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【新文速递】2024年3月24日固体力学SCI期刊最新文章

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今日更新:Journal of the Mechanics and Physics of Solids 1 篇,Mechanics of Materials 1 篇,Thin-Walled Structures 4 篇

Journal of the Mechanics and Physics of Solids

Propagation of solitary waves in origami-inspired metamaterials

Quan Zhang, Stephan Rudykh

doi:10.1016/j.jmps.2024.105626

孤波在折纸启发超材料中的传播

We propose a design strategy for creating origami-like mechanical metamaterials with diverse non-linear mechanical properties and capable of remote actuation. The proposed triangulated cylindrical origami (TCO)-inspired metamaterials enable the highly desirable strain-softening/hardening and snap-through behaviors via a multi-material and highly deformable hinge design. Moreover, we couple these novel non-linear mechanical properties of the TCO origami-inspired metamaterials with the transformative ability of hard-magnetic active materials, allowing for untethered shape- and property-actuation in the developed metamaterials. We develop a mathematical modeling framework for the proposed TCO origami-inspired metamaterials, building on approximating the highly deformable hinges as a combination of longitudinal and rotational springs. We validate the accuracy of the developed mathematical modeling approach by comparing the analytically predicted compressive response of a unit cell structure with the corresponding numerical and experimental results. Using the developed mathematical modeling framework, we investigate the magnetic field-induced large deformation and superimposed solitary wave propagation in the TCO origami-inspired metamaterial system. We show that the proposed metamaterial allows us to tune the key characteristics of the enabled non-linear solitary waves, including their characteristic width and amplitude. The proposed design strategy for readily manufacturable origami-inspired metamaterial systems paves a novel path for practical engineering applications. Our studies also underscore the potential of magneto-mechanical interaction in the design of reconfigurable metamaterial systems with superior non-linear mechanical and elastic wave properties.

我们提出了一种设计策略,用于制造具有多种非线性机械特性并能够远程驱动的类似折纸的机械超材料。受三角圆柱折纸(TCO)启发而提出的超材料通过多材料和高变形铰链设计,实现了非常理想的应变软化/硬化和卡穿行为。此外,我们还将 TCO 折纸启发超材料的这些新型非线性机械特性与硬磁性活性材料的转换能力结合起来,使所开发的超材料能够实现无束缚的形状和特性致动。我们在将高变形铰链近似为纵向弹簧和旋转弹簧组合的基础上,为拟议的 TCO 起源启发超材料开发了一个数学建模框架。我们通过比较单元结构的分析预测压缩响应与相应的数值和实验结果,验证了所开发的数学建模方法的准确性。利用所开发的数学建模框架,我们研究了磁场诱导的大变形和叠加孤波在 TCO 起源启发超材料系统中的传播。我们的研究表明,所提出的超材料允许我们调整所启用的非线性孤波的关键特性,包括其特征宽度和振幅。针对可随时制造的折纸启发超材料系统提出的设计策略为实际工程应用铺平了一条新路。我们的研究还强调了磁-机械相互作用在设计具有卓越非线性机械波和弹性波特性的可重构超材料系统方面的潜力。


Mechanics of Materials

The interfacial behavior of an axisymmetric film bonded to a graded inhomogeneous substrate

Dengke Li, Peijian Chen, Hao Liu, Zhilong Peng, Mehmet Ali Guler, Shaohua Chen

doi:10.1016/j.mechmat.2024.104983

轴对称薄膜与渐变不均匀基底的界面行为

With the development of high-tech applications such as thermal barrier coatings, stretchable and flexible electronics, etc, the key film/substrate systems are more commonly involving three-dimensional axisymmetric problems with graded inhomogeneous substrates. In these film/substrate systems, the effects of geometric and material factors of both the films and the substrates on the interfacial behavior are urgently needed to be uncovered. Herein, a novel theoretical axisymmetric model of an elastic film bonded to a graded substrate is proposed and solved by using Hankel integral transformation and orthotropic polynomials. The interfacial shear stress and the corresponding shear stress intensity factor as well as radial stresses and hoop stresses of both the film and the graded substrate are obtained. It is found that the present model works well to predict the interfacial behavior between an axisymmetric film and a graded substrate. Compared with cases with homogeneous substrates, choosing graded substrates can reduce the risk of edge fracture on the surface of the substrate. A film with a smaller elastic modulus and thickness is advantageous for the interface reliability of the film/substrate system under a thermal load. The results should be useful for not only understanding the load transfer mechanism of axisymmetric film/substrate system, but also providing a valuable guidance to optimize film/substrate structures in various practical and potential applications.

随着热障涂层、可拉伸和柔性电子器件等高科技应用的发展,关键的薄膜/基底系统越来越多地涉及具有梯度不均匀基底的三维轴对称问题。在这些薄膜/基底体系中,迫切需要揭示薄膜和基底的几何和材料因素对界面行为的影响。本文提出了一种新的弹性薄膜与分级基底粘合的轴对称理论模型,并利用汉克尔积分变换和正交多项式进行了求解。得到了界面剪应力和相应的剪应力强度因子,以及薄膜和分级基底的径向应力和箍应力。研究发现,本模型能很好地预测轴对称薄膜和分级基底之间的界面行为。与均匀基底的情况相比,选择分级基底可以降低基底表面边缘断裂的风险。弹性模量和厚度较小的薄膜有利于薄膜/基底系统在热负荷下的界面可靠性。研究结果不仅有助于理解轴对称薄膜/基底系统的载荷传递机理,还为优化薄膜/基底结构在各种实际和潜在应用中提供了宝贵的指导。


