Extreme Mechanics Letters最新文献

{"title":"High-precision fluidic Kirigami morphing surface for ultrasonic holographic lensing and haptic interfacing","authors":"Ardalan Kahak ,&nbsp;Moustafa Sayed Ahmed ,&nbsp;Nahid Kalantaryardebily ,&nbsp;Hrishikesh Kulkarni ,&nbsp;Netta Gurari ,&nbsp;Shima Shahab ,&nbsp;Suyi Li","doi":"10.1016/j.eml.2025.102424","DOIUrl":"10.1016/j.eml.2025.102424","url":null,"abstract":"<div><div>Morphing surfaces provide a versatile tool to advance the functionalities of high-performance aircraft, soft robots, biomedical devices, and human–machine interfaces. However, achieving <em>precise</em> shape transformation and mechanical property control remains challenging due to nonlinearity, design constraints, and the difficulty of coordinating multiple constituent materials across a continuous surface. To this end, this study unveils that Kirigami art can inspire novel solutions. More specifically, the geometric principles of Kirigami can be exploited to design and fabricate fluidic morphing surfaces capable of highly accurate shape morphing and output force control, all via a single pressure input. This study presents a systematic approach to designing Kirigami for tuning the local deformation and force output through extensive nonlinear modeling and experiment validation on two archetypal patterns: concentric square and circular cuts. The potentials of this approach are demonstrated via two multiphysics case studies: (1) an acoustic holography lens for ultrasonic wave steering, achieving highly accurate deformation control under a single global pressure input, and (2) a haptic device with a small volume, constant contact area, and high-resolution output force. The fluidic Kirigami concept allows for simple yet effective adaptation to different shape and stiffness requirements, paving the way for a new family of scalable and programmable morphing surfaces.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"81 ","pages":"Article 102424"},"PeriodicalIF":4.5,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145579561","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}

{"title":"Exploring conformational landscapes of two-dimensional macromolecules via well-tempered metadynamics","authors":"Yanyan Zhao ,&nbsp;Ke Zhou ,&nbsp;Yan Chen ,&nbsp;Yilun Liu","doi":"10.1016/j.eml.2025.102421","DOIUrl":"10.1016/j.eml.2025.102421","url":null,"abstract":"<div><div>Exploring conformational landscape of two-dimensional (2D) macromolecules poses a profound challenge due to their intrinsically complex free energy surfaces. Conventional computational approaches based on equilibrium molecular dynamics (MD) suffer from limited ergodic exploration, failing to adequately explore energy landscapes and transition pathways between metastable conformations. In this study, we employ well-tempered Metadynamics simulations with carefully designed collective variables to comprehensively map conformational space of 2D macromolecules. Our systematic exploration reveals three distinct metastable states, i.e., flat, fold and scroll conformations. Through detailed free energy analysis, we elucidate the delicate interplay between bending rigidity and interlayer adhesion that govern free energy surfaces of these conformations. Furthermore, we propose a temperature-modulated strategy to regulate conformational transitions among the three states. By decomposing the total free energy into entropic and enthalpic contributions, we quantitatively characterize the temperature-dependent thermodynamic driving forces underlying conformational transformations. This research establishes a robust computational framework for quantifying free energy and entropy associated with metastable conformations in 2D macromolecule systems. Our findings advance fundamental understanding of conformational transitions, regulation processes, and self-assembly behaviors in 2D macromolecular systems.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"81 ","pages":"Article 102421"},"PeriodicalIF":4.5,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145579622","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}

