【新文速递】2024年9月17日复合材料SCI期刊最新文章

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今日更新：Composite Structures 6 篇，Composites Part A: Applied Science and Manufacturing 1 篇

Composite Structures

Buckling optimization of Double-Double (DD) laminates with gradual thickness tapering

Dan Wang, Zhoucheng Su, Sridhar Narayanaswamy, Stephen W.L. Tsai

doi:10.1016/j.compstruct.2024.118568

厚度逐渐变细的双双层(DD)层合板的屈曲优化

Double-double (DD) laminates are promising replacements for conventional Quad laminates in aerospace applications because of their inherent design simplicity and, more importantly, the ease of tapering. However, the thickness thinning due to tapering will significantly increase the risk of buckling failure. In this paper, we proposed an implicit global & local model for thickness tapering optimization of DD laminates to maximize buckling resistance under the given weight constraint or weight reduction under buckling constraints. Firstly, a global model is established for buckling load calculation, with material properties calculated from homogenization of local laminates using the classical laminate theory. Then, nodal repeats of a four-plies DD sub-laminate are chosen as design variables to interpolate the tapered thickness profile. Sensitivities of structural responses are calculated semi-analytically to achieve efficient gradient-based optimization. Tapering spacing constraints between adjacent thicknesses are introduced to mitigate the potential delamination due to the stress concentrations caused by sharp thickness variation at the cost of a reduced optimization effect. Finally, typical numerical examples show that DD laminates with optimal gradual thickness tapering can remarkably increase the structural buckling resistance or the weight reduction.

双双(DD)层压板由于其固有的设计简单，更重要的是易于变细，在航空航天应用中有望取代传统的四层层压板。然而，由于变细导致的厚度变薄将显著增加屈曲破坏的风险。在本文中，我们提出了一个隐式的全局和局部模型来优化DD层压板的厚度变细，以在给定的重量约束下最大化屈曲抗力或在屈曲约束下减少重量。首先，建立了屈曲载荷计算的全局模型，利用经典的层合板理论，从局部层合板的均匀化角度计算材料性能;然后，选择四层DD亚层压板的节点重复次数作为设计变量来插值锥形厚度轮廓。采用半解析方法计算结构响应灵敏度，实现基于梯度的有效优化。引入相邻厚度之间的渐窄间距约束，以减轻由于厚度急剧变化引起的应力集中而导致的潜在分层，但代价是降低了优化效果。最后，通过典型的数值算例表明，采用最优渐变厚度的DD层压板可以显著提高结构的抗屈曲能力或减轻结构的重量。

Multi-scale modeling of damage evolution for particle-filled polymer composites

Tao Shen, Yuxuan Fang, Yujiao Zhang, Jia Lou, Jianke Du

doi:10.1016/j.compstruct.2024.118572

颗粒填充聚合物复合材料损伤演化的多尺度建模

In this study, a multi-scale modeling framework that spans from molecular chains to macroscopic structure was proposed for a typical particle-filled polymer composite (HTPB propellants). The cohesive zone model (CZM) is utilized in the RVE model of HTPB propellants to capture the debonding phenomena at the AP/HTPB interface. For the HTPB matrix, a free energy function based on the Gaussian chain network is employed. To depict the chain scission behavior, the phase fracture (PF) method along with gradient-damage theory is introduced. Subsequently, microscale fracture behavior under uniaxial tensile load was investigated based on the constructed RVE model, and a phenomenological macroscopic damage model was developed correspondingly. In this developed model, two damage factors related to the debonding of AP/HTPB interface and the growth of voids in matrix are introduced respectively. Thus, it can not only predict the macroscopic stress–strain response, but also can give the microscopic damage evolution information. Overall, this multi-scale modeling framework can offer us a deeper insight into the microstructural changes and the resulting macroscopic mechanical behavior of HTPB propellants.