Thin-Walled Structures

Development and validation analysis of a steel-lead hybrid dual-yield BRB for multi-stage seismic energy dissipation

Mingming Jia, Yinzhen Chen, Peisi Jin

doi:10.1016/j.tws.2024.111822

用于多级地震消能的钢铅混合双屈服 BRB 的开发和验证分析

To address the limitations inherent in conventional all-steel buckling restrained braces (BRBs) that maintain elastic behavior and lack seismic energy dissipation during frequent earthquakes (FEs), this study proposes a novel approach of combining lead dampers with BRB, forming the development of steel-lead hybrid dual-yield BRB (or simply dual-yield BRB). Integrating lead material into the dual-yield BRB harnesses its dynamic recrystallization capacity, allowing the lead dampers to yield and efficiently dissipate seismic energy during FEs via well-designed configurations. This study delineates the approach for connecting lead dampers to BRBs and performs comparative quasi-static tests on dual-yield BRBs and conventional BRBs. Key observations from the laboratory tests confirmed that lead dampers experience earlier failure compared to inner cores. Dual-yield BRB exhibited significantly lower initial displacement requirements for energy dissipation than conventional BRB, demonstrating a hexagonal hysteretic curve, trilinear behavior in the skeleton curve, and superior overall energy dissipation capacity at small displacements. The feasible strategy of refined numerical simulations was initially validated based on experimental results. Subsequently, to enhance analysis efficiency, simplified models using truss elements were developed and endorsed. Elasto-plastic time history analyses were performed on benchmark models of 9-story steel frames, considering scenarios with no bracing, conventional BRBs, and dual-yield BRBs, exposed to FEs and maximum considered earthquakes (MCEs). Various parameters, including component forces, structural displacement and damping underwent thorough examination. These findings underscore the exceptional seismic performance and energy dissipation abilities of dual-yield BRBs, solidifying them as a valuable addition to earthquake-resistant structural systems.

传统的全钢屈曲约束支撑(BRBs)在频繁地震(FEs)中只能保持弹性行为而缺乏地震能量耗散,为了解决这种固有的局限性,本研究提出了一种将铅阻尼器与 BRB 结合的新方法,形成了钢铅混合双屈服 BRB(或简称双屈服 BRB)。将铅材料集成到双屈服 BRB 中可利用其动态再结晶能力,使铅阻尼器在 FE 期间通过精心设计的配置屈服并有效消散地震能量。本研究阐述了将铅阻尼器连接到 BRB 的方法,并对双韧性 BRB 和传统 BRB 进行了准静力对比试验。实验室测试的主要观察结果证实,与内芯相比,铅阻尼器会更早失效。与传统 BRB 相比,双矢量 BRB 在消能方面的初始位移要求明显降低,表现出六边形滞回曲线、骨架曲线的三线性行为,以及在小位移时卓越的整体消能能力。在实验结果的基础上,初步验证了精细数值模拟的可行策略。随后,为提高分析效率,开发并认可了使用桁架元素的简化模型。对 9 层钢架的基准模型进行了弹塑性时间历程分析,考虑了无支撑、传统 BRB 和双屈服 BRB 的情况,并暴露于 FE 和最大考虑地震 (MCE) 中。对各种参数,包括构件力、结构位移和阻尼进行了全面检查。这些发现强调了双屈服 BRB 的卓越抗震性能和消能能力,使其成为抗震结构系统的重要补充。


A model for the temperature-dependent creep/recovery behavior of dry fiber fabric considering in-plane tension

Yanpeng Si, Zhiyong Zhao, Lishuai Sun, Junzhen Chen, Yujun Li, Jianjun Jiang

doi:10.1016/j.tws.2024.111817

考虑平面张力的干纤维织物随温度变化的蠕变/恢复行为模型

In the manufacturing process of fiber-reinforced composite materials, the preforming of dry fiber fabrics is typically carried out under specific out-of-plane pressure, in-plane tension, and at designated temperatures. The fabric exhibits significant time and temperature-dependent permanent deformation as well as creep/recovery behavior. Gaining a better understanding of these phenomena and harnessing predictive capabilities will be instrumental in achieving more precise control over fiber volume fraction and material composition. In this paper, creep/recovery experiments and cyclic loading-unloading tests were conducted on CF3031 dry fiber preforms under various in-plane tensions and temperatures, measuring in-plane strains using Fiber Bragg Grating (FBG) sensors. Based on this data, a modified Burgers viscoelastic-plastic model has been proposed to describe the time-dependent creep/recovery behavior of dry fiber fabric preforming under the coupled effects of in-plane tension, out-of-plane pressure, and temperature variations. This model employs a single set of equations and parameters to represent the complete creep/recovery process of the material. The experimental results align well with the predicted outcomes across different compression scenarios.

在纤维增强复合材料的制造过程中,干纤维织物的预成型通常是在特定的平面外压力、平面内张力和指定温度下进行的。织物会表现出明显的随时间和温度变化的永久变形以及蠕变/恢复行为。更好地了解这些现象并利用预测能力将有助于实现对纤维体积分数和材料成分的更精确控制。本文在各种面内张力和温度条件下对 CF3031 干纤维预型件进行了蠕变/恢复实验和循环加载-卸载测试,并使用光纤布拉格光栅 (FBG) 传感器测量面内应变。根据这些数据,我们提出了一个改进的布尔格斯粘弹塑性模型,用于描述干纤维织物预制件在平面内张力、平面外压力和温度变化的耦合作用下随时间变化的蠕变/恢复行为。该模型采用单组方程和参数来表示材料的整个蠕变/恢复过程。实验结果与不同压缩情况下的预测结果非常吻合。


