Extreme Mechanics Letters最新文献_第3页

Understanding the role of chain stiffness in the mechanical response of cross-linked polymer: Flexible vs. semi-flexible chains 了解链刚度在交联聚合物机械响应中的作用：柔性链与半柔性链

IF 4.3 3区工程技术 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Extreme Mechanics Letters

Pub Date : 2024-10-24 DOI: 10.1016/j.eml.2024.102252

Xiangrui Zheng , Wenjie Xia , Yao Zhang

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.

交联聚合物由于重量轻、性能优越而被广泛应用于结构、工程和生物医学领域。虽然人们已经认识到链弯曲刚度在其热力学和机械性能中起着至关重要的作用，但它如何影响具有柔性或半柔性链的交联聚合物的这些性能仍存在争议。在此，我们利用基于珠链 CG 模型的粗粒度（CG）分子动力学（MD）模拟，系统地探讨了其影响因素。结果发现，随着链弯曲刚度的增加，交联聚合物的密度和弹性模量（即剪切模量和拉伸模量）先是略有下降，然后显著下降，接着逐渐增加，聚合物也从致密交联热固性过渡到高多孔性纤维网络。具有柔性链和半柔性链的交联聚合物的模量随密度的变化呈现出不同的缩放规律。对于具有柔性链的交联聚合物，其模量随着应变速率的增加而显著增加，这与变形过程中链间相互作用势能的变化有关。然而，对于具有足够刚性链的多孔交联聚合物，模量对应变速率的依赖性很小，链内相互作用（即键拉伸能和角弯曲能）成为主导，与应变速率无关。此外，对于具有柔性链的致密交联热固性塑料和具有刚性骨架的高孔隙网络，弹性模量都呈现出与 Debye-Waller 因子成比例的规律。我们的研究工作有助于更好地理解具有可变链弯曲刚度的交联聚合物在分子水平上的机械性能和变形机制，为通过链工程定制交联聚合物的机械性能提供了启示。

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引用次数: 0

Linear strain gradient-regulated bifurcation of circular bilayer plates 圆双层板的线性应变梯度调节分叉

IF 4.3 3区工程技术 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Extreme Mechanics Letters

Pub Date : 2024-10-22 DOI: 10.1016/j.eml.2024.102250

Ben Cao , Yuanhang Yang , Mingchao Liu , Changjin Huang

Bilayer structures with controllable self-folding capability have found applications in a variety of cutting-edge fields such as flexible electrics, wearable devices and soft robotics. The folding of bilayer structures occurs when the mismatch strain between the two layers exceeds the bifurcation threshold, resulting in a deformation transition from an axisymmetric to a folded state. Previous efforts have predominantly focused on bilayer structures with uniform and/or anisotropic strain distributions. However, the role of non-uniform in-plane strain distributions in regulating the bifurcation of bilayer structures has not been fully understood. In this study, the effects of linear in-plane strain gradients on the bifurcation of circular bilayer plates, both with and without geometric mismatch, are systematically investigated by combining theoretical analysis, finite element simulations and experiments. Our results reveal that both the mismatch strain gradient and the geometric mismatch between the two layers play crucial roles in regulating bifurcation. Notably, linear mismatch strain gradients with larger strain at the center delay bifurcation, while those with larger strain along the edge promote bifurcation. This work offers new insights into the design of controllable self-folding bilayer structures, which is of great significance for advanced applications.

具有可控自折叠能力的双层结构已在柔性电气、可穿戴设备和软机器人等多个尖端领域得到应用。双层结构的折叠发生在两层之间的错配应变超过分叉阈值时，从而导致从轴对称状态到折叠状态的变形过渡。以往的研究主要集中于均匀和/或各向异性应变分布的双层结构。然而，非均匀面内应变分布在调节双层结构分叉中的作用尚未得到充分了解。在本研究中，我们结合理论分析、有限元模拟和实验，系统地研究了线性面内应变梯度对有几何错配和无几何错配的圆形双层板分叉的影响。研究结果表明，错配应变梯度和两层板之间的几何错配在分叉过程中起着至关重要的调节作用。值得注意的是，中心应变较大的线性错配应变梯度会延迟分叉，而边缘应变较大的线性错配应变梯度则会促进分叉。这项研究为设计可控自折叠双层结构提供了新的见解，对先进应用具有重要意义。

