of full-time samples for learning. The core idea of this data-driven method is: embedding Fokker-Planck equation (as a priori physical knowledge), which portrays the evolution of probability density of state, and then identifying and solving it to trace back the transient probability density. The efficacy of this method is demonstrated by three typical examples, namely, a one-dimensional linear system, a two-dimensional linear system, and the van der Pol system.
回顾过去和预测未来同样重要，但与预测相比，回溯远远没有得到应有的重视。随着扩散模型的爆炸式发展，回溯已经经历了一个完整的复兴，特别是对于随机系统。这项工作解决了这个问题，从接近平稳的随机数据中追溯瞬态信息。与扩散模型不同的是，我们的目标是统计信息而不是样本信息，我们只需要近平稳的样本段进行识别，而不需要大量的全职样本进行学习。这种数据驱动方法的核心思想是：嵌入描述状态概率密度演变的Fokker-Planck方程（作为先验的物理知识），然后对其进行识别和求解，追溯瞬时概率密度。通过一维线性系统、二维线性系统和van der Pol系统三个典型实例证明了该方法的有效性。
{"title":"Tracing back transient information from near-stationary random data","authors":"Xi Chen , Xiaoling Jin , Yong Wang , Zhilong Huang","doi":"10.1016/j.eml.2025.102408","DOIUrl":"10.1016/j.eml.2025.102408","url":null,"abstract":"<div><div>Tracing back the past and predicting the future are of equal importance, while compared to the prediction, the backtracking is far from receiving the attention it deserves. With the explosive advances of the diffusion models, backtracking has undergone a complete renaissance, especially for stochastic systems. This work addresses this issue, tracing back transient information from near-stationary random data. Different from the diffusion models, we aim for statistical information but not sample information, and we only need near-stationary sample segments for identification, but not a large number of full-time samples for learning. The core idea of this data-driven method is: embedding Fokker-Planck equation (as a priori physical knowledge), which portrays the evolution of probability density of state, and then identifying and solving it to trace back the transient probability density. The efficacy of this method is demonstrated by three typical examples, namely, a one-dimensional linear system, a two-dimensional linear system, and the van der Pol system.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"80 ","pages":"Article 102408"},"PeriodicalIF":4.5,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145158574","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}
Pub Date : 2025-09-23DOI: 10.1016/j.eml.2025.102409
Zhaoxin Zhang , Weifeng Zou , Yukai Zhao , Shuze Zhu , Tiefeng Li
Polymer electrolytes in solid-state batteries are critical for applications demanding mechanical flexibility and tolerance. Recent research progress has underscored the potential significance of employing solid electrolytes in extreme environments, such as the high hydrostatic pressure encountered during deep-sea exploration. Consequently, understanding how extreme hydrostatic pressure affects ion diffusion in polymer electrolytes is of substantial importance. In this work, large-scale molecular dynamics simulations are utilized to investigate the diffusion of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) in a representative polymer electrolyte, specifically poly(ethylene oxide) (PEO). We reveal a previously unreported mechanism associated with the emergence of a glass-transition pressure, above which the polymer matrix exhibits glass-like characteristics. The transport behavior of Li⁺ ions shows a distinct contrast below and beyond this critical pressure. Through theoretical scaling analysis, we show that ionic diffusivity is proportional to material volume, and is therefore governed by this same phase-transition pressure, which rationalizes our simulation results. This work provides potential guidance for understanding and designing polymer electrolytes with tolerance to extreme pressures.