Approximate closed-form solutions for free vibration of circular arches with discrete lateral braces

Chen Long-Kai, Chen Hai-Jun, Cai Yong

doi:10.1016/j.tws.2024.111820

带离散侧向支撑的圆拱自由振动的近似闭式解法

Discrete lateral braces are commonly employed to enhance the out-of-plane stability of arches. However, these braces generate coupling effects among vibration modes, which significantly impact the vibration characteristics of the arches. This paper presents an analytical solution for the free vibration analysis of two-hinged arches with equally-spaced lateral translational and/or rotational braces. A simplified method of evaluating the fundamental frequency for the out-of-plane vibration of arches with equally-spaced lateral braces is introduced. The method relies on the conventional approach of representing arch braces through elastic springs, but here the out-of-plane deflection of the braced arch is constructed by adding related coupled sinusoidal functions to that of the unbraced arch, satisfying both the boundary and kinematic conditions. Subsequently, the fundamental frequency and threshold bracing stiffness or stiffness requirement are derived using the Rayleigh–Ritz method. Finite element analysis (FEA) is applied to investigate the flexural-torsional vibration mode and fundamental frequency of arches with discrete braces, and the results from FEA closely match the theoretical predictions. The effects of number of lateral translational and/or rotational brace, out-of-plane slenderness, included angle, bracing stiffness and bracing position on the fundamental frequency are comprehensively analyzed. It is found that when the fundamental frequency of the braced arch increases due to changes in bracing stiffness, the mode shape displays more intricate behavior, rather than following a straightforward low-to-high mode growth pattern. Furthermore, it is observed that in some cases, the addition of rotational bracing stiffness can markedly enhance the maximum fundamental frequency of the arch with both translational and rotational braces.

离散侧向支撑通常用于增强拱形结构的平面外稳定性。然而,这些支撑会产生振动模式之间的耦合效应,从而严重影响拱形结构的振动特性。本文提出了一种分析方法,用于分析带有等间距横向平移和/或旋转支撑的双铰接拱的自由振动。本文介绍了一种简化方法,用于评估带有等间距横向支撑的拱门平面外振动的基频。该方法依赖于通过弹性弹簧表示拱形支撑的传统方法,但在这里,支撑拱形的平面外挠度是通过在无支撑拱形的平面外挠度上添加相关耦合正弦函数来构建的,同时满足边界条件和运动条件。随后,利用雷利-里兹法得出基频和阈值支撑刚度或刚度要求。应用有限元分析(FEA)研究了带有离散支撑的拱的挠扭振动模式和基频,有限元分析的结果与理论预测非常吻合。全面分析了横向平移和/或旋转支撑数量、平面外细长度、包含角、支撑刚度和支撑位置对基频的影响。研究发现,当支撑拱的基频因支撑刚度的变化而增加时,模态形状会表现出更复杂的行为,而不是简单的从低到高的模态增长模式。此外,研究还发现,在某些情况下,增加旋转支撑刚度可显著提高具有平移和旋转支撑的拱的最大基频。


Experimental and numerical investigation on residual stress and deformation of welded I-section curved steel beams

Fei Xu, Yun Zhao, Ju Chen, Xu Liu, Yuner Huang

doi:10.1016/j.tws.2024.111821

焊接 I 型截面弯曲钢梁残余应力和变形的实验与数值研究

This paper presents an experimental and numerical investigation on welding-induced residual stresses and deformations of in-plane curved welded I-section steel beams. Two welded curved beams with different curvatures were investigated. After welding the curved beam, the residual deformations were measured by a 3D scanner. The residual stresses were subsequently obtained through a high-precision sectioning method. The effects of curvature on the magnitude and distributions of residual deformations and stresses at the specific sections were analysed with the test results. It was found that the residual deformation gradually increased from the weld region to both ends of the flange plate, and the torsion in the web plate became severe with a decrease in curvature of the curved beam. Moreover, the welding process of the curved beam was simulated using the finite element (FE) method. The developed FE model was validated against the test results, and thereafter, parametric analyses were conducted to assess the influence of welding sequence, welding speed, and curvatures of the curved beam on the welding residual stresses and deformations. The numerical results demonstrated that the residual stresses and deformations were significantly influenced by welding speeds, but the influence from curvature of the curved beam was relatively small. Finally, a reasonable welding sequence, welding speed, and curvature of the curved beams were recommended.

本文介绍了对平面内曲线焊接工字形钢梁的焊接引起的残余应力和变形进行的实验和数值研究。研究了两根不同曲率的焊接弯梁。曲面梁焊接后,残余变形由三维扫描仪测量。残余应力随后通过高精度截面方法获得。测试结果分析了曲率对特定截面上残余变形和应力的大小及分布的影响。结果发现,残余变形从焊接区域到翼缘板的两端逐渐增大,腹板的扭转随着弯曲梁曲率的减小而变得严重。此外,还使用有限元(FE)方法模拟了弯梁的焊接过程。开发的 FE 模型与试验结果进行了验证,随后进行了参数分析,以评估焊接顺序、焊接速度和弯曲梁的曲率对焊接残余应力和变形的影响。数值结果表明,焊接速度对焊接残余应力和变形的影响很大,但曲梁曲率的影响相对较小。最后,推荐了合理的焊接顺序、焊接速度和弯梁曲率。



来源:复合材料力学仿真Composites FEM
ACTMechanicalSystemInspireMAGNET振动断裂复合材料非线性电子焊接理论材料控制试验
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【新文速递】2024年3月26日复合材料SCI期刊最新文章

