Extreme Mechanics Letters最新文献

{"title":"Origami electronic membranes as highly shape-morphable mechanical and environmental sensing systems","authors":"Yao Yao ,&nbsp;Guanghui Li ,&nbsp;Xin Ning","doi":"10.1016/j.eml.2024.102264","DOIUrl":"10.1016/j.eml.2024.102264","url":null,"abstract":"<div><div>This work introduces a concept of highly shape-morphable macro-scale origami electronic membranes based on the design and fabrication of flexible electronics and engineering origami. The origami electronic membranes can change shapes, provide multi-modal mechanical and environmental sensing capabilities in room and harsh temperatures, and/or switch functions by mechanical shape reconfiguration. This paper presents the materials, design, and fabrication methods for realizing six origami electronic membranes capable of reconfiguring planar or three-dimensional shapes based on the modified flasher, Kresling, Miura-ori, circular, letter, and Tachi-Miura origami patterns. They can be folded into small, stowed geometries and controllably deployed into larger areas or volumes to cover expanded spaces for spatial sensing, enabling significant shape adaptability for flexible electronics beyond simple stretching or bending. The mechanical and environmental sensing modalities include measuring motions, mechanical strains, temperatures, UV light, and humidity. The results reported here may expand the use of flexible electronics to applications that especially require aggressive shape transitions between a small, folded geometry and a large surface or volume such as deployable sensing systems for space explorations and accessing and monitoring highly confined locations.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"73 ","pages":"Article 102264"},"PeriodicalIF":4.3,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142659222","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":"A large atomic partition model for materials discovery","authors":"Lintao Miao ,&nbsp;Xiaoang Yuan ,&nbsp;Chun Tang ,&nbsp;Changfeng Chen ,&nbsp;Enlai Gao","doi":"10.1016/j.eml.2024.102262","DOIUrl":"10.1016/j.eml.2024.102262","url":null,"abstract":"<div><div>Accurate and efficient prediction of benchmark properties is essential to the discovery of diverse functional materials, but searching vast element combinatorial and bonding configurational spaces presents formidable challenges to current computational techniques. Here, we devise a large atomic partition (LAP) model featuring a scheme to partition material properties into constituent atomic attributes, which are validated by a data-driven calibration procedure and assigned to elements across the periodic table, then utilized as raw ingredients to assemble and assess targeted properties of new materials. Distinct subtypes are designated for each element based on local atomic environments such as coordination number and valence state, and the parameter count of the LAP model can be tuned widely to tailor prediction accuracy and computational efficiency. As demonstrative case studies, we explore volumetric cohesive energy, bulk modulus, and shear modulus, and the results showcase superior accuracy, efficiency, universality, and interpretability of the LAP model compared to alternative approaches. Moreover, based on the predicted elastic moduli, we discover a series of rare and highly sought-after compounds exhibiting concurrent superior hardness and toughness, highlighting the promise of the LAP model in high-throughput screening for advanced materials with targeted outstanding functionalities.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"73 ","pages":"Article 102262"},"PeriodicalIF":4.3,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142659221","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":"Atomic insights into the ductile–brittle competition of cracks under dissolution","authors":"Long Liu,&nbsp;Quanzi Yuan","doi":"10.1016/j.eml.2024.102256","DOIUrl":"10.1016/j.eml.2024.102256","url":null,"abstract":"<div><div>Environmental effects can determine the ductile–brittle behavior of cracks at the atomic scale, but the underlying processes remain poorly understood and contentious. Here, we report the competition between ductile and brittle behaviors at crack tips induced by the prevalent environmental effect of dissolution. Our findings reveal that this competition is driven by two fundamental deformation mechanisms related to dissolution: crack blunting and defect accumulation. Through separate evaluations of dissolution-induced cleavage and dissolution-induced plasticity, we demonstrate that these deformation mechanisms not only dominate brittle fracture toughness but also lead to dislocation slip. We have developed a theoretical model to predict the ductile and brittle behavior of cracks under dissolution, and the theory aligns well with the simulation results and remains consistent with existing experimental trends. This work will broaden the microscopic understanding of ductile and brittle fracture of cracks in complex environments.