{"title":"Effect of extreme hydrostatic pressure on ion diffusion in polymer electrolytes: Emergence of glass-transition pressure","authors":"Zhaoxin Zhang , Weifeng Zou , Yukai Zhao , Shuze Zhu , Tiefeng Li","doi":"10.1016/j.eml.2025.102409","DOIUrl":"10.1016/j.eml.2025.102409","url":null,"abstract":"<div><div>Polymer electrolytes in solid-state batteries are critical for applications demanding mechanical flexibility and tolerance. Recent research progress has underscored the potential significance of employing solid electrolytes in extreme environments, such as the high hydrostatic pressure encountered during deep-sea exploration. Consequently, understanding how extreme hydrostatic pressure affects ion diffusion in polymer electrolytes is of substantial importance. In this work, large-scale molecular dynamics simulations are utilized to investigate the diffusion of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) in a representative polymer electrolyte, specifically poly(ethylene oxide) (PEO). We reveal a previously unreported mechanism associated with the emergence of a glass-transition pressure, above which the polymer matrix exhibits glass-like characteristics. The transport behavior of Li⁺ ions shows a distinct contrast below and beyond this critical pressure. Through theoretical scaling analysis, we show that ionic diffusivity is proportional to material volume, and is therefore governed by this same phase-transition pressure, which rationalizes our simulation results. This work provides potential guidance for understanding and designing polymer electrolytes with tolerance to extreme pressures.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"80 ","pages":"Article 102409"},"PeriodicalIF":4.5,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145158572","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}
Pub Date : 2025-09-20DOI: 10.1016/j.eml.2025.102406
Aarosh Dahal, Aditya Kumar
Thin layers of elastomers bonded to two rigid plates demonstrate unusual failure response. Historically, it has been believed that strongly-bonded layers fail by two distinct mechanisms: (i) internal/external penny-shaped crack nucleation and propagation, and (ii) cavitation, that is, cavity growth leading to fibrillation and then failure. However, recent work has demonstrated that cavitation itself is predominantly a fracture process. While the equations describing cavitation from a macroscopic or top-down view are now known and validated with experiments, several aspects of the cavitation crack growth need to be better understood. Notably, cavitation often involves through-thickness crack growth parallel to the loading direction, raising questions about when it initiates instead of the more typical penny-shaped cracks perpendicular to the load. Understanding and controlling the two vertical and horizontal crack growth is key to developing tougher soft films and adhesives. The purpose of this Letter is to provide an explanation for the load-parallel crack growth through a comprehensive numerical analysis and highlight the role of various material and geometrical parameters.
{"title":"On failure mechanisms and load-parallel cracking in confined elastomeric layers","authors":"Aarosh Dahal, Aditya Kumar","doi":"10.1016/j.eml.2025.102406","DOIUrl":"10.1016/j.eml.2025.102406","url":null,"abstract":"<div><div>Thin layers of elastomers bonded to two rigid plates demonstrate unusual failure response. Historically, it has been believed that strongly-bonded layers fail by two distinct mechanisms: (i) internal/external penny-shaped crack nucleation and propagation, and (ii) cavitation, that is, cavity growth leading to fibrillation and then failure. However, recent work has demonstrated that cavitation itself is predominantly a fracture process. While the equations describing cavitation from a macroscopic or top-down view are now known and validated with experiments, several aspects of the cavitation crack growth need to be better understood. Notably, cavitation often involves through-thickness crack growth parallel to the loading direction, raising questions about when it initiates instead of the more typical penny-shaped cracks perpendicular to the load. Understanding and controlling the two vertical and horizontal crack growth is key to developing tougher soft films and adhesives. The purpose of this Letter is to provide an explanation for the load-parallel crack growth through a comprehensive numerical analysis and highlight the role of various material and geometrical parameters.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"80 ","pages":"Article 102406"},"PeriodicalIF":4.5,"publicationDate":"2025-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145106186","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}
Pub Date : 2025-09-12DOI: 10.1016/j.eml.2025.102405
Yi Jin , Christian A. Zorman , Changyong Chase Cao
Integrating sensors onto thin-walled tubular structures is of paramount importance for the advancement of smart infrastructures and facilities, enabling real-time detection of mechanical states and environmental conditions. This study systematically investigates the mechanics of bonded sensor layers in suppressing bending-induced ovalization, buckling, and failure in soft, thin-walled tubes, with the goal of enhancing sensing reliability. While significant progress has been made in understanding instability phenomena in tubular structures under mechanical loading, a critical gap remains in characterizing how bonded sensor layers influence deformation and failure mechanisms. To address this, a comprehensive parametric analysis—supported by finite element simulations and experimental validation—was conducted to evaluate the effects of four key parameters: length ratio, thickness ratio, wrapped angle, and relative stiffness. The results reveal that optimized configurations—specifically, length ratios exceeding 0.7, thickness ratios above 1.6, moderate wrapped angles (approximately 2π/3–4π/3), and relative stiffness greater than 0.03—can suppress ovalization to below 25 % in sensor-covered regions, redistribute deformation to uncovered segments, and trigger complex buckling behaviors involving multiple kinks and secondary instabilities. These thresholds mitigate localized strain concentrations, reduce the risk of sensor layer wrinkling or delamination, and preserve measurement fidelity under operational loading. The findings extend classical instability theories to hyperelastic, multilayered systems and provide practical design guidelines for sensor-integrated tubular structures. Applications include smart pipelines and conduits for structural health monitoring and environmental sensing in next-generation infrastructure systems.