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引用次数: 0

Multifunctional bistable ultrathin composite booms with flexible electronics 带柔性电子器件的多功能双稳态超薄复合材料吊杆

IF 4.3 3区工程技术 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Extreme Mechanics Letters

Pub Date : 2024-10-18 DOI: 10.1016/j.eml.2024.102247

Yao Yao , Juan M. Fernandez , Sven G. Bilén , Xin Ning

Small satellites such as CubeSats pose demanding requirements on the weight, size, and multifunctionality of their structures due to extreme constraints on the payload mass and volume. To address this challenge, we introduce a concept of multifunctional deployable space structures for CubeSats based on ultrathin, elastically foldable, and self-deployable bistable composite structures integrated with flexible electronics. The multifunctional bistable booms can be stored in a coiled configuration and self-deploy into a long structure upon initiation by releasing the stored strain energy. The boom demonstrates the capabilities of delivering power and transmitting data from the CubeSat to the flexible devices on the boom tip. The boom also shows the ability to monitor the dynamics and vibration during and after the deployment. A payload boom has been installed in a 3 U CubeSat as flight hardware for in-space testing and demonstration. This effort combines morphable ultrathin composite structures with flexible electronics.

由于有效载荷的质量和体积受到极大限制，立方体卫星等小型卫星对其结构的重量、尺寸和多功能性提出了苛刻的要求。为了应对这一挑战，我们提出了一种用于立方体卫星的多功能可部署空间结构概念，这种结构基于超薄、可弹性折叠和可自行部署的双稳态复合结构，并集成了柔性电子器件。多功能双稳态吊杆可以盘绕配置存储，并在启动时通过释放存储的应变能自展开成一个长结构。该吊杆展示了从立方体卫星向吊杆顶端的柔性设备供电和传输数据的能力。吊杆还展示了在部署期间和之后监测动态和振动的能力。有效载荷吊杆已作为飞行硬件安装在 3 U 立方体卫星上，用于空间测试和演示。这项工作将可变形的超薄复合材料结构与柔性电子设备相结合。

引用次数: 0

Strength characterization of ultrathin chips by using large deflection theory of multi-layer plate for three-point bending tests 利用多层板大挠度理论进行超薄芯片三点弯曲试验的强度表征

IF 4.3 3区工程技术 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Extreme Mechanics Letters

Pub Date : 2024-10-17 DOI: 10.1016/j.eml.2024.102249

Dao-Long Chen , Chien-Ming Chen , Chin-I. Tsai , Ryan Chen , Hsin-Chih Shih , Ian Hu , Sheng-Rui Jian

This study developed mathematical formulas for a two-layer structure, specifically an ultrathin memory die with a film, which accounted for large deflection effects with Legendre-Jacobi’s elliptic integrals and frictional forces on the supports. The formulas were used to calculate die strength using three-point bending tests and were verified through comparisons with simulated and measured load-deflection curves. The study found that the Poisson's effect cannot be neglected for plate-like structures, and the slip effect was also significant, with accounting for friction improving accuracy. Additionally, the span between supports was found to increase nonlinearity. The study concluded that stress-deflection curves derived in the study can be used to determine die strength, with calculated strengths of 745 MPa and 1296 MPa for film-up and film-down configurations, respectively.

本研究开发了双层结构的数学公式，特别是带有薄膜的超薄记忆模具，利用 Legendre-Jacobi 的椭圆积分和支撑物上的摩擦力考虑了大挠度效应。这些公式用于通过三点弯曲试验计算模具强度，并通过与模拟和测量的载荷-挠度曲线进行比较进行验证。研究发现，对于板状结构，泊松效应不可忽视，滑移效应也很重要，考虑摩擦力可提高精度。此外，研究还发现支撑之间的跨度会增加非线性。研究得出的结论是，研究中得出的应力-挠度曲线可用于确定模具强度，薄膜向上和薄膜向下配置的计算强度分别为 745 兆帕和 1296 兆帕。

引用次数: 0

Optical penetration depth and periodic motion of a photomechanical strip 光电机械带的光学穿透深度和周期性运动