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"73 ","pages":"Article 102256"},"PeriodicalIF":4.3,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142659220","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":"A model for micro-scale propulsion using flexible rotating flagella","authors":"Yifei Ren,&nbsp;P.K. Purohit","doi":"10.1016/j.eml.2024.102251","DOIUrl":"10.1016/j.eml.2024.102251","url":null,"abstract":"<div><div>Micro-scale propulsion by rotating helical flagella is of interest for the study of bacteria and robotic micro-swimmers. The propulsive thrust and torque produced by the rotating flagella are usually estimated assuming that they are rigid. In this paper we assume the flagella to be deformable elastic rods and compute propulsive forces and torques by enforcing local equilibrium of the rod within the context of resistive force theory. The torque–speed characteristics of the flagellar motor driving the rotation are taken into account. We show that the problem can be cast as a system of algebraic equations if the flagella are assumed to be helical before and after deformation when no spontaneous curvature is included. If the assumption of helical shape is dropped then we show that the propulsion problem can be cast as a system of first order differential equations that can be solved numerically. Our results in both cases agree reasonably well with experimental observations of bacterial propulsion and deviate from the predictions of Purcell depending on the mechanical properties of the flagellum.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"73 ","pages":"Article 102251"},"PeriodicalIF":4.3,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142659219","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(24)00137-8","DOIUrl":"10.1016/S2352-4316(24)00137-8","url":null,"abstract":"","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"72 ","pages":"Article 102257"},"PeriodicalIF":4.3,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142653215","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":"Harnessing centrifugal and Euler forces for tunable buckling of a rotating elastica","authors":"Eduardo Gutierrez-Prieto ,&nbsp;Michael Gomez ,&nbsp;Pedro M. Reis","doi":"10.1016/j.eml.2024.102246","DOIUrl":"10.1016/j.eml.2024.102246","url":null,"abstract":"<div><div>We investigate the geometrically nonlinear deformation and buckling of a slender elastic beam subject to time-dependent ‘fictitious’ (non-inertial) forces arising from unsteady rotation. Using a rotary apparatus that accurately imposes an angular acceleration around a fixed axis, we demonstrate that dynamically coupled centrifugal and Euler forces can produce tunable structural deformations. Specifically, by systematically varying the acceleration ramp in a highly automated experimental setup, we show how the buckling onset of a cantilevered beam can be precisely tuned and its deformation direction selected. In a second configuration, we demonstrate that Euler forces can cause a pre-arched beam to snap-through, on demand, between its two stable states. We also formulate a theoretical model rooted in Euler’s <em>elastica</em> that rationalizes the problem and provides predictions in excellent quantitative agreement with the experimental data. Our findings demonstrate an innovative approach to the programmable actuation of slender rotating structures, where complex loading fields can be produced by controlling a single input parameter, the angular position of a rotating system. The ability to predict and control the buckling behaviors under such non-trivial loading conditions opens avenues for designing devices based on rotational fictitious forces.