{"title":"Mechanics of bonded sensor layers in soft tubes: Suppressing instability and failure for sensing reliability","authors":"Yi Jin , Christian A. Zorman , Changyong Chase Cao","doi":"10.1016/j.eml.2025.102405","DOIUrl":"10.1016/j.eml.2025.102405","url":null,"abstract":"<div><div>Integrating sensors onto thin-walled tubular structures is of paramount importance for the advancement of smart infrastructures and facilities, enabling real-time detection of mechanical states and environmental conditions. This study systematically investigates the mechanics of bonded sensor layers in suppressing bending-induced ovalization, buckling, and failure in soft, thin-walled tubes, with the goal of enhancing sensing reliability. While significant progress has been made in understanding instability phenomena in tubular structures under mechanical loading, a critical gap remains in characterizing how bonded sensor layers influence deformation and failure mechanisms. To address this, a comprehensive parametric analysis—supported by finite element simulations and experimental validation—was conducted to evaluate the effects of four key parameters: length ratio, thickness ratio, wrapped angle, and relative stiffness. The results reveal that optimized configurations—specifically, length ratios exceeding 0.7, thickness ratios above 1.6, moderate wrapped angles (approximately 2π/3–4π/3), and relative stiffness greater than 0.03—can suppress ovalization to below 25 % in sensor-covered regions, redistribute deformation to uncovered segments, and trigger complex buckling behaviors involving multiple kinks and secondary instabilities. These thresholds mitigate localized strain concentrations, reduce the risk of sensor layer wrinkling or delamination, and preserve measurement fidelity under operational loading. The findings extend classical instability theories to hyperelastic, multilayered systems and provide practical design guidelines for sensor-integrated tubular structures. Applications include smart pipelines and conduits for structural health monitoring and environmental sensing in next-generation infrastructure systems.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"80 ","pages":"Article 102405"},"PeriodicalIF":4.5,"publicationDate":"2025-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145106252","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}
Pub Date : 2025-09-04DOI: 10.1016/j.eml.2025.102404
Somya Ranjan Patro , Hemant Sharma , Seokgyu Yang , Jinkyu Yang
Negative extensibility refers to the category of mechanical metamaterials that exhibit an unusual phenomenon where the system contracts upon tension. The dynamic analysis of such systems is crucial for exploring the vibration isolation characteristics, forming the prime focus of the present study. Inspired by Braess’s paradox, the mechanical model incorporates coupled tunable nonlinear spring stiffness properties (strain hardening and softening), which alternate when a certain displacement threshold is exceeded. This stiffness-switching mechanism facilitates wide-frequency passive vibration isolation using the phenomenon of counter-snapping instability. The vibration isolation characteristics resulting from the stiffness-switching mechanism are investigated using time- and frequency-domain plots. Furthermore, the relationship between the stiffness switching mechanism and various system parameters is visualized using a three-dimensional parametric space. The efficacy of the proposed system is evaluated by comparing it with the existing bi-stable systems, revealing superior performance in isolating high-amplitude vibrations. The proposed mechanism enhances the understanding of dynamic behaviors in critical structural elements for multi-stable mechanical metamaterials, providing insights and opportunities for innovative adaptive designs.
