Xinwei Yang , Chunwang He , Jie Yang , Yikun Wu , Le Yang , Hao-Sen Chen
{"title":"Data-driven scheme for two-scale chemo-mechanical coupled problem for heterogeneous materials under transient chemical diffusion","authors":"Xinwei Yang , Chunwang He , Jie Yang , Yikun Wu , Le Yang , Hao-Sen Chen","doi":"10.1016/j.eml.2025.102363","DOIUrl":"10.1016/j.eml.2025.102363","url":null,"abstract":"<div><div>This study developed a data-driven computational scheme of multiscale multiphysics coupled problem for heterogeneous materials under transient chemical diffusion. Firstly, the data-driven scheme decouples the multiscale problem into two stages, i.e., offline generation of material constitutive behavior database by microscopic simulation, and online macroscopic boundary value problem (BVP) based on the data-driven mechanical scheme. In addition, data-driven scheme converts the multiphysics coupled constitutive relationship into the material conjugate quantities in database which avoids the poor convergence in multiscale multiphysics coupled calculation. Then, a two-scale chemo-mechanical model with a simple microstructure is validated in two cases: diffusion-induced mechanical deformation and deformation-enhanced chemical diffusion. The results show that the proposed framework can characterize the chemo-mechanical coupled behavior with good convergence and accuracy, which is more efficient than the full-scale finite element simulation. Finally, this data-driven scheme is applied to analyze the multilayer porosity structures for lithium-ion battery cathodes. The results show that cathodes with gradient porosity design can improve the utilization of active materials and enhance the effective capacity.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"78 ","pages":"Article 102363"},"PeriodicalIF":4.3,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144253386","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}
Yun Shi , Jiali Cheng , Guangyuan Su , Meiying Zhao , Yongquan Liu , Bing Li
{"title":"Defected elastic metasurfaces for structured focusing with the extension of Babinet principle","authors":"Yun Shi , Jiali Cheng , Guangyuan Su , Meiying Zhao , Yongquan Liu , Bing Li","doi":"10.1016/j.eml.2025.102366","DOIUrl":"10.1016/j.eml.2025.102366","url":null,"abstract":"<div><div>Defects offer a new geometric freedom in metamaterials or phononic crystals to functionally modulate waves, but remain unexplored in a low-dimensional version of artificial structures. We here introduce the concept of a defected metasurface that enables structured focusing by breaking the traditional design notion of perfect metasurfaces for single focus. We theoretically and experimentally demonstrate that the distance between focal points is smaller than the wavelength, which is a challenging task previously. Moreover, the number and the energy distribution of foci can be tailored via integrating defects with the metasurface, which can be well described based on the Babinet principle. We further realize the Talbot effect to generate periodically focusing and digital coding. This defected prototype offers a promising strategy to shape structured elastic waves for nondestructive testing, and may be extended to other fields on the design of efficient acoustic or optical tweezer arrays.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"78 ","pages":"Article 102366"},"PeriodicalIF":4.3,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144242040","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}
R. Pramanik , M. Park , Z. Ren , M. Sitti , R.W.C.P. Verstappen , P.R. Onck
{"title":"Computational and experimental design of fast and versatile magnetic soft robotic low Re swimmers","authors":"R. Pramanik , M. Park , Z. Ren , M. Sitti , R.W.C.P. Verstappen , P.R. Onck","doi":"10.1016/j.eml.2025.102358","DOIUrl":"10.1016/j.eml.2025.102358","url":null,"abstract":"<div><div>Miniaturized magnetic soft robots have shown extraordinary capabilities of contactless manipulation, complex path maneuvering, precise localization, and rapid actuation, enabling them to cater to challenging biomedical applications such as targeted drug delivery, internal wound healing, and laparoscopic surgery. However, despite their successful fabrication by several different research groups, a thorough design strategy encompassing the optimized kinematic performance of the three fundamental biomimetic swimming modes at miniaturized length scales has not been reported until now. Here, we resolve this by designing magnetic soft robotic swimmers (MSRSs) from the class of helical and undulatory low Reynolds number (Re) swimmers using a fully coupled, experimentally calibrated computational fluid dynamics model. We study (and compare) their swimming performance, and report their steady-state swimming speed for different non-dimensional numbers that capture the competition by magnetic loading, nonlinear elastic deformation, and viscous solid–fluid coupling. We investigated their stability for different initial spatial orientations to ensure robustness during real-life applications. Our results show that the helical ’finger-shaped’ swimmer is by far the fastest low Re swimmer in terms of body lengths per cycle, but that the undulatory ’carangiform-like’ swimmer proved to be the most versatile, bidirectional swimmer with maximum stability.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"78 ","pages":"Article 102358"},"PeriodicalIF":4.3,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144221197","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}
Brandon K. Zimmerman , Rebecca Schulman , Thao D. Nguyen