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"72 ","pages":"Article 102246"},"PeriodicalIF":4.3,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142554550","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Wrinkling of compressible magnetic soft plates","authors":"Guozhan Xia","doi":"10.1016/j.eml.2024.102255","DOIUrl":"10.1016/j.eml.2024.102255","url":null,"abstract":"<div><div>This paper establishes an analytical method for the wrinkling of compressible magnetic soft (MS) plates subject to an in-plane biaxial stretching and an out-of-plane magnetic induction field. The bifurcation analysis is performed with external Maxwell stress considered by combining the surface impedance matrix method and the Stroh formulation in terms of true magnetic field variables. We decouple the resulting bifurcation equations into antisymmetric and symmetric modes and provide the explicit expressions within a neo-Hookean ideal magnetoelastic model. Numerical examples show that the antisymmetric wrinkling usually occurs prior to the symmetric one, unless the permeability of the plates <span><math><mi>μ</mi></math></span> is much smaller than that of the surroundings <span><math><msup><mrow><mi>μ</mi></mrow><mrow><mo>′</mo></mrow></msup></math></span>, i.e., the normalized permeability <span><math><mrow><mrow><mi>μ</mi></mrow><mo>/</mo><mrow><msup><mrow><mi>μ</mi></mrow><mrow><mo>′</mo></mrow></msup></mrow></mrow><mo>→</mo><mn>0</mn></math></span>. This observation is consistent with the previous studies on incompressible case. However, for nearly incompressible plates with <span><math><mrow><mrow><mi>μ</mi></mrow><mo>/</mo><mrow><msup><mrow><mi>μ</mi></mrow><mrow><mo>′</mo></mrow></msup></mrow></mrow><mo>&gt;</mo><mn>1</mn></math></span>, the compressible constitutive relation may impose an additional deformation constraint that noticeably limits the occurrence and extent of wrinkling in the plates. One intriguing observation in particular is that the critical stretches for the thin-plate instability exhibit a nonmonotonic character as the compressibility of plate varies. Release of compressibility plays a positive role on stabilizing the MS plates when <span><math><mrow><mn>0</mn><mrow><mo>&lt;</mo><mrow><mrow><mi>μ</mi></mrow><mo>/</mo><mrow><msup><mrow><mi>μ</mi></mrow><mrow><mo>′</mo></mrow></msup></mrow></mrow><mo>&lt;</mo></mrow><mn>1</mn></mrow></math></span>, yet a negative role when <span><math><mrow><mrow><mi>μ</mi></mrow><mo>/</mo><mrow><msup><mrow><mi>μ</mi></mrow><mrow><mo>′</mo></mrow></msup></mrow></mrow><mo>&gt;</mo><mn>1</mn></math></span>. This phenomenon may be attributed to the coupling effect between the compressibility and the normalized permeability <span><math><mrow><mrow><mi>μ</mi></mrow><mo>/</mo><mrow><msup><mrow><mi>μ</mi></mrow><mrow><mo>′</mo></mrow></msup></mrow></mrow></math></span>, suggesting a potential way to regulate wrinkling behaviors of MS materials by tuning the surrounding permeability. The present work may serve as benchmark solutions for understanding structural failures in various related functional MS-based devices.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"73 ","pages":"Article 102255"},"PeriodicalIF":4.3,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142586582","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":"Crack-growth inhibition by designing dendritic pattern for soft adhesives","authors":"Yifan Zhang ,&nbsp;Danming Zhong ,&nbsp;Qiuxuan Wang ,&nbsp;Ping Rao ,&nbsp;Shaoxing Qu","doi":"10.1016/j.eml.2024.102254","DOIUrl":"10.1016/j.eml.2024.102254","url":null,"abstract":"<div><div>Soft adhesive layers show promise in various engineering applications, including biomedicine, automotive, semiconductor, and aerospace industries. However, cavities trapped at the interface due to poor contact will significantly inhibit their adhesion capacity, leading to rapid crack-growth failure. Significant efforts in these applications within a confined contact area are focused on mitigating the effects and enhancing the debonding work of the interface without changing the materials, such as using bioinspired micropillars. However, soft adhesives with isolated contact elements face limitations due to manufacturing complexity and the collision of micropillars under large deformation. This study proposes a simple and effective method to reduce the hydrostatic pressure around the crack tips by designing a dendritic pattern within the confined area. This approach inhibited interface crack growth well and improved adhesive performance. As a result, the crack failure was delayed, with the stretch ratio enhanced by more than 36 %, while the debonding work increased by 85 % compared with the circular adhesive layer. This study demonstrates that adhesion capacity can be significantly improved while reducing material usage by designing dendritic patterns.