IF 4.3 3区工程技术 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Extreme Mechanics Letters

Pub Date : 2024-10-17 DOI: 10.1016/j.eml.2024.102244

Neda Maghsoodi , Kaushik Bhattacharya

Liquid crystal elastomers (LCEs) containing light-sensitive molecules exhibit large, reversible deformations when subjected to illumination. Here, we investigate the role of optical penetration depth on this photomechanical response. We present a model of the photomechanical behavior of photoactive LCE strips under illumination that goes beyond the common assumption of shallow penetration. This model reveals how the optical penetration depth and the consequent photomechanically induced deformation can depend on the concentration of photoactive molecules, their absorption cross-sections, and the intensity of illumination. Through a series of examples, we show that the penetration depth can quantitatively and qualitatively affect the photomechanical response of a strip. Shallow illumination leads to monotone curvature change while deep penetration can lead to non-monotone response with illumination duration. Further, the flapping behavior (a cyclic wave-like motion) of doubly clamped and buckled strips that has been proposed for locomotion can reverse direction with sufficiently large penetration depth. This opens the possibility of creating wireless light-driven photomechanical actuators and swimmers whose direction of motion can be controlled by light intensity and frequency.

含有光敏分子的液晶弹性体（LCE）在受到光照时会产生巨大的可逆变形。在此，我们研究了光穿透深度对这种光机械响应的作用。我们提出了光活性 LCE 带在光照下的光机械行为模型，该模型超越了浅穿透的常见假设。该模型揭示了光穿透深度以及由此引起的光机械变形如何取决于光活性分子的浓度、吸收截面和光照强度。通过一系列实例，我们表明穿透深度会对带材的光机械响应产生定量和定性影响。较浅的光照会导致单调的曲率变化，而较深的穿透则会随着光照时间的延长导致非单调的响应。此外，双夹紧和屈曲条带的拍打行为（循环波状运动）已被提出用于运动，在足够大的穿透深度下，这种拍打行为可以逆转方向。这为制造无线光驱动光机械致动器和游泳器提供了可能性，其运动方向可由光照强度和频率控制。

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引用次数: 0

Interfacial fatigue fracture of pressure sensitive adhesives 压敏粘合剂的界面疲劳断裂

IF 4.3 3区工程技术 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Extreme Mechanics Letters

Pub Date : 2024-10-16 DOI: 10.1016/j.eml.2024.102248

Yichen Wan , Qianfeng Yin , Ping Zhang , Canhui Yang , Ruobing Bai

Pressure sensitive adhesives (PSAs) are viscoelastic polymers that can form fast and robust adhesion with various adherends under fingertip pressure. The rapidly expanding application domain of PSAs, such as healthcare, wearable electronics, and flexible displays, requires PSAs to sustain prolonged loads throughout their lifetime, calling for fundamental studies on their fatigue behaviors. However, fatigue of PSAs has remained poorly investigated. Here we study interfacial fatigue fracture of PSAs, focusing on the cyclic interfacial crack propagation due to the gradual rupture of noncovalent bonds between a PSA and an adherend. We fabricate a model PSA made of a hysteresis-free poly(butyl acrylate) bulk elastomer dip-coated with a viscoelastic poly(butyl acrylate-co-isobornyl acrylate) sticky surface, both crosslinked by poly(ethylene glycol) diacrylate. We adhere the fabricated PSA to a polyester strip to form a bilayer. The bilayer is covered by another polyester film as an inextensible backing layer. Using cyclic and monotonic peeling tests, we characterize the interfacial fatigue and fracture behaviors of the bilayer. From the experimental data, we obtain the interfacial fatigue threshold (4.6 J/m²) under cyclic peeling, the slow crack threshold (33.9 J/m²) under monotonic peeling, and the adhesion toughness (∼ 400 J/m²) at a finite peeling speed. We develop a modified Lake-Thomas model to describe the interfacial fatigue threshold due to noncovalent bond breaking. The theoretical prediction (2.6 J/m²) agrees well with the experimental measurement (4.6 J/m²). Finally, we discuss possible additional dissipation mechanisms involved in the larger slow crack threshold and much larger adhesion toughness. It is hoped that this study will provide new fundamental knowledge for fracture mechanics of PSAs, as well as guidance for future tough and durable PSAs.