在本研究中，针对典型的颗粒填充聚合物复合材料(HTPB推进剂)提出了从分子链到宏观结构的多尺度建模框架。在HTPB推进剂的RVE模型中采用内聚区模型(CZM)来捕捉AP/HTPB界面的脱粘现象。对于HTPB矩阵，采用基于高斯链网络的自由能函数。为了描述断链行为，引入了相断裂法和梯度损伤理论。随后，基于构建的RVE模型，研究了单轴拉伸载荷作用下的微尺度断裂行为，建立了相应的现象学宏观损伤模型。在该模型中，分别引入了与AP/HTPB界面脱粘和基体空隙生长有关的两个损伤因素。因此，它不仅可以预测宏观应力应变响应，而且可以给出微观损伤演化信息。总的来说，这种多尺度建模框架可以让我们更深入地了解HTPB推进剂的微观结构变化和由此产生的宏观力学行为。

Nanofluid minimum quantity lubrication assisted grinding force model considering anisotropy of SiCf/SiC ceramic matrix composites

Qi Zhang, Ben Wang, Chang Song, Hao Wang, Tianlong Zhu

doi:10.1016/j.compstruct.2024.118577

考虑SiCf/SiC陶瓷基复合材料各向异性的纳米流体最小量润滑辅助磨削力模型

SiCf/SiC ceramic matrix composites with excellent thermal stability, light weight and oxidation resistance have become key components in advanced aircraft engines. Nanofluid minimal quantity lubrication (NMQL) exhibits significant potential in enhancing heat transfer and lubrication efficiency during the grinding process. The technological challenge lies in thoroughly investigating the theoretical variation rule of grinding force, assisted by nanofluid minimal quantity lubrication, and subsequently achieving low-damage machining of SiCf/SiC composites. In this study, a prediction model for the grinding force during NMQL-assisted grinding was established, integrating diverse lubrication methods, grinding wheel geometric parameters, wear degree, process parameters, the anisotropy and damage degree of SiCf/SiC composites. The model was subsequently experimentally validated through grinding tests conducted on SiCf/SiC composites under various conditions, including dry grinding (DG), flood grinding (FG), minimum quantity lubrication (MQL), and carbon nanotube nanofluids (NMQL-CNTs), across multiple grinding depths. The present investigation’s grinding force forecasting model is evidenced to possess high accuracy of precision, showcasing mean deviations of 6.64 % and 11.97 % in the perpendicular (Fn) and tangential (Ft) grinding force components, respectively. Additionally, employing NMQL-CNTs facilitates the achievement of minimal grinding force and surface finish quality. At depths of 0.4 mm and 0.6 mm during grinding, the mean Fn magnitudes under the NMQL-CNTs lubrication approach underwent a decrease of 66.7 % and 74.5 %, respectively, in contrast, the mean Ft magnitudes experienced a reduction of 55 % and 67.2 %, correspondingly, in comparison to the DG lubrication technique. Notwithstanding the consistency in the material’s brittle removal mechanism across varying lubrication strategies, the NMQL-CNTs approach effectively alleviates fiber abrasion. Concisely, the research presented herein provides foundational theoretical insights and practical technological assistance for the achievement of low damage SiCf/SiC composite processing.

SiCf/SiC陶瓷基复合材料具有优异的热稳定性、重量轻、抗氧化性能，已成为先进航空发动机的关键部件。纳米流体最小量润滑(NMQL)在提高磨削过程的传热和润滑效率方面具有显著的潜力。该技术的挑战在于深入研究磨削力的理论变化规律，并辅以纳米流体的微量润滑，从而实现SiCf/SiC复合材料的低损伤加工。在本研究中，综合多种润滑方式、砂轮几何参数、磨损程度、工艺参数、SiCf/SiC复合材料各向异性和损伤程度，建立了nmql辅助磨削磨削力预测模型。随后，对SiCf/SiC复合材料进行了多种条件下的磨削试验，包括干式磨削(DG)、洪式磨削(FG)、最小量润滑(MQL)和碳纳米管纳米流体(NMQL-CNTs)，并在多个磨削深度下对模型进行了实验验证。所建立的磨削力预测模型具有较高的精度，在磨削力垂直分量(Fn)和切向分量(Ft)上的平均偏差分别为6.64 %和11.97 %。此外，采用NMQL-CNTs有助于实现最小的磨削力和表面光洁度质量。在磨削深度为0.4 mm和0.6 mm处，与DG润滑相比，NMQL-CNTs润滑方式下的Fn平均强度分别降低了66.7 %和74.5 %，而Ft平均强度分别降低了55 %和67. %。尽管在不同的润滑策略中材料的脆性去除机制是一致的，但NMQL-CNTs方法有效地减轻了纤维磨损。总之，本文的研究为实现低损伤SiCf/SiC复合材料的加工提供了基础的理论见解和实际的技术支持。