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"73 ","pages":"Article 102254"},"PeriodicalIF":4.3,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142578255","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":"Broadband elastic energy harvesting based on achromatic meta-grating","authors":"Yizhou Shen ,&nbsp;Yanlong Xu ,&nbsp;Feng Liu ,&nbsp;Fanglong Wang ,&nbsp;Guan Wang ,&nbsp;Zhichun Yang","doi":"10.1016/j.eml.2024.102253","DOIUrl":"10.1016/j.eml.2024.102253","url":null,"abstract":"<div><div>Energy harvesting exploiting the inverse piezoelectric effect has been the subject of much attention and discussion in the field of elastic and structural dynamics. Recently, the ongoing development of elastic metamaterials and metasurfaces has opened up a new way to improve the quality of energy harvesting. Here, we proposed a new strategy for harvesting elastic energy in a plate, which is the use of the inverse piezoelectric effect to convert the elastic energy into electrical energy after the achromatic meta-grating has focused broadband flexural waves. A new theoretical method to design the achromatic meta-grating is proposed based on derived analytical expression of the phase shift of subunit. When a meta-grating, a thin plate and a piezoelectric patch are combined into an energy harvesting system, the elastic energy can be converted into electric energy by the system, and the output voltage can be amplified by twice that of the system without the meta-grating. A theoretical framework is built to analyze the performance of the energy harvesting system, and variational parametric analyses are carried out to obtain the optimal resistance, the optimal length, thickness and position of piezoelectric patch, which are <span><math><mrow><mn>870</mn><mi>Ω</mi></mrow></math></span>, 18 mm, 0.2 mm and 30 mm, respectively. For the optimized system, the power harvested rate of the system is close to 4 in the frequency band of 6–8 kHz. Finally, the design of the system based on the wave focusing principle is extended, and energy harvesters are designed for different frequency bands, which can all work under different excitation conditions (a local and a base excitations). Our work opens up a new route for elastic energy harvesting and may have broad application prospects in the development of self-powered sensors.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"72 ","pages":"Article 102253"},"PeriodicalIF":4.3,"publicationDate":"2024-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142535951","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":"Understanding the role of chain stiffness in the mechanical response of cross-linked polymer: Flexible vs. semi-flexible chains","authors":"Xiangrui Zheng ,&nbsp;Wenjie Xia ,&nbsp;Yao Zhang","doi":"10.1016/j.eml.2024.102252","DOIUrl":"10.1016/j.eml.2024.102252","url":null,"abstract":"<div><div>Cross-linked polymers are widely used in structural, engineering, and biomedical applications due to their lightweight and superior properties. Although chain bending stiffness has been recognized to play an essential role in their thermodynamical and mechanical properties, how it influences these properties of cross-linked polymers with flexible or semi-flexible chains remains under debate. Here, we systematically explore its influences utilizing coarse-grained (CG) molecular dynamics (MD) simulations based on a bead-spring CG model. It is found that with chain bending stiffness increasing, both density and elastic moduli (i.e., shear modulus and tensile modulus) of cross-linked polymers first decrease slightly and then decrease significantly followed by a gradual increase, along with the polymer transition from a dense cross-linked thermoset to a highly porous fibrous network. The moduli of cross-linked polymers with flexible and semi-flexible chains exhibit distinct scaling laws with the density. For cross-linked polymers with flexible chains, their moduli increase significantly with increasing strain rate, which correlates to the change in potential energy of interchain interaction during deformation. However, the moduli display slight dependence on strain rate for porous cross-linked polymers with sufficiently stiff chains, where the intrachain interactions (i.e., bond stretching and angle bending energies) become dominant and independent of strain rate. Moreover, the elastic moduli exhibit scaling laws with Debye-Waller factor for both dense cross-linked thermosets with flexible chains and highly porous networks with stiff backbones. Our work facilitates a better understanding for mechanical properties and deformation mechanism of cross-linked polymers with variable chain bending stiffness at molecular level, shedding light on tailoring mechanical properties of cross-linked polymers via chain engineering.</div></div>","PeriodicalId":56247,"journal":{"name":"Extreme Mechanics Letters","volume":"73 ","pages":"Article 102252"},"PeriodicalIF":4.3,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142578256","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}