压敏胶（PSA）是一种粘弹性聚合物，可在指尖压力下与各种粘合剂形成快速而牢固的粘合。压敏胶的应用领域正在迅速扩大，如医疗保健、可穿戴电子设备和柔性显示器等，这就要求压敏胶在其整个使用寿命期间承受长时间的负载，从而要求对其疲劳行为进行基础研究。然而，对聚苯乙烯泡沫塑料疲劳的研究仍然很少。在此，我们研究了 PSA 的界面疲劳断裂，重点是 PSA 和粘合剂之间的非共价键逐渐断裂导致的周期性界面裂纹扩展。我们制作了一个模型 PSA，它由无滞后聚（丙烯酸丁酯）块状弹性体和粘弹性聚（丙烯酸丁酯-丙烯酸异冰片酯）粘性表面浸涂而成，两者均由聚（乙二醇）二丙烯酸酯交联。我们将制作好的 PSA 粘贴到聚酯条上，形成一个双层。双分子层由另一层聚酯薄膜覆盖，作为不可延伸的背层。通过循环和单调剥离试验，我们确定了双层膜的界面疲劳和断裂行为特征。根据实验数据，我们得到了循环剥离下的界面疲劳阈值（4.6 J/m2）、单调剥离下的慢速裂纹阈值（33.9 J/m2）以及有限剥离速度下的粘附韧性（∼ 400 J/m2）。我们建立了一个改进的 Lake-Thomas 模型来描述非共价键断裂导致的界面疲劳阈值。理论预测值（2.6 J/m2）与实验测量值（4.6 J/m2）非常吻合。最后，我们讨论了更大的慢速裂纹阈值和更大的粘附韧性可能涉及的其他耗散机制。希望本研究能为 PSAs 断裂力学提供新的基础知识，并为未来坚韧耐用的 PSAs 提供指导。

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引用次数: 0

Orientation-dependent deformation and failure of micropillar shape memory ceramics: A 3D phase-field study 微柱形状记忆陶瓷的定向变形和失效：三维相场研究

IF 4.3 3区工程技术 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Extreme Mechanics Letters

Pub Date : 2024-10-11 DOI: 10.1016/j.eml.2024.102245

Amirreza Lotfolahpour, Mohsen Asle Zaeem

Some microscopic samples of zirconia-based shape memory ceramics (SMCs) have shown full martensitic phase transformation (MPT) over multiple loading cycles without cracking. However, the occurrence of MPT is strongly influenced by grain orientation. Depending on the specific grain orientation relative to the loading direction, alternative mechanisms such as plastic slip and fracture may emerge. This study introduces a phase-field (PF) based framework that integrates a PF-MPT model, a PF fracture model, and a crystal viscoplasticity model to investigate the effects of grain orientation on MPT, plastic slip, and fracture mechanisms in SMC micropillars. Single crystal micropillars are created to distinguish the orientations that facilitate each mechanism. A wide range of grain orientations are found to predominantly exhibit MPT. Micropillars with grain orientations close to the (100) and (001) directions primarily experience fracture, with minimal plastic slip. Additionally, samples oriented along the (110) direction show a significant amount of plastic slip. A pole figure is constructed to elucidate the interplay between MPT, cracking, and plastic slip under compressive loading conditions. This research provides valuable insights into the intricate behavior of SMCs under different loading scenarios, crucial for optimizing their performance in practical applications.

一些氧化锆基形状记忆陶瓷（SMC）的微观样品在多次加载循环中显示出完全的马氏体相变（MPT），而不会产生裂纹。然而，马氏体相变的发生受晶粒取向的影响很大。根据相对于加载方向的特定晶粒取向，可能会出现塑性滑移和断裂等替代机制。本研究引入了一个基于相场（PF）的框架，该框架集成了 PF-MPT 模型、PF 断裂模型和晶体粘弹性模型，用于研究晶粒取向对 SMC 微柱中 MPT、塑性滑移和断裂机制的影响。创建单晶体微柱是为了区分有利于每种机制的取向。结果发现各种晶粒取向都主要表现出 MPT。晶粒取向接近（100）和（001）方向的微柱主要经历断裂，塑性滑移最小。此外，沿（110）方向取向的样品会出现大量塑性滑移。我们构建了一个极点图，以阐明在压缩加载条件下 MPT、开裂和塑性滑移之间的相互作用。这项研究为了解 SMC 在不同加载情况下的复杂行为提供了宝贵的见解，对优化其实际应用性能至关重要。