今日更新:Composite Structures 11 篇Composite StructuresDynamic response of magneto-electro-elastic composite plates lying on visco-Pasternak medium subjected to blast loadQuoc-Hoa Pham, Van Ke Tran, Phu-Cuong Nguyendoi:10.1016/j.compstruct.2024.118054位于粘滞-帕斯捷尔纳克介质上的磁弹性复合板在爆炸荷载作用下的动态响应This is the first endeavor to present a finite element approach to predict free oscillation and transient characteristics of magneto-electro-elastic (MEE) composite rectangular and elliptical plates resting on the visco-Pasternak medium in a hygro-thermal environment subjected to blast load. The variation of electric and magnetic potentials along the thickness direction of the MEE plate is determined via the Maxwell equation and magneto-electric boundary condition. The governing equations of motion for the MEE plate are obtained using refined higher-order shear plate theory and Hamilton's principle. Stiffness matrices, mass matrices, damping matrices, and force vectors of the plate are derived using a four-node quadrilateral element with eight degrees of freedom per node approximated using C1-order non-conforming Hermite and Lagrange functions. In addition, the Navier close-form solutions for rectangular plates with simply supported boundary conditions are used as a useful comparison tool for the numerical solutions. Dynamic response results of plates were obtained using Newmark's direct integration written by Matlab's programming. The accuracy of the method is verified through numerical comparison with confidence statements. The results show that the applied magnetic and electric potential highly inspires the transient responses. These results can be used in vibration control studies of structures and structures subjected to explosive or low-velocity impact loads.这是首次提出一种有限元方法,用于预测磁电弹性(MEE)复合矩形板和椭圆板的自由振荡和瞬态特性,这些复合矩形板和椭圆板位于承受爆炸荷载的湿热环境中的粘滞-帕斯捷尔纳克介质上。电势和磁势沿 MEE 板厚度方向的变化是通过麦克斯韦方程和磁电边界条件确定的。利用精炼的高阶剪切板理论和汉密尔顿原理获得了 MEE 板的支配运动方程。板的刚度矩阵、质量矩阵、阻尼矩阵和力矢量是使用四节点四边形元素推导出来的,每个节点有八个自由度,使用 C1 阶非符合赫米特函数和拉格朗日函数进行近似。此外,还使用了具有简单支撑边界条件的矩形板的纳维耶近似形式解作为数值解的有用比较工具。利用 Matlab 编程编写的纽马克直接积分法获得了板的动态响应结果。通过与置信度声明进行数值比较,验证了该方法的准确性。结果表明,外加磁势和电动势对瞬态响应有很大影响。这些结果可用于受爆炸或低速冲击载荷作用的结构和构造物的振动控制研究。An aero-structure-acoustics evaluation framework of wind turbine blade cross-section based on Gradient Boosting regression treeGuangxing Guo, Weijun Zhu, Zhenye Sun, Shifeng Fu, Wenzhong Shen, Jiufa Caodoi:10.1016/j.compstruct.2024.118055基于梯度提升回归树的风力涡轮机叶片横截面气动-结构-声学评估框架Under the rapid development of wind turbines, the rotor size has substantially increased in recent years. To meet the key design criteria, finding a trade-off between aerodynamic, structure and noise (ASN) impact becomes a challenging problem. The blade cross-section is the basic element of the blade, its outer contour is the airfoil profile that produces aerodynamic loads as well as noise, and the inner part is the supporting composite material that provides enough stiffness to balance the loads. Modifying local blade sections can adjust the rotors’ overall performance. However, in the work of blade-combined ASN optimization, the iterative process using traditional numerical simulation methods becomes extremely heavy. In this study, a sustainable database is created based on a large number of calculations of aerodynamic, structural and noise attributes at various cross-sections. Then a platform named AFML (Airfoil machine learning) for simultaneously predicting the comprehensive performance of the cross-section is constructed by using the integrated Gradient Boosting Regression Tree algorithm. Results show that the prediction accuracy of AFML is acceptable even for unseen inflow conditions. By calling the pre-trained AFML, ASN data of the cross-section can be immediately obtained, and the blade shape and inner structure can be updated quickly.近年来,随着风力涡轮机的快速发展,其转子尺寸也大幅增加。为了满足关键的设计标准,如何在空气动力、结构和噪声(ASN)影响之间找到平衡点成为一个具有挑战性的问题。叶片横截面是叶片的基本要素,其外部轮廓是产生气动载荷和噪声的机翼轮廓,内部则是提供足够刚度以平衡载荷的支撑复合材料。对叶片局部进行修改可以调整转子的整体性能。然而,在叶片组合 ASN 优化工作中,使用传统数值模拟方法的迭代过程变得异常繁重。在本研究中,基于对不同截面的气动、结构和噪声属性的大量计算,创建了一个可持续数据库。然后,利用集成梯度提升回归树算法构建了一个名为 AFML(机翼机器学习)的平台,用于同时预测横截面的综合性能。结果表明,AFML 的预测精度是可以接受的,即使是在不可见的流入条件下。通过调用预训练的 AFML,可以立即获得横截面的 ASN 数据,并快速更新叶片形状和内部结构。