【新文速递】2023年11月3日固体力学SCI期刊最新文章

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今日更新：International Journal of Solids and Structures 3 篇，Mechanics of Materials 1 篇，Thin-Walled Structures 1 篇

International Journal of Solids and Structures

Thin shells reinforced by fibers with intrinsic flexural and torsional elasticity

Steigmann David J., Bîrsan Mircea, Shirani Milad

doi:10.1016/j.ijsolstr.2023.112550

具有内在弯曲和扭转弹性的纤维增强薄壳

A two-dimensional thin shell model, derived from a three-dimensional Cosserat elasticity theory for fiber-reinforced solids, is presented. Models for single laminae and two-ply laminates are derived. The novelty of these models lies in the assignment of intrinsic flexural and torsional elasticity to the embedded fibers, regarded as continuously distributed material curves.

介绍了一种二维薄壳模型，该模型源自纤维增强固体的三维 Cosserat 弹性理论。推导出了单层板和双层板的模型。这些模型的新颖之处在于将固有的弯曲和扭转弹性分配给嵌入的纤维，并将其视为连续分布的材料曲线。

A novel computational multi-scale modeling of randomly-distributed-graphene/epoxy nanocompfvosites with interfacial interactions

ÇALIŞKAN Umut, GULSEN Hilal

doi:10.1016/j.ijsolstr.2023.112553

具有界面相互作用的随机分布石墨烯/环氧纳米复合材料的新型多尺度计算模型

This article introduces a novel multi-scale modeling methodology that incorporates randomly distributed graphene/epoxy nanocomposites, accounting for interfacial interactions. The objective is to forecast the elastic characteristics and mechanical performance of nanocomposites reinforced with single-layer graphene. We developed a new multi-scale scheme by randomly distributing the triple-structure formed by graphene, interface material and their Van Der Walls interactions in epoxy with an improved algorithm by using the finite element method. The number of single-layer graphene affecting the random distribution method and the volume fraction of nanocomposites were investigated. A developed methodology was proposed for producing graphene-VanDerWalls interactions-interface structures, avoiding overlapping desired geometric dimensions and numbers in a representative control volume and determining random positions. In order to model Van Der Walls interactions between graphene and interface material atoms by finite element method and to apply them to randomly distributed graphene, a different algorithm was required. Performing numerical analyzes of graphene nanoparticles by embedding them into epoxy with the real dimensions is not an appropriate task today. In particular, it is impossible to analyze these real graphene nanoparticles as multiple by randomly distributing them in epoxy. Therefore, in this research, a new approach has been developed to overcome this problem. The result of the model is in acceptable agreement with the result of conducted experimental results from the literature.

本文介绍了一种新颖的多尺度建模方法，其中包含随机分布的石墨烯/环氧纳米复合材料，并考虑了界面相互作用。目的是预测用单层石墨烯增强的纳米复合材料的弹性特性和机械性能。我们开发了一种新的多尺度方案，将石墨烯、界面材料及其范德瓦斯相互作用形成的三重结构随机分布在环氧树脂中，并使用有限元法改进了算法。研究了影响随机分布方法的单层石墨烯数量和纳米复合材料的体积分数。提出了一种用于制造石墨烯-范德瓦尔斯相互作用界面结构的方法，避免在代表性控制体积中重叠所需的几何尺寸和数量，并确定随机位置。为了用有限元法模拟石墨烯与界面材料原子之间的范德瓦尔斯相互作用，并将其应用于随机分布的石墨烯，需要一种不同的算法。通过将石墨烯纳米颗粒嵌入具有实际尺寸的环氧树脂中来对其进行数值分析并不是一项合适的任务。特别是，将这些真实的石墨烯纳米粒子随机分布在环氧树脂中，不可能对其进行多重分析。因此，本研究开发了一种新方法来克服这一问题。该模型的结果与文献中的实验结果一致。

Edge effect and indentation depth-dependent contact behavior in contact of an elastic quarter-space