Elasticity solutions for functionally graded beams with arbitrary distributed loads

Changwei Tang, Guansuo Dui, Yuyao Fu

doi:10.1016/j.compstruct.2024.118578

具有任意分布荷载的功能梯度梁的弹性解

This paper derives the exact general elasticity solution for functionally graded rectangular beams subjected to arbitrary normal and tangential loads and with arbitrary end constraints. The general solution consists of bending moments and their integrals and derivatives, along with load-independent function sequences of the longitudinal coordinate. The method for determining function sequences has been established based on the stress function method. General solution formulas for stresses, strains and displacements have been derived and used to solve explicit special solutions for six cases involving concentrated forces, uniformly loads, and quadratically distributed loads with different displacement constraints scenarios. The results obtained are compared with existing exact solutions and those of Euler–Bernoulli and Timoshenko beams, and the errors of the latter two are analysed.

本文导出了在任意法向和切向荷载作用下具有任意端部约束的功能梯度矩形梁的精确一般弹性解。通解包括弯矩及其积分和导数，以及纵坐标的与荷载无关的函数序列。在应力函数法的基础上，建立了确定功能序列的方法。推导了应力、应变和位移的通解公式，并将其用于求解具有不同位移约束的集中力、均匀载荷和二次分布载荷六种情况下的显式特解。将所得结果与已有的精确解以及Euler-Bernoulli和Timoshenko光束的精确解进行了比较，并对后两者的误差进行了分析。

Design-manufacturing-performance of electromagnetic absorbing/load bearing three-dimensional honeycomb woven composites

Wenbin Yao, Xinghai Zhou, Yuan Gao, Yongfang Qian, Lihua Lyu

doi:10.1016/j.compstruct.2024.118581

电磁吸收/承载三维蜂窝编织复合材料的设计制造与性能研究

Structural electromagnetic wave (EMW) absorbing composites play a critical role in both civilian and military applications. However, traditional sandwich honeycomb EMW absorbing composites have poor out-of-plane mechanical properties and load-bearing performance.This study introduces the development of a three-dimensional honeycomb woven composite (3DHWC) that integrates EMW absorption and load-bearing capabilities. A weaving loom was used to fabricate a three-dimensional honeycomb woven structure fabric (3DHSWF) with varying structural parameters. Subsequently, the composites were formed using carbon black (CB), multi-walled carbon nanotubes (MWCNTs), and carbonyl iron powder (CIP) as hybrid absorbers, epoxy resin as the matrix, combined with the vacuum-assisted resin transfer molding (VARTM) process. Testing confirmed the material’s excellent EMW absorption and mechanical properties, achieving a maximum reflection loss (RL) of −30.9 dB and an adequate EMW absorption bandwidth (EAB) of 14.58 GHz. The maximum bending load reached 5799.1 N, with no delamination observed in the samples. This material demonstrates outstanding EMW absorption performance and exhibits superior load-bearing capacity while maintaining structural integrity. Our research provides valuable insights into the design of honeycomb EMW absorbing composites, offering significant advancements in EMW absorption efficiency and bending mechanical properties.

结构电磁波吸波复合材料在民用和军用领域都发挥着重要作用。然而，传统的夹层蜂窝吸波复合材料的面外力学性能和承载性能较差。本研究介绍了一种集EMW吸收和承载能力于一体的三维蜂窝编织复合材料(3DHWC)的开发。利用织布机制备了具有不同结构参数的三维蜂窝结构织物(3DHSWF)。随后，以炭黑(CB)、多壁碳纳米管(MWCNTs)和羰基铁粉(CIP)为杂化吸收剂，环氧树脂为基体，结合真空辅助树脂传递模塑(VARTM)工艺制备复合材料。测试证实该材料具有优异的EMW吸收和机械性能，最大反射损耗(RL)为−30.9 dB, EMW吸收带宽(EAB)为14.58 GHz。最大弯曲载荷达到5799.1 N，样品未出现分层现象。这种材料具有出色的EMW吸收性能，在保持结构完整性的同时具有优越的承载能力。我们的研究为蜂窝吸收EMW复合材料的设计提供了有价值的见解，在EMW吸收效率和弯曲力学性能方面取得了重大进展。