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引用次数: 0

Hopping potential wells and gait switching in a fish-like robot with a bistable tail 双稳态尾巴鱼形机器人的跳跃势阱和步态切换

IF 4.3 3区工程技术 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Extreme Mechanics Letters

Pub Date : 2024-10-11 DOI: 10.1016/j.eml.2024.102239

Prashanth Chivkula, Colin Rodwell, Phanindra Tallapragada

Fish outperform current underwater robots in speed, agility, and efficiency of locomotion, in part due to their flexible appendages that are capable of rich combinations of modes of motion. In fish-like robots, actuating many different modes of oscillation of tails or fins can become a challenge. This paper presents a highly underactuated (with a single actuator) fish-like robot with a bistable tail that features a double-well elastic potential. Oscillations of such a tail depend on the frequency and amplitude of excitation, and tuning the frequency–amplitude can produce controllable oscillations in different modes leading to different gaits of the robot. This robot design is inspired by recent work on underactuated flexible swimming robots driven by a single rotor. The oscillations of the rotor can propel and steer the robot, but saturation of the rotor makes performing long turns challenging. This paper demonstrates that by adding geometric bistability to the flexible tail, turns can be performed by controllably exciting single-well oscillations in the tail, while exciting double-well oscillations of the tail produces average straight-line motion. The findings of this paper go beyond the application to a narrow class of fish-like robots. More broadly we have demonstrated the use of periodic excitation to produce bistable response that generate different gaits including a steering gait. The mechanics demonstrated here show the feasibility of applications to other mobile soft robots.

鱼类在速度、灵活性和运动效率方面都优于目前的水下机器人，部分原因是它们灵活的附肢能够实现丰富的运动模式组合。在类鱼机器人中，驱动尾巴或鳍的多种不同摆动模式是一项挑战。本文介绍了一种具有双稳态尾部的高度欠驱动（单驱动）仿鱼机器人，其尾部具有双井弹性势能。这种鱼尾的振荡取决于激励的频率和振幅，调整频率和振幅可以产生不同模式的可控振荡，从而导致机器人的不同步态。这种机器人的设计灵感来自于最近关于由单个转子驱动的欠驱动柔性游泳机器人的研究。转子的振荡可以推动机器人并使其转向，但转子的饱和使得进行长距离转弯具有挑战性。本文证明，通过在柔性尾部添加几何双稳态，可以通过可控地激励尾部的单孔振荡来实现转弯，而激励尾部的双孔振荡则可以产生平均直线运动。本文的研究成果不仅适用于狭义的鱼形机器人。更广泛地说，我们已经展示了利用周期性激励产生双稳态响应，从而产生包括转向步态在内的不同步态。本文所展示的力学原理表明了应用于其他移动软体机器人的可行性。

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引用次数: 0

HyperCAN: Hypernetwork-driven deep parameterized constitutive models for metamaterials HyperCAN：超网络驱动的超材料深度参数化构成模型

IF 4.3 3区工程技术 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Extreme Mechanics Letters

Pub Date : 2024-10-11 DOI: 10.1016/j.eml.2024.102243

Li Zheng , Dennis M. Kochmann , Siddhant Kumar

We introduce HyperCAN, a machine learning framework that utilizes hypernetworks to construct adaptable constitutive artificial neural networks for a wide range of beam-based metamaterials exhibiting diverse mechanical behavior under finite deformations. HyperCAN integrates an input convex neural network that models the nonlinear stress–strain map of a truss lattice, while ensuring adherence to fundamental mechanics principles, along with a hypernetwork that dynamically adjusts the parameters of the convex network as a function of the lattice topology and geometry. This unified framework demonstrates robust generalization in predicting the mechanical behavior of previously unseen metamaterial designs and loading scenarios well beyond the training domain. We show how HyperCAN can be integrated into multiscale simulations to accurately capture the highly nonlinear responses of large-scale truss metamaterials, closely matching fully resolved simulations while significantly reducing computational costs. This offers new efficient opportunities for the multiscale design and optimization of truss metamaterials.