{"title":"Growth-induced Donnan exclusion influences swelling kinetics in highly charged dynamic polymerization hydrogels","authors":"Brandon K. Zimmerman , Rebecca Schulman , Thao D. Nguyen","doi":"10.1016/j.eml.2025.102354","DOIUrl":"10.1016/j.eml.2025.102354","url":null,"abstract":"<div><div>Polymeric gels crosslinked by DNA sequences can exploit DNA strand-displacement reactions to promote swelling through dynamic polymerization. The degree of swelling and the rate of swelling must be directly tunable to achieve the promise of programmable soft matter. Though the kinetics of the strand-displacement reaction provide insertion rates up to <span><math><mrow><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>4</mn></mrow></msup></mrow></math></span>/Molar/second as measured in bulk solution, DNA hydrogel swelling can take upwards of 30 h to complete. Computational modeling of the reaction-induced swelling of these gels with our recently-developed reactive electrochemomechanical theory (Zimmerman et al., 2024) suggests that their extraordinarily slow swelling is partly due to a scaling mismatch between the addition of charge and the addition of fluid volume, leading to a large transient increase in the fixed charge density. The significant increase in the gel’s fixed charge density, due to the binding of negatively charged DNA, sharply restricts the concentration of mobile hairpins through the phenomenon of Donnan charge exclusion, an effect commonly exploited in nanofiltration applications using polymeric membranes. The scaling problem is overcome when the mean additional swelling provided to the hydrogel by addition of a crosslink is above a critical value, thus the swelling outpaces the charge accumulation, leading the fixed charge density to drop and significantly accelerating the swelling process. This study shows that Donnan exclusion can explain the kinetics of DNA hydrogel swelling, and studies ways to modulate the reaction speed by either modifying the salt concentration or increasing or decreasing the number of base pairs in each DNA sequence.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"78 ","pages":"Article 102354"},"PeriodicalIF":4.3,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144221198","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}
Peidong Zhang , Tong Zhou , Kuan Zhang , Yifei Luo , Yang Li
{"title":"Corrigendum to “High-stiffness reconfigurable surfaces based on bistable element assembly and bi-compatible truss attachment’’ [Extreme Mech. Lett. 71 (September) (2024) 102187]","authors":"Peidong Zhang , Tong Zhou , Kuan Zhang , Yifei Luo , Yang Li","doi":"10.1016/j.eml.2025.102303","DOIUrl":"10.1016/j.eml.2025.102303","url":null,"abstract":"","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"77 ","pages":"Article 102303"},"PeriodicalIF":4.3,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144196185","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}
Jingping Wu, Zhengjin Wang, Xiao Liu, Yong Zheng, Yang Gao, Jian Hu
{"title":"Water-abundant and tough structured composite hydrogels via ion transfer printing","authors":"Jingping Wu, Zhengjin Wang, Xiao Liu, Yong Zheng, Yang Gao, Jian Hu","doi":"10.1016/j.eml.2025.102367","DOIUrl":"10.1016/j.eml.2025.102367","url":null,"abstract":"<div><div>Hydrogels with high water content and toughness are essential to various applications in smart materials and biomimetic systems. However, there exists a conflict between water content and toughness. To enhance toughness, high polymer chain density or water-free reinforcements are usually introduced into hydrogel matrices, which inevitably lead to a reduction in water content. In this study, we present a facile method for preparing water-abundant and tough hydrogels through ion transfer printing. By utilizing sodium alginate/polyacrylamide (Alg/PAAm) hydrogels as a flexible matrix and Fe<sup>3+</sup> ions as stiffening agents, we selectively introduce Fe<sup>3+</sup> ions into predefined regions of the hydrogel matrix, resulting in well-structured composite hydrogels comprising soft Alg/PAAm matrix and hard Fe<sup>3+</sup>-crosslinked Alg/PAAm (Fe-Alg/PAAm) fibers. As both the matrix and fibers are stretchable and water-abundant, the composites exhibit impressive stretchability (<em>ε</em>∼1000 %) and water content (<em>p</em>∼95 %). Notably, the alternating arrangement of the soft and hard fiber/matrix architecture effectively prevents crack propagation during loading by inducing stress deconcentration at the crack tip, thereby leading to exceptional toughness (<em>Γ</em>∼22000 J/m<sup>2</sup>). This simple method introduces a universal design strategy for constructing stretchable, water-abundant, and tough hydrogels, considering that ionic crosslinking with multi-valent cation crosslinkers is widely used in hydrogels. Beyond the Fe<sup>3+</sup> and Alg/PAAm hydrogel system discussed here, this concept can be extended to various combinations of multi-valent ions and hydrogel networks containing opposite charges.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"78 ","pages":"Article 102367"},"PeriodicalIF":4.3,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144212926","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}
Shaohua Yang , Yue Liu , Yukun Su , Han Gao , Kaiqiang Sun , Qin Xu , Qiuting Zhang , Ye Xu