Li Qiang

doi:10.1016/j.ijsolstr.2023.112552

弹性四分之一空间接触中的边缘效应和随压痕深度变化的接触行为

The edge effect in contact of an elastic quarter-space is numerically studied in this work. The extension of Hetényi’s approach of overlapping two elastic half-spaces is implemented in the boundary element method to obtain the solution of an elastic quarter-space whose top and side surfaces could be both loaded. In the study on the indentation test of a rigid sphere on an elastic quarter-space, the dependencies of the normal force, mean contact radius, and pressure distribution in contact area as well as the internal von Mises stress in relation to the position of the sphere from the side edge are obtained numerically and expressed by fitting the numerical results. These equations can be also used to interpret the indentation depth-dependent contact behavior: from Hertzian contact at the beginning of the indentation to the non-circular contact at large indentation depth. In addition, the results are compared with a contact case of a quarter-space in which the side surface of the quarter-space is not completely free: shear stresses on the side surface vanish but normal stress exists. The latter case generates very similar results, especially the contact area, but its solutions are much easier to achieve by applying a symmetrical loading on an elastic half-space, offering an effective way to approximate the solution of a quarter-space.

本研究对弹性四分之一空间接触中的边缘效应进行了数值研究。在边界元方法中实现了 Hetényi 方法的扩展，即重叠两个弹性半空间，从而获得了顶面和侧面均可受力的弹性四分之一空间的解。在研究刚性球体在弹性四分之一空间上的压痕试验时，通过拟合数值结果得到了法向力、平均接触半径、接触面积上的压力分布以及内部 von Mises 应力与球体从侧边开始的位置的相关性。这些方程还可用于解释与压痕深度相关的接触行为：从压痕开始时的赫兹接触到大压痕深度时的非圆形接触。此外，还将结果与四分之一空间的接触情况进行了比较，其中四分之一空间的侧表面并非完全自由：侧表面的剪应力消失，但存在法向应力。后一种情况产生的结果非常相似，尤其是接触面积，但通过在弹性半空间上施加对称载荷，其解法更容易实现，为近似四分之一空间的解法提供了有效途径。

Mechanics of Materials

Phase field modeling of thermal fatigue crack growth in elastoplastic solids and experimental verification

Du Chenyu, Cui Haitao, Zhang Hongjian, Cai Zhibin, Zhai Weikuo

doi:10.1016/j.mechmat.2023.104839

弹塑性固体热疲劳裂纹生长的相场建模与实验验证

It is challenging to simulate thermal fatigue crack growth in elastoplastic solids, meanwhile, the phase field model is very attractive for simulating complex cracking problems. A thermal-elastoplastic phase field model for thermal fatigue was developed, and its accuracy and availability were verified by typical examples. Then a verified thermal fatigue experiment of the V-notch specimen was carried out and the crack growth was simulated based on the phase field model. The results indicate that the process of thermal fatigue crack in elastoplastic solids from initiation to propagation is effectively simulated by the proposed phase field model. As the regularization length increases, the simulated crack has a longer length and stronger diffusivity. The appropriate regularization length needs to be determined based on experimental results.

在弹塑性固体中模拟热疲劳裂纹生长具有挑战性，而相场模型对于模拟复杂的裂纹问题非常有吸引力。本文建立了热疲劳弹塑性相场模型，并通过典型实例验证了该模型的准确性和可用性。然后对 V 型缺口试样进行了验证性热疲劳实验，并根据相场模型模拟了裂纹的生长过程。结果表明，所提出的相场模型能有效模拟弹塑性固体中热疲劳裂纹从产生到扩展的过程。随着正则化长度的增加，模拟裂纹的长度更长，扩散性更强。需要根据实验结果确定合适的正则化长度。

Thin-Walled Structures

Exploring guided wave propagation in composite cylindrical shells with an embedded delamination through refined spectral element method