Behavior and design of functionally graded concrete subject to triple impacts of the shaped charge, projectile penetration and explosionXuexiang Yin, Jianzhong Lai, Longyu Du, Jiehang Zhou, Ningyu Kangdoi:10.1016/j.compstruct.2024.118061受定型装药、射弹穿透和爆炸三重影响的功能级配混凝土的行为和设计The present issue is how to improve the concrete structure to resist multiple impacts of the tandem warhead. This study developed an approach to design a functionally graded concrete (FGC) structure with fiber-graded (FG) and centralized high-strength aggregates (CHSA) to address this issue. The enhancement of the FG and CHSA in the concrete structure was verified by static mechanical performance tests and dynamic compressive simulation. The behavior of the FGC structure subject to the tandem warhead was investigated by the experimental and numerical dynamic destructive tests, including three stages: shaped charge, projectile penetration and explosion. There are three types of targets, including ultra-high-performance concrete (UHPC), ceramic aggregate reinforced (CAR) FGC and steel aggregate reinforced (SAR) FGC. The results showed that the SAR-FGC had the best multiple-impact resistance in concrete structures. The blocking effect to impact waves was improved by increasing the wave impedance of the anti-penetration layer. Energy absorption was increased by 7 times through the combined action of functional structures to ameliorate damage distribution. The triple destruction depth of it was reduced by 36% compared to UHPC. According to the Forrestal empirical equation, a penetration depth model was proposed for the FGC with jet damage.目前的问题是如何改进混凝土结构,以抵御串联弹头的多次撞击。为解决这一问题,本研究开发了一种方法来设计一种含有纤维级配(FG)和集中高强度骨料(CHSA)的功能级配混凝土(FGC)结构。通过静态力学性能测试和动态抗压模拟,验证了 FG 和 CHSA 在混凝土结构中的增强作用。通过实验和数值动态破坏试验研究了 FGC 结构在串联弹头作用下的行为,包括三个阶段:定型装药、弹丸穿透和爆炸。目标有三种类型,包括超高性能混凝土(UHPC)、陶瓷骨料加固(CAR)FGC 和钢骨料加固(SAR)FGC。结果表明,SAR-FGC 在混凝土结构中具有最佳的抗多重冲击能力。通过增加抗穿透层的波阻抗,提高了对冲击波的阻挡效果。通过功能结构的联合作用,能量吸收提高了 7 倍,从而改善了破坏分布。与超高强度混凝土相比,其三重破坏深度减少了 36%。根据福雷斯塔尔经验方程,提出了具有喷射破坏的 FGC 的穿透深度模型。Connectivity patterns in lead-free piezocomposites: A critical analysis for 0-3 and 1-3 configurationsFrancisco J. Cañamero, Federico C. Buroni, Luis Rodríguez-Temblequedoi:10.1016/j.compstruct.2024.118062无铅压电复合材料中的连接模式:0-3 和 1-3 配置的关键分析In the quest for eco-friendly alternatives within materials science, the development of sustainable and non-toxic piezoelectric composites is of utmost importance. This study undertakes a computational exploration to elucidate the influence of phase connectivity on the engineering performance of lead-free piezocomposites. Employing a combination of analytical and numerical methodologies, we critically evaluated various figures of merit across different microstructural configurations, juxtaposing these findings with traditional lead zirconate titanate (PZT)-based materials. Our analysis considers 0-3 and 1-3 connectivity patterns, incorporating active phases in the form of spherical particles and cylindrical fibers. We also examine the impact of carbon nanotubes (CNTs) in enhancing the polymeric matrix, which introduces the potential for network percolation and further mechanical and electrical property optimization. The study yields pivotal insights into the phase connectivity of lead-free piezocomposites, with direct implications for their application in sensing, actuating, and energy harvesting domains. We ascertain that the electromechanical performance of these composites is contingent upon the connectivity pattern and the proportion of active phase. Notably, the KNNS-BNZH & Polyethylene composite demonstrates exceptional potential in 1-3 configurations, while the BTO & PVDF composite distinguishes itself with superior dielectric and piezoelectric responses across varying volume fractions. The strategic infusion of CNTs into the PDMS matrix emerges as a significant enhancer of electromechanical attributes, albeit with performance improvements that are specific to the type of coefficient and CNT concentration. This investigation underscores the nuanced interplay between composite design and microstructural attributes, reinforcing the critical role these factors play in the advancement of effective and eco-conscious piezoelectric materials.在材料科学领域寻求生态友好型替代品的过程中,开发可持续且无毒的压电复合材料至关重要。本研究进行了计算探索,以阐明相连通性对无铅压电复合材料工程性能的影响。我们结合分析和数值方法,对不同微结构配置的各种性能指标进行了严格评估,并将这些结果与传统的锆钛酸铅(PZT)基材料进行了对比。我们的分析考虑了 0-3 和 1-3 连接模式,并结合了球形颗粒和圆柱形纤维形式的活性相。我们还研究了碳纳米管(CNT)在增强聚合物基体方面的影响,这为网络渗透和进一步优化机械和电气性能带来了可能性。这项研究对无铅压电复合材料的相连通性提出了重要见解,并对其在传感、致动和能量收集领域的应用产生了直接影响。我们确定,这些复合材料的机电性能取决于连接模式和活性相的比例。值得注意的是,KNNS-BNZH 和聚乙烯复合材料在 1-3 种配置中表现出非凡的潜力,而 BTO 和聚偏二氟乙烯复合材料则在不同体积分数下表现出卓越的介电和压电响应。将 CNT 战略性地注入 PDMS 基体可显著增强机电属性,尽管性能的提高取决于系数类型和 CNT 浓度。这项研究强调了复合材料设计与微结构属性之间微妙的相互作用,强化了这些因素在开发高效、具有生态意识的压电材料中的关键作用。