{"title":"Viscoelasticity and crack growth in tanglemers","authors":"Yu Zhou ,&nbsp;Xianyang Bao ,&nbsp;Zhigang Suo","doi":"10.1016/j.eml.2025.102418","DOIUrl":"10.1016/j.eml.2025.102418","url":null,"abstract":"<div><div>A tanglemer is a polymer network in which chains are long, and entanglements greatly outnumber crosslinks. In a tanglemer, each chain is divided by crosslinks into many strands, and each strand is divided by entanglements into many segments. In synthesizing tanglemers, the crosslink density is readily varied, but the entanglement density is set by the chemistry of the polymer. Here we investigate how crosslink density affects the mechanical behavior of tanglemers. We find that viscoelasticity is unaffected by crosslink density when tanglemers are subject to stretches small enough without breaking strands. We then study crack growth in tanglemers under a static load. A load exists, called the slow-crack threshold, below which the crack does not grow. The threshold is high in a tanglemer of low crosslink density. Fast crack growth, however, is insensitive to crosslink density. We discuss how molecular mechanisms affect mechanical behavior.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"81 ","pages":"Article 102418"},"PeriodicalIF":4.5,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145529018","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}

{"title":"When and where do large cracks grow? Griffith energy competition constrained by material strength","authors":"Oscar Lopez-Pamies,&nbsp;Farhad Kamarei","doi":"10.1016/j.eml.2025.102417","DOIUrl":"10.1016/j.eml.2025.102417","url":null,"abstract":"<div><div>An abundance of comparisons with experimental evidence has long settled that the Griffith energy competition along a known crack path — commonly expressed as a criticality condition on the energy release rate — describes <em>when</em> a large crack grows in a nominally elastic brittle material that is subjected to quasi-static loading. However, the answer to the question of <em>where</em> — that is, in which direction — a large crack grows remains unresolved. A slew of criteria have been proposed over the decades, but comparisons with experiments have indicated that none of such criteria apply in general.</div><div>Directly guided by the mathematical structure of the regularized phase-field theory of fracture initiated by Kumar, Francfort, and Lopez-Pamies (<em>J. Mech. Phys. Solids</em> 112 (2018), 523–551), and motivated by the wide range of experiments that this theory has been validated against, this Letter introduces a new criterion to describe when and where large cracks grow in elastic brittle materials under quasi-static loading conditions. In a nutshell: <em>the growth of a large crack takes place within and only within regions where the strength surface of the material has been exceeded, this in a manner such that the sum of the potential (that is, the elastic energy minus the work of the external loads) and surface energies are minimized</em>. Importantly, this strength-constrained Griffith-energy-competition criterion is general in the sense that it applies to materials with any elasticity (linear or nonlinear) and any material symmetry (isotropic or anisotropic). In this Letter, for simplicity of presentation, attention is restricted to the most basic of settings, that of isotropic linear elastic brittle materials. Following its raison d’etre by means of a simple example and then general introduction, the proposed criterion is confronted with a set of classical experiments on glass.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"81 ","pages":"Article 102417"},"PeriodicalIF":4.5,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145475483","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}

{"title":"Front cover CO1","authors":"","doi":"10.1016/S2352-4316(25)00127-0","DOIUrl":"10.1016/S2352-4316(25)00127-0","url":null,"abstract":"","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"80 ","pages":"Article 102415"},"PeriodicalIF":4.5,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145424414","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}

{"title":"On failure mechanisms and load-parallel cracking in confined elastomeric layers","authors":"Aarosh Dahal,&nbsp;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":"2025-11-01","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}

{"title":"Mechanics of bonded sensor layers in soft tubes: Suppressing instability and failure for sensing reliability","authors":"Yi Jin ,&nbsp;Christian A. Zorman ,&nbsp;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":"2025-11-01","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}

{"title":"Precipitate response in GRCop-42 metallic microparticles under extreme impact conditions","authors":"Jianxiong Li ,&nbsp;Yuan Yao ,&nbsp;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 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.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"80 ","pages":"Article 102410"},"PeriodicalIF":4.5,"publicationDate":"2025-11-01","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}

{"title":"Tracing back transient information from near-stationary random data","authors":"Xi Chen ,&nbsp;Xiaoling Jin ,&nbsp;Yong Wang ,&nbsp;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":"2025-11-01","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}

{"title":"Influence of additive–polymer interactions on the mechanical behaviors of cross-linked polymers","authors":"Wenjian Nie ,&nbsp;Lan Xu ,&nbsp;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>&gt;</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":"2025-11-01","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}