Hua Fenfei, You Qingquan, Huang Qingyang, Fu Wanbiao, Zhou Xiaoqiang

doi:10.1016/j.tws.2023.111326

通过精炼谱元法探索嵌入分层的复合圆柱壳中的导波传播

The elastic wave propagation in a thin-walled composite structure carries information concerning its material properties and structural discontinuities. Towards the damage identification, a refined spectral element method (SEM) is presented to explore the guided wave propagation in composite cylindrical shells with embedded delamination. The governing equations and the natural boundary conditions are derived using the first-order shear deformation theory along with the Hamilton's principle. The spectral shell element is established via the exact strong-form solutions, and the dynamic stiffness matrix is formulated through the force-displacement relations. Transforming the wave differential equations into the frequency domain, the numerical Laplace transform is applied to solve the inverse problems. Following a sub-laminate approach, the delamination is modeled by means of four spectral elements and the interface continuity conditions. In addition, the stiffness reduction method is introduced to approximate the delamination. A comparison with published results in terms of the natural frequencies is made to verify the accuracy of the SEM. The dispersion characteristics of the cylindrical shell are examined including the wave number, phase and group velocities. The interaction of guided waves with the delamination is revealed. The influences of the length, depth, and position of the delamination on the wave responses are demonstrated.

薄壁复合材料结构中的弹性波传播蕴含着有关其材料特性和结构不连续性的信息。为了进行损伤识别，本文提出了一种改进的谱元法 (SEM)，用于探索具有嵌入分层的复合材料圆柱壳中的导波传播。利用一阶剪切变形理论和汉密尔顿原理推导出治理方程和自然边界条件。通过精确的强形式解建立了频谱壳元素，并通过力-位移关系制定了动态刚度矩阵。将波微分方程转换到频域，应用数值拉普拉斯变换解决逆问题。采用子层压方法，通过四个频谱元素和界面连续性条件对分层进行建模。此外，还引入了刚度减小法来近似分层。与已公布的自然频率结果进行了比较，以验证 SEM 的准确性。研究了圆柱形壳体的频散特性，包括波数、相位和群速度。揭示了导波与分层的相互作用。演示了分层的长度、深度和位置对波响应的影响。