Modeling dynamic crush behavior of carbon fiber reinforced polymer composite structures using MAT213R.T. Haluza, R.K. Goldberg, T.M. Ricks, J.M. Pereira, K.L. Koudela, C.E. Bakisdoi:10.1016/j.compstruct.2024.118063使用 MAT213 模拟碳纤维增强聚合物复合材料结构的动态挤压行为Modeling crushing of carbon fiber reinforced polymer (CFRP) composites is challenging, and current simulation methodologies involve tuning of non-physical parameters. MAT213, a next-generation material model, has advanced functionality to better simulate dynamic impact loading. The objective of the present investigation is to evaluate the potential for using MAT213 to simulate dynamic crushing of CFRPs. Two sets of simulations were performed: one for calibration based on a set of coupon-level experiments and another for prediction of the response of structural elements. Simulations involving dynamic crushing of flat specimens were iteratively run to calibrate model parameters. The calibration demonstrated that MAT213 could produce a simulated force–displacement response within experimental scatter. The simulated failure morphology was also comparable to the experiments. After successful calibration, predictive simulations of dynamic crushing of C-channel shaped specimens were completed using a simulated crash sled test rig and two pairs of impactor mass/velocity conditions. The simulated force–displacement curve in the crash sled simulations for the lower-velocity condition fell within the experimental scatter, but the stable crush force was underpredicted by 27 % in the higher-velocity simulations. Better correlation in the lower-velocity test condition likely results from the calibration condition being a similar velocity to the lower-velocity crash sled condition.碳纤维增强聚合物(CFRP)复合材料的挤压建模具有挑战性,目前的模拟方法涉及非物理参数的调整。新一代材料模型 MAT213 具有先进的功能,可以更好地模拟动态冲击载荷。本研究旨在评估使用 MAT213 模拟 CFRP 动态挤压的潜力。我们进行了两组模拟:一组是基于一组试样级实验的校准,另一组是用于预测结构元素的响应。通过反复运行涉及平面试样动态挤压的模拟来校准模型参数。校准结果表明,MAT213 可以在实验散度范围内产生模拟的力-位移响应。模拟的破坏形态也与实验结果相当。校准成功后,使用模拟碰撞雪橇试验台和两对撞击器质量/速度条件,完成了 C 形通道试样动态挤压的预测模拟。在低速度条件下,撞击橇模拟的力-位移曲线在实验散点范围内,但在高速模拟中,稳定挤压力被低估了 27%。较低速度测试条件下的相关性更好,可能是因为校准条件与较低速度的碰撞雪橇条件速度相似。An evaluation of large diameter through-thickness metallic pins in compositesGeoffrey Neale, Vinodhen Saaran, Monali Dahale, Alex Skordosdoi:10.1016/j.compstruct.2024.118066对复合材料中大直径穿透厚度金属销钉的评估There is increasing demand for functional through-thickness reinforcement (TTR) in composites using elements whose geometry exceeds limitations of existing TTR methods like tufting, stitching, and z-pinning. Recently, static insertion of large diameter TTR pins into heated prepreg stacks has proven a feasible and robust reinforcement process capable of providing accurate TTR element placement with low insertion forces and lower tow damage compared with existing methods for similar element sizes (>1mm diameter) like post-cure drilling. Local mechanical performance and failure mechanics of these pinned laminates are reported here. Laminates with a single statically inserted pins (1.2, 1.5, and 2.0 mm) can mostly retain their in-plane integrity alongside a local improvement in mode I delamination toughness in carbon fibre-benzoxazine laminates. Tensile strength is mostly unaffected by the pins resulting from delamination suppression, whereas there is up to a doubling of Young’s modulus. Compressive strength is significantly diminished (up to 42 %) in pinned laminates. Interlaminar toughness is improved, and peak toughness is pushed ahead of the crack as pin diameter increases. The lack of significant deterioration in in-plane tensile properties in pinned laminates produced using static insertion can expand the range and forms of materials that can be inserted compared to existing TTR.在复合材料中使用几何形状超出现有 TTR 方法(如簇绒、缝合和 Z 形钉)限制的元素进行功能性穿厚加固(TTR)的需求日益增长。最近,将大直径 TTR 销钉静态插入加热的预浸料堆栈已被证明是一种可行且稳健的加固工艺,与现有的类似元件尺寸(直径大于 1 毫米)的方法(如固化后钻孔)相比,它能以较低的插入力和较低的丝束损伤提供精确的 TTR 元件位置。本文报告了这些销钉层压板的局部机械性能和失效力学。使用单个静态插入销钉(1.2、1.5 和 2.0 毫米)的层压板大多能保持面内完整性,同时还能局部改善碳纤维-苯并恶嗪层压板的模式 I 分层韧性。拉伸强度基本不受分层抑制所产生的销钉的影响,而杨氏模量则增加了一倍。针 刺层压板的抗压强度明显下降(最多 42%)。层间韧性得到改善,随着销钉直径的增加,峰值韧性被推到裂缝之前。与现有的 TTR 相比,使用静态插入技术生产的插针层压板的面内拉伸性能没有明显下降,这可以扩大可插入材料的范围和形式。Analysis of doubly curved laminated composite shells using hybrid-Trefftz finite element model based on a high order shear deformation theorySubhasankar Dwibedi, M.C. Raydoi:10.1016/j.compstruct.2024.118070利用基于高阶剪切变形理论的混合特雷弗茨有限元模型分析双曲面层压复合材料壳体Static analysis of doubly curved laminated composite shells with rectangular plan form has been carried out using a novel hybrid Trefftz finite element (HTFE) model. A typical higher order shear deformation theory (HSDT) has been used for describing the kinematics of deformations delineating both internal and auxiliary displacement fields. This HSDT allows to derive the system of governing partial differential equations of the single layer equivalent to the element domain. The characteristic functions forming the exact solutions of these homogenous governing equilibrium equations are used as the Trefftz functions. A key aspect of our HTFE strategy is its efficiency in bypassing the use of particular solution of the governing equations. Validation against the exact solutions reveals the precision of this novel HTFE model. The versatility of the Trefftz functions allows them to accommodate a spectrum of geometric configurations, ranging from standard to complex polygonal HTFE designs. The HTFE model for the doubly curved composite shells employing the HSDT marks a significant advancement in the analysis of doubly curved spherical, paraboloid and hyperboloid cross-ply and antisymmetric angle-ply shells.