我们介绍的 HyperCAN 是一种机器学习框架，它利用超网络为各种基于梁的超材料构建适应性强的构成人工神经网络，这些超材料在有限变形条件下表现出不同的力学行为。HyperCAN 集成了一个输入凸神经网络和一个超网络，前者对桁架晶格的非线性应力应变图进行建模，同时确保遵循基本力学原理，后者可根据晶格拓扑结构和几何形状动态调整凸网络的参数。这个统一的框架在预测以前未曾见过的超材料设计和加载场景的力学行为方面表现出了强大的通用性，远远超出了训练领域。我们展示了如何将 HyperCAN 集成到多尺度模拟中，以准确捕捉大规模桁架超材料的高度非线性响应，从而与全解析模拟紧密匹配，同时显著降低计算成本。这为桁架超材料的多尺度设计和优化提供了新的高效机会。

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引用次数: 0

Electrothermally actuated network metamaterials with reconfigurable bending deformation modes 具有可重构弯曲变形模式的电热致动网络超材料

IF 4.3 3区工程技术 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Extreme Mechanics Letters

Pub Date : 2024-10-10 DOI: 10.1016/j.eml.2024.102241

Kai Zhang , Jinyu Ji , Xiao Kang , Xiaogang Guo

Reconfigurable metamaterials with specific deformation modes show great promise in applications such as multifunctional antenna, stretchable electronic device, and reconfigurable soft robot, due to their ability to achieve multiple operational states within a single system. Previous researches on active metamaterials with bending deformation responses revealed two main issues: (1) achieving reconfigurable deformation within the same metamaterial is challenging due to the reliance on uniform external field actuation; and (2) there is a lack of in-depth studies on the microstructure-property relationships for the bending deformation responses of network metamaterials due to the lack of theoretical analysis. To address these issues, this study presents a mechanical design strategy for an electrothermally actuated network metamaterials to realize reconfigurable bending deformation. A theoretical model describing the electrothermally actuated bending deformation responses is developed through a three-level analysis, which offers a comprehensive understanding of the parameter-property relationships and accurately describes the bending deformation behaviors. The validity of these mechanical models is confirmed through finite element analyses (FEAs) and experimental results. These mechanical models provide analytical solutions for crucial mechanical quantities, including the electrothermally actuated bending angles and effective strains for bending deformation responses. The bending behaviors of the reconfigurable metamaterials under electrothermal actuation can be adjusted by the key nondimensional geometric parameters and the actuation strategies. Additionally, experimental results and FE calculations demonstrate that multiple bending responses can be realized within a single metamaterial by different actuation strategies. This study offers comprehensive guideline from theoretical predictions, FE calculations, and experimental demonstrations for future researched of reconfigurable metamaterials to realize required deformation behaviors.

具有特定变形模式的可重构超材料由于能够在单个系统内实现多种工作状态，因此在多功能天线、可拉伸电子器件和可重构软机器人等应用领域大有可为。以往对具有弯曲变形响应的有源超材料的研究发现了两个主要问题：（1）由于依赖于均匀的外部场致动，在同一超材料内实现可重构变形具有挑战性；（2）由于缺乏理论分析，对网络超材料弯曲变形响应的微结构-属性关系缺乏深入研究。针对这些问题，本研究提出了一种电热致动网络超材料的力学设计策略，以实现可重构的弯曲变形。通过三层分析，建立了一个描述电热致动弯曲变形响应的理论模型，该模型提供了对参数-属性关系的全面理解，并准确地描述了弯曲变形行为。这些机械模型的有效性通过有限元分析和实验结果得到了证实。这些机械模型提供了关键机械量的分析解决方案，包括电热致动弯曲角度和弯曲变形响应的有效应变。可重构超材料在电热致动下的弯曲行为可通过关键的非尺寸几何参数和致动策略进行调整。此外，实验结果和有限元计算证明，通过不同的致动策略，可以在单一超材料中实现多种弯曲响应。本研究从理论预测、有限元计算和实验演示等方面为未来研究可重构超材料提供了全面指导，以实现所需的变形行为。

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引用次数: 0