来源：复合材料力学仿真Composites FEM

【新文速递】2023年10月21日复合材料SCI期刊最新文章

今日更新：Composite Structures 1 篇，Composites Part A: Applied Science and Manufacturing 1 篇，Composites Part B: Engineering 1 篇，Composites Science and Technology 1 篇Composite StructuresStochastic interpretable machine learning based multiscale modeling in thermal conductivity of Polymeric Graphene-enhanced compositesLiu Bokai, Lu Weizhuo, Olofsson Thomas, Zhuang Xiaoying, Rabczuk Timondoi:10.1016/j.compstruct.2023.117601基于随机可解释机器学习的聚合物石墨烯增强复合材料导热性多尺度建模We introduce an interpretable stochastic integrated machine learning based multiscale approach for the prediction of the macroscopic thermal conductivity in Polymeric graphene-enhanced composites (PGECs). This method encompasses the propagation of uncertain input parameters from the meso to macro scale, implemented through a foundational bottom-up multi-scale framework. In this context, Representative Volume Elements in Finite Element Modeling (RVE-FEM) are employed to derive the homogenized thermal conductivity. Besides, we employ two sets of techniques: Regression-tree-based methods (Random Forest and Gradient Boosting Machine) and Neural networks-based approaches (Artificial Neural Networks and Deep Neural Networks). To ascertain the relative influence of factors on output estimations, the SHapley Additive exPlanations (SHAP) algorithm is integrated. This interpretable machine learning methodology demonstrates strong alignment with published experimental data. It holds promise as an efficient and versatile tool for designing new composite materials tailored to applications involving thermal management.我们介绍了一种基于随机综合机器学习的多尺度可解释方法，用于预测聚合物石墨烯增强复合材料（PGEC）的宏观热导率。该方法通过自下而上的多尺度基础框架，将不确定的输入参数从中观尺度传播到宏观尺度。在此背景下，我们采用了有限元建模中的代表性体积元素（RVE-FEM）来推导均质化热导率。此外，我们还采用了两套技术：基于回归树的方法（随机森林和梯度提升机）和基于神经网络的方法（人工神经网络和深度神经网络）。为了确定各因素对输出估计的相对影响，还集成了 SHapley Additive exPlanations（SHAP）算法。这种可解释的机器学习方法与已公布的实验数据非常吻合。它有望成为设计新型复合材料的高效多功能工具，为涉及热管理的应用量身定制。Composites Part A: Applied Science and ManufacturingElectromagnetic interference shielding composites and the foams with gradient structure obtained by selective distribution of MWCNTs into hard domains of thermoplastic polyurethaneWang Xiaohan, Zou Fangfang, Zhao Yishen, Li Guangxian, Liao Xiadoi:10.1016/j.compositesa.2023.107861电磁干扰屏蔽复合材料，以及通过在热塑性聚氨酯硬域中选择性分布 MWCNT 而获得的梯度结构泡沫In this paper, multilayer thermoplastic polyurethane (TPU)/multiwalled carbon nanotubes (MWCNTs) electromagnetic interference shielding composite foams with gradient structure was prepared. The gradient distribution of effective concentration of filler and cell size were realized by selective distribution of MWCNTs into hard domains of TPU, which improved interlayer interface polarization of electromagnetic waves and impedance matching between the material and the air. The average electromagnetic interference shielding efficiency (EMI SE) of TPU/MWCNTs composites with gradient structure is 1.2 times larger than that of homogeneous composites. After foaming, the average EMI SE of the gradient foams was higher than that of the homogeneous foams, with maximum average EMI SE of 35.4 dB. This work is the first time to correlate the interaction of fillers with the soft domains and hard domains of TPU and EMI shielding performance, providing a feasible method for designing lightweight composites with low filler and better EMI shielding performance.本文制备了具有梯度结构的多层热塑性聚氨酯（TPU）/多壁碳纳米管（MWCNTs）电磁干扰屏蔽复合泡沫。通过将 MWCNTs 选择性地分布在 TPU 的硬域中，实现了填料有效浓度和单元尺寸的梯度分布，从而改善了电磁波的层间界面极化以及材料与空气之间的阻抗匹配。梯度结构 TPU/MWCNTs 复合材料的平均电磁干扰屏蔽效率（EMI SE）是均质复合材料的 1.2 倍。发泡后，梯度泡沫的平均 EMI SE 高于均质泡沫，最大平均 EMI SE 为 35.4 dB。这项研究首次将填料与热塑性聚氨酯软域和硬域的相互作用与 EMI 屏蔽性能联系起来，为设计低填料、EMI 屏蔽性能更好的轻质复合材料提供了可行的方法。