{"title":"Passive vibration isolation characteristics of negative extensibility metamaterials","authors":"Somya Ranjan Patro , Hemant Sharma , Seokgyu Yang , Jinkyu Yang","doi":"10.1016/j.eml.2025.102404","DOIUrl":"10.1016/j.eml.2025.102404","url":null,"abstract":"<div><div>Negative extensibility refers to the category of mechanical metamaterials that exhibit an unusual phenomenon where the system contracts upon tension. The dynamic analysis of such systems is crucial for exploring the vibration isolation characteristics, forming the prime focus of the present study. Inspired by Braess’s paradox, the mechanical model incorporates coupled tunable nonlinear spring stiffness properties (strain hardening and softening), which alternate when a certain displacement threshold is exceeded. This stiffness-switching mechanism facilitates wide-frequency passive vibration isolation using the phenomenon of counter-snapping instability. The vibration isolation characteristics resulting from the stiffness-switching mechanism are investigated using time- and frequency-domain plots. Furthermore, the relationship between the stiffness switching mechanism and various system parameters is visualized using a three-dimensional parametric space. The efficacy of the proposed system is evaluated by comparing it with the existing bi-stable systems, revealing superior performance in isolating high-amplitude vibrations. The proposed mechanism enhances the understanding of dynamic behaviors in critical structural elements for multi-stable mechanical metamaterials, providing insights and opportunities for innovative adaptive designs.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"80 ","pages":"Article 102404"},"PeriodicalIF":4.5,"publicationDate":"2025-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145106253","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}
Pub Date : 2025-09-02DOI: 10.1016/j.eml.2025.102403
Wenjian Nie , Lan Xu , Wenjie Xia
Attaining an in-depth understanding of the underlying factors dictating mechanical and macroscopic properties is crucial for establishing structure–property relationships in cross-linked thermosetting polymers. The introduction of additives into these polymers can lead to significant alterations in topology, dynamic behavior, and mechanical properties. In this study, we employ a coarse-grained (CG) polymer model to systematically explore the influences of additive-polymer intermolecular interaction strength , additive mass fraction , and cross-link density on the temperature-dependent mechanical behaviors of a cross-linked glass-forming thermoset. Our results demonstrate that the mechanical characteristics, particularly the tensile and shear moduli, are predominantly affected by and , with a clear temperature dependence across the glassy regime. The modulus outcomes reveal contrasting trends between the neutral interaction system and the strong interaction system . Intriguingly, varying yields distinct scaling relationships between modulus and reduced temperature , indicating a shift from the behavior typically observed in cross-linked thermosets without additives. Moreover, we identify a correlation between the moduli and the Debye–Waller parameter , providing insight into the local stiffness at the molecular level. Our results highlight the critical role of additives and their intermolecular interactions with polymers in governing the mechanical responses of cross-linked network, offering insights for molecular design of thin films, coatings, and nanocomposite systems.
深入了解决定机械和宏观性能的潜在因素对于建立交联热固性聚合物的结构-性能关系至关重要。在这些聚合物中加入添加剂会导致拓扑结构、动态行为和机械性能的显著改变。在本研究中，我们采用粗粒（CG）聚合物模型系统地探讨了添加剂-聚合物分子间相互作用强度εap、添加剂质量分数m和交联密度c对交联玻璃成型热固性材料的温度依赖力学行为的影响。我们的研究结果表明，力学特性，特别是拉伸和剪切模量，主要受εap和m的影响，在整个玻璃态中具有明显的温度依赖性。模量结果揭示了中性相互作用体系εap=1与强相互作用体系εap>；1之间的变化趋势。有趣的是，不同的εap在模量和还原温度T/Tg之间产生了不同的标度关系，这表明在没有添加剂的交联热固性材料中通常观察到的行为发生了转变。此外，我们确定了模量与Debye-Waller参数< u2 >之间的相关性，从而在分子水平上深入了解局部刚度。我们的研究结果强调了添加剂及其与聚合物的分子间相互作用在控制交联网络力学响应中的关键作用，为薄膜、涂层和纳米复合系统的分子设计提供了见解。
{"title":"Influence of additive–polymer interactions on the mechanical behaviors of cross-linked polymers","authors":"Wenjian Nie , Lan Xu , Wenjie Xia","doi":"10.1016/j.eml.2025.102403","DOIUrl":"10.1016/j.eml.2025.102403","url":null,"abstract":"<div><div>Attaining an in-depth understanding of the underlying factors dictating mechanical and macroscopic properties is crucial for establishing structure–property relationships in cross-linked thermosetting polymers. The introduction of additives into these polymers can lead to significant alterations in topology, dynamic behavior, and mechanical properties. In this study, we employ a coarse-grained (CG) polymer model to systematically explore the influences of additive-polymer intermolecular interaction strength <span><math><mfenced><msub><mrow><mi>ε</mi></mrow><mrow><mi>ap</mi></mrow></msub></mfenced></math></span>, additive mass fraction <span><math><mrow><mfenced><mrow><mi>m</mi></mrow></mfenced></mrow></math></span>, and cross-link density <span><math><mrow><mfenced><mrow><mi>c</mi></mrow></mfenced></mrow></math></span> on the temperature-dependent mechanical behaviors of a cross-linked glass-forming thermoset. Our