Investigation of the degradation over steel/GFRP single lap joint: UV radiation and immersion at different temperatures

Hiasmim Rohem Gualberto, João Marciano Laredo dos Reis, Mônica Calixto de Andrade, Hector Reynaldo Meneses Costa, Domenio de Souza Faria, Julian David Hunt, Felipe do Carmo Amorim

doi:10.1016/j.compstruct.2024.118590

钢/玻璃钢单搭接接头的降解研究:不同温度下的紫外线辐射和浸渍

Adhesive joints with composite components are used in various fields and under diverse environmental conditions. Exposure to UV radiation, temperature fluctuations, and immersion in different mediums can influence their performance. This study focuses on the degradation of steel/GFRP (glass fiber reinforced polymer) adhesive joints by immersing them in distilled and salt water at three different temperatures (40 °C, room temperature, and 4 °C), with and without prior exposure to UV radiation. Water absorption over time was evaluated under different degradation conditions, studying the absorption of the joints, composite, and adhesive, both individually and in combination. Mechanical shear tests on the joints and three-point bending tests on the composites were conducted, along with an assessment of failure modes influenced by water absorption and UV degradation. The results indicate that immersion temperature affects water absorption, post-curing, and the stiffness of the matrix and polymers, while UV radiation promotes post-curing and facilitates water absorption. The combined degradation conditions exhibit different effects on the materials compared to individual degradation, highlighting the complexity of service environmental conditions.

具有复合构件的粘接接头用于各种领域和各种环境条件。暴露于紫外线辐射、温度波动和浸泡在不同的介质中都会影响它们的性能。本研究的重点是通过将钢/GFRP(玻璃纤维增强聚合物)粘合接头浸泡在三种不同温度(40 °C，室温和4 °C)的蒸馏水和盐水中，并事先暴露在紫外线辐射下和不暴露在紫外线辐射下，来降解钢/GFRP(玻璃纤维增强聚合物)粘合接头。在不同的降解条件下，评估了吸水率随时间的变化，研究了接头、复合材料和粘合剂的吸水率，无论是单独的还是组合的。对接头进行了力学剪切试验，对复合材料进行了三点弯曲试验，并对吸水率和紫外线降解对复合材料破坏模式的影响进行了评估。结果表明，浸没温度影响基体和聚合物的吸水率、后固化率以及刚度，而紫外线辐射促进后固化并促进吸水率。与单独降解相比，复合降解条件对材料的影响不同，凸显了服役环境条件的复杂性。

Composites Part A: Applied Science and Manufacturing

Physics-informed machine learning for loading history dependent fatigue delamination of composite laminates

Liaojun Yao, Jiexiong Wang, Mingyue Chuai, Stepan V. Lomov, V. Carvelli

doi:10.1016/j.compositesa.2024.108474

基于物理的复合材料层合板加载历史疲劳分层的机器学习

Fiber bridging has retardation effect on Mode I fatigue delamination, making the damage loading history dependent. This research creates a physics-informed machine learning (ML) model for characterizing this fatigue delamination propagation. After a training, the model can predict fatigue crack growth rate for a given crack length, accounting for a certain amount of bridging fibers. Mode I fatigue experiments were first performed to obtain sufficient data for the ML. A semi-empirical Paris-type correlation determines fatigue damage evolution with bridging retardation. This correlation was integrated as a physical constraint into the physics-informed neural network (PINN). PINN demonstrates excellent performance: the predictions of the delamination fall within a narrow scatter band of 1.5 times by crack growth rate, outperforming both the non-physics-informed ML model and the Paris-type correlation. The proposed ML model can be applied for the development, characterization and comparison of composite materials, and for composite structure design and life evaluation.