采用新型混合特雷弗茨有限元(HTFE)模型对矩形平面的双曲面层压复合材料壳体进行了静态分析。典型的高阶剪切变形理论(HSDT)被用于描述内部和辅助位移场的变形运动学。该 HSDT 可以推导出与元素域等效的单层偏微分方程系统。形成这些同源控制平衡方程精确解的特征函数被用作特雷弗茨函数。我们的 HTFE 策略的一个关键方面是它能有效地绕过使用治理方程的特定解。根据精确解法进行的验证揭示了这种新型 HTFE 模型的精确性。Trefftz 函数的多功能性使其能够适应从标准到复杂多边形 HTFE 设计的各种几何配置。采用 HSDT 的双曲面复合材料壳体 HTFE 模型标志着在分析双曲面球形、抛物面和双曲面交叉层和非对称角层壳体方面取得了重大进展。Experimental study on the fire resistance of all-composite and hybrid web-core sandwich panels for building floorsM. Proença, M. Garrido, J.R. Correia, J. Sena-Cruzdoi:10.1016/j.compstruct.2024.118071建筑楼板用全复合材料和混合腹板夹芯板的耐火性能实验研究Fibre-reinforced polymer (FRP) composites and polymeric foams used in construction are susceptible to elevated temperatures, but little is known about the behaviour of composite sandwich panels under fire exposure. This paper presents an experimental study on the fire resistance of web-core composite sandwich panels with polyurethane foam infill for building floors. Two panel variants were considered: (i) an all-composite panel, with glass-FRP (GFRP) face sheets and webs; and (ii) a hybrid panel, with an additional fibre reinforced concrete (FRC) top layer. Five full-scale specimens were loaded in a four-point bending configuration, subjected to a constant service load, and subsequently exposed to a standard fire (ISO 834) on their bottom face. The effectiveness of passive fire protection systems, consisting of calcium silicate boards installed either adherent to the panels or forming an air cavity, was assessed. The following features were investigated: (i)temperature progression across the thickness of the panels, (ii)their mechanical response, (iii)failure modes, and (iv)fire resistance. The results obtained indicate that despite the vulnerability of composite sandwich panels to fire, relatively high fire resistances of 44 min and 49 min were obtained for the unprotected web-core all-composite and hybrid variants, respectively. The failure mechanism of the sandwich panels generally involved local compression and in-plane shear failure of the webs. The use of suitable passive fire protections provided significant fire resistance increases of at least 45 min (adherent) and 60 min (with air cavity), allowing to exceed the 90 min threshold.建筑中使用的纤维增强聚合物(FRP)复合材料和聚合泡沫很容易受到高温的影响,但人们对复合夹芯板在火灾中的表现却知之甚少。本文介绍了一项关于带有聚氨酯泡沫填充物的建筑地板用腹板芯复合夹芯板耐火性的实验研究。研究考虑了两种板材变体:(i) 全复合板,包括玻璃纤维增强塑料(GFRP)面板和腹板;(ii) 混合板,包括额外的纤维增强混凝土(FRC)顶层。对五个全尺寸试样进行了四点弯曲加载,使其承受恒定的使用荷载,随后在试样底面进行了标准火灾(ISO 834)试验。评估了被动防火系统的有效性,该系统由安装在面板上的硅酸钙板或形成气腔的硅酸钙板组成。对以下特征进行了研究:(i) 板材厚度上的温度变化;(ii) 板材的机械反应;(iii) 失效模式;(iv) 耐火性。研究结果表明,尽管复合夹芯板易受火灾影响,但无保护腹板芯全复合材料和混合变体的耐火度相对较高,分别为 44 分钟和 49 分钟。夹芯板的破坏机理一般涉及腹板的局部压缩和平面剪切破坏。使用适当的被动防火保护措施可显著提高防火性能,至少可提高 45 分钟(粘附)和 60 分钟(带气腔),从而超过 90 分钟的临界值。Controllable and scalable gradient-driven optimization design for two-dimensional metamaterials based on Deep learningLi Xiao, Zhigang Cao, Haoran Lu, Yuanqiang Caidoi:10.1016/j.compstruct.2024.118072基于深度学习的二维超材料可控、可扩展梯度驱动优化设计A novel gradient-driven rapid optimization design method based on deep learning is proposed to design two-dimensional irregular elastic metamaterial (EMM). We develop a design network comprising a conditional topology generator (TG) and a bandgap predictor (BGP). TG is applied to controllably generate candidate topological structures with geometric constraints, while BGP serves as a surrogate model linking EMM structures with their bandgaps. Utilizing automatic differentiation techniques, the error gradients of design variables are computed on the design network and then passed to gradient-driven optimization algorithms to optimize the design variables until the target bandgap is achieved. The design variables in optimization algorithm are independent of the network’s input features, allowing adaptation to changes in design factors without retraining the network, thereby providing scalability. The testing results demonstrate that the proposed method can efficiently and rapidly design EMM structures, exhibiting significant consistency with target bandgaps. Further comparative analysis reveals that the irregular topological structures enable bandgap broadening, generation of new bandgaps, and band flattening. The proposed method demonstrates significant feasibility and efficiency in the design of irregular EMM structures, and offers practical controllability and scalability.