results demonstrate that the mechanical characteristics, particularly the tensile and shear moduli, are predominantly affected by <span><math><msub><mrow><mi>ε</mi></mrow><mrow><mi>ap</mi></mrow></msub></math></span> and <span><math><mi>m</mi></math></span>, with a clear temperature dependence across the glassy regime. The modulus outcomes reveal contrasting trends between the neutral interaction system <span><math><mfenced><mrow><msub><mrow><mi>ε</mi></mrow><mrow><mi>ap</mi></mrow></msub><mo>=</mo><mn>1</mn></mrow></mfenced></math></span> and the strong interaction system <span><math><mfenced><mrow><msub><mrow><mi>ε</mi></mrow><mrow><mi>ap</mi></mrow></msub><mo>></mo><mn>1</mn></mrow></mfenced></math></span>. Intriguingly, varying <span><math><msub><mrow><mi>ε</mi></mrow><mrow><mi>ap</mi></mrow></msub></math></span> yields distinct scaling relationships between modulus and reduced temperature <span><math><mrow><mi>T</mi><mo>/</mo><msub><mrow><mi>T</mi></mrow><mrow><mi>g</mi></mrow></msub></mrow></math></span>, indicating a shift from the behavior typically observed in cross-linked thermosets without additives. Moreover, we identify a correlation between the moduli and the Debye–Waller parameter <span><math><mrow><mi>〈</mi><msup><mrow><mi>u</mi></mrow><mrow><mn>2</mn></mrow></msup><mi>〉</mi></mrow></math></span>, providing insight into the local stiffness at the molecular level. Our results highlight the critical role of additives and their intermolecular interactions with polymers in governing the mechanical responses of cross-linked network, offering insights for molecular design of thin films, coatings, and nanocomposite systems.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"80 ","pages":"Article 102403"},"PeriodicalIF":4.5,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145333148","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}
Pub Date : 2025-08-31DOI: 10.1016/j.eml.2025.102399
Chenghai Li , Shao-Chen Tseng , Yu Zhou , Chieh-Hao Hsu , Wei-Hsiang Tu , Kuo-Chin Chang , Jun He , Zhigang Suo
Semiconductor devices integrate dissimilar materials, including semiconductors, ceramics, metals, and polymers. These materials have different coefficients of thermal expansion, so that the devices develop stresses when temperature changes. Here we study a failure mode caused by cyclic changes in temperature. Under certain conditions, thermal cycling causes a metal to accumulate plastic deformation cycle by cycle, a phenomenon called ratcheting. The ratcheting in the metal can drive a crack to grow in a nearby brittle material. We simulate a representative structure using the finite element method. As the temperature cycles, the plastic deformation in the metal ratchets, and the energy release rate of the crack in the brittle material increases. After a large number of temperature cycles, the metal no longer ratchets, and the energy release rate plateaus. We find that this plateau is well approximated by the energy release rate in a structure where the metal is replaced by a void, calculated by a monotonic change in temperature. This simplification reduces computational cost for modeling ratcheting induced cracking. We also examine the effects of material and geometric parameters. It is hoped that this study will aid the design of semiconductor devices.
{"title":"Ratcheting induced crack growth in semiconductor devices","authors":"Chenghai Li , Shao-Chen Tseng , Yu Zhou , Chieh-Hao Hsu , Wei-Hsiang Tu , Kuo-Chin Chang , Jun He , Zhigang Suo","doi":"10.1016/j.eml.2025.102399","DOIUrl":"10.1016/j.eml.2025.102399","url":null,"abstract":"<div><div>Semiconductor devices integrate dissimilar materials, including semiconductors, ceramics, metals, and polymers. These materials have different coefficients of thermal expansion, so that the devices develop stresses when temperature changes. Here we study a failure mode caused by cyclic changes in temperature. Under certain conditions, thermal cycling causes a metal to accumulate plastic deformation cycle by cycle, a phenomenon called ratcheting. The ratcheting in the metal can drive a crack to grow in a nearby brittle material. We simulate a representative structure using the finite element method. As the temperature cycles, the plastic deformation in the metal ratchets, and the energy release rate of the crack in the brittle material increases. After a large number of temperature cycles, the metal no longer ratchets, and the energy release rate plateaus. We find that this plateau is well approximated by the energy release rate in a structure where the metal is replaced by a void, calculated by a monotonic change in temperature. This simplification reduces computational cost for modeling ratcheting induced cracking. We also examine the effects of material and geometric parameters. It is hoped that this study will aid the design of semiconductor devices.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"80 ","pages":"Article 102399"},"PeriodicalIF":4.5,"publicationDate":"2025-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144934285","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}
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