纤维桥接对I型疲劳分层有阻滞作用，使损伤加载历史具有依赖性。本研究创建了一个物理信息的机器学习(ML)模型来表征这种疲劳分层传播。经过训练后，该模型可以预测在给定裂纹长度下，在桥接纤维数量一定的情况下，疲劳裂纹的扩展速率。首先进行了I型疲劳试验，以获得足够的数据。半经验paris型相关性确定了疲劳损伤随桥接延迟的演变。这种相关性作为物理约束集成到物理信息神经网络(PINN)中。PINN表现出优异的性能:分层的预测落在裂缝增长率的1.5倍的窄散射带内，优于非物理信息ML模型和paris型相关。该模型可用于复合材料的开发、表征和比较，以及复合材料的结构设计和寿命评估。

来源：复合材料力学仿真Composites FEM

【新文速递】2024年11月16日固体力学SCI期刊最新文章

今日更新：International Journal of Solids and Structures 1 篇，Journal of the Mechanics and Physics of Solids 2 篇，Thin-Walled Structures 1 篇International Journal of Solids and StructuresMinimum energy combined and separated bounds on elastic constants of transversely-isotropic compositesDuc-Chinh Phamdoi:10.1016/j.ijsolstr.2024.113134横向各向同性复合材料弹性常数的最小能量组合界和分离界The considered linearly-elastic transversely-isotropic composite (TIC) is composed of n isotropic, or more generally, transversely-isotropic components sharing the materials’ common symmetry axis with that of the macroscopic material. Using the basic minimum energy and complementary energy principles with certain free-parameter-dependent mixed-longitudinal-transverse-mode strain and stress trial fields, various combination bounds involving some sets of the macroscopic (effective) mixed-mode elastic constants of the composite, which are inter-connected via the constitutive relations, have been established. Choosing the appropriate parameter values of/or optimizing over the free parameters in those inequalities, the separated bounds on the major effective mixed-transverse-longitudinal-mode elastic constants, including the transverse bulk modulus K_eff, the longitudinal Young modulus E_eff, and the longitudinal Poisson’s ratio ν_eff, are derived, beside the classical arithmetic and harmonic average bounds on the pure-mode ones - the transverse shear (μ_eff) and longitudinal shear (μ`_eff) moduli. The separated bounds on 4 remaining effective mixed-mode elastic constants are also obtained. The illustrative numerical comparisons of the bounds, in the two component case, with those for the special subclass of unidirectional transversely-isotropic composites (UTIC), having the unidirectional cylindrical boundaries between the component materials parallel to their symmetry axis, and the exact coated-cylinder assemblage and laminate models are presented. The extreme models cover substantial parts between the bounds for TIC; however the laminate models lie outside the bounds for the subclass UTIC.考虑的线性弹性横向各向同性复合材料（TIC）由n个各向同性或更一般地，横向各向同性组件组成，这些组件与宏观材料的对称轴共享材料的对称性。利用基本的能量最小化和补充能量原理，以及与某些自由参数相关的混合纵向-横向模式应变和应力试探场，建立了涉及复合材料宏观（有效）混合模式弹性常数的一些集合的组合界限，这些常数通过本构关系相互关联。选择这些不等式中的适当参数值或对自由参数进行优化，除了经典的算术和调和平均纯模式界限（横向剪切模量μ_eff和纵向剪切模量μ`_eff）之外，还得出了分离的纯模式界限，包括横向体模量K_eff、纵向杨氏模量E_eff和纵向泊松比ν_eff。还获得了剩余4个有效混合模量边界的分离解。在两组元情况下，将这些边界与具有平行于对称轴的组元材料的单向圆柱形边界之间的特殊子类各向同性复合材料（UTIC）的边界、精确的涂层圆柱体组合模型和层合模型进行了说明性的数值比较。极端模型覆盖了TIC边界的大部分区域，但层合模型则位于子类UTIC的边界之外。Journal of the Mechanics and Physics of SolidsUnraveling the Molecular Mechanisms of Membrane Rupture: Insights from All-Atom Simulations and Theoretical ModelingPanpan Zhu, Ji Lin, Yimou Fu, Chun Shen, Haofei Zhou, Shaoxing Qu, Huajian Gaodoi:10.1016/j.jmps.2024.105958揭开膜破裂的分子机制：来自全原子模拟和理论建模的见解Cell membrane rupture occurs universally and is long thought to be the terminal event of cell death; however, there is an inadequate understanding of the microscopic mechanisms of membrane rupture at the molecular level. In this study, we