{"title":"Three-dimensional imaging and measurement of the microscale deformation in soft thin films under micro-indentation","authors":"Shaohua Yang , Yue Liu , Yukun Su , Han Gao , Kaiqiang Sun , Qin Xu , Qiuting Zhang , Ye Xu","doi":"10.1016/j.eml.2025.102355","DOIUrl":"10.1016/j.eml.2025.102355","url":null,"abstract":"<div><div>Micro-indentation has been used in measuring mechanical properties of soft materials. However, the complex contact mechanics of soft interfaces pose challenges in the accurate characterization of mechanical parameters from conventional measurement methods. In this work, we present an <em>in situ</em> imaging setup capable of measuring three-dimensional (3D) microscale deformation of soft elastic thin films subjected to a microindenter. Combining fluorescent confocal imaging and particle tracking techniques, microscale surface displacement profiles and stress–strain distributions are accurately quantified. Using this technique, we directly compare microscopic deformations in thin soft films with a thickness range, demonstrating the transition from “sink-in” to “pile-up” as the thickness of the film decreases. We also reveal an intricate difference in displacement fields for different lubrication conditions between the microindenter and soft thin film. These results demonstrate the capacity of our experimental setup as a powerful tool in understanding the unique micro-mechanical behaviors of various soft materials.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"78 ","pages":"Article 102355"},"PeriodicalIF":4.3,"publicationDate":"2025-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144231274","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":"Hydrostatic pressure suppresses the electrical breakdown of flexible-rigid interfaces under deep-sea","authors":"Dingnan Rao , Fanghao Zhou , Zheng Chen , Tiefeng Li","doi":"10.1016/j.eml.2025.102353","DOIUrl":"10.1016/j.eml.2025.102353","url":null,"abstract":"<div><div>High-voltage and high-power electronic components intended for deep-sea applications encounter various challenges, including high hydrostatic pressure, temperature fluctuations, and probable seawater ingress. Consequently, encapsulation of deep-sea electronics that provides both efficient electrical insulation and pressure tolerance is crucial. This study investigates the influence of high hydrostatic pressure up to tens of MPa on the electrical breakdown of the flexible-rigid encapsulation interface, using polydimethylsiloxane and FR-4 glass epoxy as experimental materials. The experimental results show that the interface breakdown strength increases with hydrostatic pressure, in which a rapid increase is observed at 0.1<!--> <!-->MPa to 0.75<!--> <!-->MPa, followed by a slower rise at 0.75<!--> <!-->MPa to 30.0<!--> <!-->MPa. To explain this phenomenon, the cavity discharge inception field and the enhanced local electric field at contact spots under hydrostatic pressure were calculated based on interfacial contact theory. At relatively lower pressures, cavity discharge predominates in driving the interface breakdown, and the rapid growth of cavity discharge inception field leads to the sharp increase in breakdown strength with hydrostatic pressure. Whereas at higher pressures, the insulation properties of contact spots become the dominant factor. Post-breakdown analyses, including optical microscopy and micro-CT imaging, reveal that high hydrostatic pressure suppresses damage propagation, such as material carbonization, electrode defects, and gas formation. These results indicate that hydrostatic pressure helps suppress the electrical breakdown of the flexible-rigid interface. This study provides insights into the electrical breakdown behavior of flexible-rigid interfaces under high hydrostatic pressure, offering implications for the encapsulation design and optimization of deep-sea electronic components.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"78 ","pages":"Article 102353"},"PeriodicalIF":4.3,"publicationDate":"2025-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144185435","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}
HaoWen Wan , YuanZhen Hou , JiaHao Li , RongZhuang Song , YinBo Zhu , HengAn Wu
{"title":"A coarse-grained model for nanocellulose with hydration interfaces revealing the anomalous mechanical enhancement","authors":"HaoWen Wan , YuanZhen Hou , JiaHao Li , RongZhuang Song , YinBo Zhu , HengAn Wu","doi":"10.1016/j.eml.2025.102361","DOIUrl":"10.1016/j.eml.2025.102361","url":null,"abstract":"<div><div>Considering the humidity-sensitivity of nanocellulose, decoding the micromechanical mechanisms hidden in hydration interface is essential for tailoring the macroscopic properties. However, exiting mechanics frameworks based on molecular modeling remain challenging to predict the hydration interface-mediated mechanical behaviors of nanocellulose at the mesoscale, hindering the correlation from micro-interface to macro-mechanics. Herein, we developed a coarse-grained (CG) model integrating non-covalent interactions and fiber-level hierarchical stacking, which unveils the anomalous mechanical enhancement of nanocellulose with hydration interfaces. The CG model, validated by all-atom (AA) simulations, accurately captured the modulus and strength scale law with overlap length, until the fiber fracture-dominated saturated state. Our results revealed how hydration extent effects the interfacial mechanics, showing that moderate hydration can enhance both toughness and strength by plasticizing hydrogen-bonding networks, while excessive hydration weakening the shear strength. Beyond the limit that AA simulations can predict, an optimal overlap regime (∼120–180 nm) was identified, where hydration-mediated interfaces can enhance the strength and toughness simultaneously. This study established a cross-scale theoretical modeling framework bridging the microscale hydration interface and macroscale mechanical regulation of nanocellulose materials, which can provide the bottom-up rational guidance for designing strong and tough nanocomposites with weak non-covalent interfaces.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"78 ","pages":"Article 102361"},"PeriodicalIF":4.3,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144167210","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}