我们提出了一种基于深度学习的梯度驱动快速优化设计方法,用于设计二维不规则弹性超材料(EMM)。我们开发了一个由条件拓扑生成器(TG)和带隙预测器(BGP)组成的设计网络。条件拓扑生成器用于可控地生成具有几何约束的候选拓扑结构,而带隙预测器则用作连接 EMM 结构及其带隙的代理模型。利用自动微分技术,在设计网络上计算设计变量的误差梯度,然后将其传递给梯度驱动优化算法,以优化设计变量,直至达到目标带隙。优化算法中的设计变量与网络的输入特征无关,因此无需重新训练网络即可适应设计因素的变化,从而提供了可扩展性。测试结果表明,所提出的方法可以高效、快速地设计 EMM 结构,并与目标带隙表现出明显的一致性。进一步的比较分析表明,不规则拓扑结构能够拓宽带隙、产生新带隙和实现带平坦化。所提出的方法证明了设计不规则 EMM 结构的显著可行性和效率,并提供了实用的可控性和可扩展性。Artificial neural network prediction of transverse modulus in humid conditions for randomly distributed unidirectional fibre reinforced composites: A micromechanics approachK. Aghabalaei Baghaei, S.A. Hadighehdoi:10.1016/j.compstruct.2024.118073人工神经网络预测随机分布单向纤维增强复合材料在潮湿条件下的横向模量:微观力学方法This paper proposes an innovative micromechanics-based artificial neural network (ANN) method to efficiently investigate the transverse modulus of unidirectional fibre/epoxy composites under humid conditions. In this research, a novel approach is developed to establish relations between the geometrical, mechanical, and environmental properties of the microstructure and the material’s performance under transverse tension. A framework is developed to artificially generate periodic representative volume elements (RVEs) while taking into account the interphase region between fibre and matrix. The RVEs are analysed by the finite element method to obtain the transverse moduli of composites. Two-point correlation functions and principal component analysis techniques are applied to extract and compress statistical information from microstructure images. A database establishment framework is developed to create three batches of data with 1000, 2000, and 3000 sizes. An ANN-based prediction framework is developed by integrating 10-fold cross validation and Bayesian optimisation to optimise the neural network architecture and establish an efficient structure-property linkage under the influence of humid conditions. The prediction results demonstrate the efficiency of ANN in mapping microstructural data to effective transverse modulus. A parametric study by ANN reveals the role of microstructure geometrical features and humid environmental parameters on the transverse performance of the composite.本文提出了一种基于微机械学的创新型人工神经网络(ANN)方法,用于有效研究单向纤维/环氧复合材料在潮湿条件下的横向模量。在这项研究中,开发了一种新方法来建立微结构的几何、机械和环境属性与材料在横向拉伸下的性能之间的关系。在考虑到纤维与基体之间的相间区域的同时,还开发了一个框架来人为生成周期性的代表性体积元素(RVE)。通过有限元法对 RVE 进行分析,从而获得复合材料的横向模量。应用两点相关函数和主成分分析技术从微观结构图像中提取和压缩统计信息。开发了一个数据库建立框架,以创建 1000、2000 和 3000 大小的三批数据。通过整合 10 倍交叉验证和贝叶斯优化,开发了基于神经网络的预测框架,以优化神经网络结构,并在潮湿条件影响下建立有效的结构-属性联系。预测结果表明了神经网络在将微观结构数据映射到有效横向模量方面的效率。利用神经网络进行的参数研究揭示了微观结构几何特征和潮湿环境参数对复合材料横向性能的影响。3D compression-twist lattice metamaterials for surface reconfigurability of future architectureHan Yan, Yi Zhang, Xing Chi Teng, Wei Zhong Jiang, Yi Min Xie, Wen Wang Wu, Wei Qiu Chen, Chuan Zeng Zhang, Xin Rendoi:10.1016/j.compstruct.2024.118075用于未来建筑表面可重构性的三维压缩扭转晶格超材料Metamaterials refer to a class of materials with special properties, whose characteristics mainly come from the microstructures designed artificially. Among them, those metamaterials with tunable shape and mechanical properties under external stimuli provide a new inspiration for the design of the multifunctional structures. This work deals with the three-dimensional (3D) compression-twist lattice metamaterials, studies the surface reconfigurability under external forces, and reveals the torsion-bending coupling (TBC) effect of the special metamaterials. To explain the main characteristics of the TBC effect, the deformation mechanism of the metamaterials is analyzed. Combining the finite element method (FEM) and the spherical fitting algorithm, the relationship between the bending angle and the load of the metamaterials after deformation is analyzed and verified by experiments. Finally, a metamaterial module that could be freely transformed between planar and spherical surfaces is envisaged. A faster and greener solution is proposed for the construction of curved surfaces of engineering structures in the future, which promotes the subsequent applications of metamaterials to engineering practice.超材料是指一类具有特殊性能的材料,其特性主要来自人工设计的微结构。其中,在外部刺 激下具有可调形状和机械特性的超材料为多功能结构的设计提供了新的灵感。本研究以三维压缩扭转晶格超材料为对象,研究其在外力作用下的表面可重构性,并揭示特殊超材料的扭转弯曲耦合(TBC)效应。为了解释 TBC 效应的主要特征,分析了超材料的变形机理。结合有限元法(FEM)和球形拟合算法,分析了超材料变形后的弯曲角度与载荷之间的关系,并通过实验进行了验证。最后,设想了一种可在平面和球面之间自由转换的超材料模块。这为未来建造工程结构的曲面提出了一个更快、更环保的解决方案,从而促进了超材料在工程实践中的后续应用。来源:复合材料力学仿真Composites FEM

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