investigated the rupture mechanism of two model membranes, 1-palmitoyl-2-oleoyl-phosphatidylcholine (POPC) and cholesterol bilayer membranes, under surface tension by all-atom molecular simulations and theoretical modeling. Under surface tension, the tail chains of POPC molecules become disordered, leading to ductile membrane deformation, while cholesterol membranes display limited deformation before rupture. We analyzed the orientation of tail chains and the internal stresses within the membranes, revealing that the mutual attraction among different tail chains and the resulting stress peak in the tail region of the membrane play substantial roles in the membrane rupture process. Based on these physical insights, we proposed a theoretical model that incorporates an internal variable of tail chain orientation to capture the variations in strain and orientation of different membrane components under varying surface tensions. The critical rupture threshold predicted by our theoretical model aligns well with the simulation results, demonstrating a brittle to ductile transition for membranes with different cholesterol contents. Our study unravels the impact of tail chain orientation and internal stress on membrane mechanics, which deepens the understanding of the microscale mechanisms underlying membrane rupture.细胞膜破裂是普遍存在的，长期以来被认为是细胞死亡的终末事件；然而，在分子水平上对膜破裂的微观机制了解不足。本研究采用全原子分子模拟和理论建模的方法，研究了1-棕榈酰-2-油酰-磷脂酰胆碱（POPC）和胆固醇双层膜在表面张力作用下的破裂机理。在表面张力作用下，POPC分子尾链变得无序，导致韧性膜变形，而胆固醇膜在破裂前表现为有限变形。我们分析了尾链的取向和膜内的内应力，揭示了不同尾链之间的相互吸引以及在膜尾部区域产生的应力峰值在膜破裂过程中起着重要作用。基于这些物理见解，我们提出了一个理论模型，该模型包含尾链取向的内部变量，以捕捉不同表面张力下不同膜组分的应变和取向变化。我们的理论模型预测的临界破裂阈值与模拟结果很好地吻合，表明具有不同胆固醇含量的膜具有脆性到延性的转变。我们的研究揭示了尾链取向和内应力对膜力学的影响，加深了对膜破裂微观机制的理解。Mechanics of electroadhesion of polyelectrolyte hydrogel heterojunctions enabled by ionic double layersZheyu Dong, Zhi Sheng, Zihang Shen, Shaoxing Qu, Zheng Jiadoi:10.1016/j.jmps.2024.105960离子双层驱动的聚电解质水凝胶异质结电粘附力学In recent years, soft materials with reversible adhesion have come to the fore as a promising avenue of research. Compared to other reversible adhesion methods, electroadhesion enabled by the formation of ionic double layer (IDL) has been widely used due to its simplicity, low energy consumption, fast response, and reversibility. Despite the extensive experimental studies and qualitative mechanistic explanations, there remains a dearth of theoretical studies on this topic, particularly regarding the development of theoretical mechanics models. Our study aims to address this gap by establishing a mechanics model of IDL-enabled electroadhesion between soft materials. We specifically focus on modeling the low-voltage electroadhesion of heterojunctions between two polyelectrolyte hydrogels. The model decomposes the electroadhesion formation into two successive physical processes. First, under appropriate bias conditions, the applied voltage drives the mobile ions in each polyelectrolyte hydrogel to migrate toward the electrode, resulting in the formation of an IDL at the heterojunction interface and the generation of a potent built-in electric field inside the IDL. Second, driven by the strong built-in electric field of IDL, the dangling charged chains of the two polyelectrolyte hydrogels begin to cross the heterojunction interface and penetrate into the opposite hydrogel matrix to form ionic bonds with the oppositely-charged chains, resulting in a bridging