Composites Part B: EngineeringMultifunctional basalt fiber polymer composites enabled by carbon nanotubes and grapheneBalaji K.V., Shirvanimoghaddam Kamyar, Naebe Minoodoi:10.1016/j.compositesb.2023.111070利用碳纳米管和石墨烯实现玄武岩纤维聚合物复合材料的多功能性Basalt fiber (BF) is an eco-friendly fiber that can mitigate environmental footprint by enabling lightweight composite systems and components. When combined with carbonaceous structures such as carbon nanotubes (CNT) and graphene, these fibers can form multi-scale composites with remarkable potential for creating smart composites with added functionalities. In this paper, we review various fiber treatment methods used for nanomaterials, which include chemical vapor deposition (CVD), electrophoretic deposition, sizing, dipping, and chemical grafting. Compared to matrix modification, fiber treatment methods are more efficient in facilitating better load transfer between the matrix resin and fiber reinforcement through a nanomaterial bridge. Custom sizing with nanomaterials and CVD processes without a catalyst have been found the most effective methods for immobilizing nanomaterials onto the fibers. This advancement sets the stage for a new generation of sustainable and functional polymer composites that can support a circular economy.玄武岩纤维（BF）是一种生态友好型纤维，可实现复合材料系统和组件的轻量化，从而减少对环境的影响。当与碳纳米管（CNT）和石墨烯等碳质结构相结合时，这些纤维可以形成多尺度复合材料，在创造具有附加功能的智能复合材料方面具有显著的潜力。本文综述了用于纳米材料的各种纤维处理方法，包括化学气相沉积（CVD）、电泳沉积、上浆、浸渍和化学接枝。与基体改性相比，纤维处理方法能更有效地通过纳米材料桥在基体树脂和纤维增强材料之间更好地传递载荷。使用纳米材料定制尺寸和不使用催化剂的 CVD 工艺是将纳米材料固定在纤维上的最有效方法。这一进步为新一代可支持循环经济的可持续功能性聚合物复合材料奠定了基础。Composites Science and TechnologySuper-tough, super-elastic, temperature-responsive, and tunable viscoelastic elastomer enabled by embedding nanosized liquid metal dropletsLi Sai, Zhao Hengheng, Liu Minghui, Zeng Xiaofei, Wei Yuan, Zhang Ganggang, Liu Jun, Zhang Liqundoi:10.1016/j.compscitech.2023.110311 通过嵌入纳米级液态金属液滴实现超强韧性、超强弹性、温度响应性和可调粘弹性弹性体Liquid metal (LM) based composites are playing irreplaceable roles in many emerging fields such as stretchable and wearable electronics, soft robotics. However, it is still challenging to facilely fabricate the LM-based elastomers with nanosized and well-dispersed LM domains. Herein, the LM droplets filled elastomer nanocomposites (ENCs) with temperature-responsive, super-tough, super-elastic and tunable viscoelastic properties are introduced. By employing the conventional rubber processing method, LM is fragmented into nanoscale droplets and dispersed uniformly in cross-linked natural rubber (NR) without compromising the soft and highly stretchable properties of the matrix. In addition to the remarkable enhancement in tear resistance, the toughness of the resulting composites is strikingly improved as lowering the applied temperature, which is attributed to the phase transition and the simultaneous volume expansion of LM droplets. Surprisingly, for the viscoelasticity, this LM-based ENCs exhibit almost the same dynamic hysteresis with the pure NR system at the service condition of automobile tires, which is remarkably reduced compared to the traditional ENCs filled with rigid nanoparticles. Furthermore, this material also shows a good damping property for noise attenuation in the case of submarine covering. Collectively, this work opens a new avenue for the next generation of high-performance and multifunctional ENCs equipped in low-temperature working conditions.基于液态金属（LM）的复合材料在许多新兴领域发挥着不可替代的作用，例如可拉伸和可穿戴电子设备、软机器人技术等。然而，如何方便地制造具有纳米尺寸和良好分散的液态金属畴的液态金属基弹性体仍是一项挑战。本文介绍了具有温度响应、超韧性、超弹性和可调粘弹性能的 LM 液滴填充弹性体纳米复合材料（ENCs）。通过采用传统的橡胶加工方法，LM 被破碎成纳米级液滴，并均匀地分散在交联天然橡胶（NR）中，而不会影响基体的柔软和高拉伸性能。除了抗撕裂性显著增强外，随着应用温度的降低，所得复合材料的韧性也显著提高，这归因于 LM 液滴的相变和同时的体积膨胀。令人惊讶的是，在粘弹性方面，这种基于 LM 的 ENC 在汽车轮胎的使用条件下表现出与纯 NR 系统几乎相同的动态滞后，与填充了刚性纳米颗粒的传统 ENC 相比明显减少。此外，这种材料还显示出良好的阻尼特性，可用于海底覆盖层的噪声衰减。总之，这项工作为在低温工作条件下装备下一代高性能、多功能 ENC 开辟了一条新途径。来源：复合材料力学仿真Composites FEM