network that sutures the interface. As a result, the electrostatic interactions inside the IDL as well as the bridging network across the interface leads to the electroadhesion of polyelectrolyte hydrogel heterojunctions. The modeling results show that the IDL thickness, the IDL electric field density, and the electroadhesion strength increase with the applied voltage. We also experimentally conduct the electroadhesion tests, and the measurements of electroadhesion strength quantitatively match the modeling results well. For the first time, we reveal the underlying mechanism of IDL-driven electroadhesion by establishing a theoretical mechanics model. We anticipate that our mechanics model can shed light on the design, optimization, and control of the electroadhesion of soft-material heterojunctions.近年来，具有可逆性粘附的软质材料作为一种很有前途的研究方向而崭露头角。与其他可逆粘附方法相比，离子双层电粘附（IDL）具有简单、低能耗、响应快、可逆性等优点，得到了广泛的应用。尽管有大量的实验研究和定性的力学解释，但关于这一主题的理论研究仍然缺乏，特别是关于理论力学模型的发展。我们的研究旨在通过建立软材料之间idl驱动的电粘附的力学模型来解决这一差距。我们特别专注于模拟两种聚电解质水凝胶之间异质结的低压电粘附。该模型将电粘附的形成分解为两个连续的物理过程。首先，在适当的偏置条件下，施加的电压驱动每个聚电解质水凝胶中的可移动离子向电极迁移，导致在异质结界面处形成IDL，并在IDL内部产生强大的内置电场。其次，在IDL强大的内置电场的驱动下，两种聚电解质水凝胶的悬空带电链开始穿过异质结界面，并渗透到相反的水凝胶基质中，与相反的带电链形成离子键，形成桥接网络，将界面连接起来。因此，IDL内部的静电相互作用以及界面上的桥接网络导致了聚电解质水凝胶异质结的电粘附。模拟结果表明，随着施加电压的增加，IDL厚度、IDL电场密度和电粘附强度均增加。我们还进行了电粘附实验，电粘附强度的测量结果与模型结果吻合较好。我们首次通过建立理论力学模型揭示了idl驱动电粘附的潜在机制。我们期望我们的力学模型可以为软材料异质结的电粘附设计、优化和控制提供启示。Thin-Walled StructuresEffect of fractal dimension on mechanical behaviour and energy absorption of Menger sponge-inspired fractal structuresMadhusha Bogahawaththa, Damith Mohotti, Paul J. Hazell, Hongxu Wang, Kasun Wijesooriya, Chi King Leedoi:10.1016/j.tws.2024.112704分形维数对Menger海绵状分形结构力学性能和吸能的影响The Fractal Dimension (FD) of Menger Fractal Cubes (MFCs) defines their intricate geometry, making them ideal for lightweight structural applications. However, the effect of FD on their structural behaviour is largely unexplored. This study examines AlSi7Mg MFC geometries formed through a recursive process, with densities ranging from 40 to 1958 kg/m³, corresponding to FDs ranging from 2.35 to 2.73. Compression tests and simulations revealed that higher fractal orders increased densification displacement, achieving up to 80% compressibility, with multi-level extended plateau regions indicating enhanced energy absorption. The fourth-order MFC with an FD of 2.35 and a density of 40 kg/m³ showed a specific energy absorption (SEA) of 6 J/g, demonstrating its potential for weight-efficient, energy-absorbing structures. The outcomes of this study indicate that total energy absorbed increases with an increasing FD, while crush efficiency improves as FD decreases showing better crashworthiness. Moreover, the structures exhibited unique force-displacement responses tailored to their FD. These findings offer valuable insights into optimising thin-walled fractal structures for various engineering applications by adjusting the FD to fine-tune relative density and enhance mechanical performance.门格尔分形立方体（mfc）的分形维数（FD）定义了它们复杂的几何形状，使它们成为轻量化结构应用的理想选择。然而，FD对其结构行为的影响在很大程度上尚未被探索。本研究考察了通过递归过程形成的AlSi7Mg MFC几何形状，其密度范围为40至1958 kg/m³，对应的fd范围为2.35至2.73。压缩试验和模拟表明，更高的分形阶数增加了致密化位移，可达到80%的压缩率，多层次扩展的高原区域表明能量吸收增强。四阶MFC的FD为2.35，密度为40 kg/m³，比能吸收（SEA）为6 J/g，显示了其作为减重吸能结构的潜力。研究结果表明，总能量吸收随FD的增加而增加，粉碎效率随FD的减小而提高，具有较好的耐撞性。此外，结构表现出与其FD相适应的独特的力-位移响应。这些发现为优化各种工程应用的薄壁分形结构提供了有价值的见解，通过调整FD来微调相对密度并提高机械性能。来源：复合材料力学仿真Composites FEM