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【新文速递】2024年11月7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 1 篇,Journal of the Mechanics and Physics of Solids 1 篇,International Journal of Plasticity 2 篇,Thin-Walled Structures 7 篇

International Journal of Solids and Structures

Investigation on dynamic impact behavior of bighorn sheep’s horn

Emre Palta, Howie Fang, Qian Wang, Zheng Li

doi:10.1016/j.ijsolstr.2024.113133

大角羊角的动态碰撞特性研究

The horn of the bighorn sheep is composed of keratin-based biological material that has a tubule-lamella structure, which gives it anisotropic hardening properties under impact loading. This paper aims to investigate the energy dissipation mechanisms inherent in bighorn sheep horns by developing a numerical material model that accounts for the horn’s anisotropic features and strain-rate effects. To this end, a transversely isotropic constitutive model, which includes both anisotropic hardening and strain-rate effects, was formulated to accurately predict the mechanical behavior of bighorn sheep horns. Material characterization was conducted through uniaxial compression tests that were conducted under quasi-static and dynamic conditions. The developed constitutive model was implemented into LS-Dyna via a user-defined material subroutine and was validated against empirical data. The validated numerical model was used to investigate the horn’s mechanical responses under dynamic loading conditions. The paper focused on impact energy dissipation mechanisms, including energy absorption and transition, stress distribution, and displacement wave propagation. The insights gained from this paper are expected to significantly contribute to the development of novel artificial materials with enhanced energy absorption and impact mitigation properties.

大角羊的角是由角蛋白为基础的生物材料,具有管片状结构,使其在冲击载荷下具有各向异性硬化特性。本文旨在通过建立考虑大角羊角各向异性特征和应变率效应的数值材料模型,研究大角羊角固有的能量耗散机制。为此,建立了考虑各向异性硬化和应变率效应的横向各向同性本构模型,以准确预测大角羊角的力学行为。通过准静态和动态条件下的单轴压缩试验进行材料表征。通过用户自定义的材料子程序在LS-Dyna中实现了所开发的本构模型,并与经验数据进行了验证。利用验证后的数值模型,研究了动载荷条件下变幅杆的力学响应。重点研究了冲击能量耗散机制,包括能量吸收和转移、应力分布和位移波传播。从本文中获得的见解预计将大大有助于开发具有增强能量吸收和减轻冲击性能的新型人工材料。


Journal of the Mechanics and Physics of Solids

Damage-induced energy dissipation in artificial soft tissues

W.K. Sun, B.B. Yin, K.M. Liew

doi:10.1016/j.jmps.2024.105933

人造软组织损伤引起的能量耗散

A systematic understanding of the toughening and self-healing mechanisms of artificial soft tissues is crucial for advancing their robust application in biomedical engineering. However, current models predominantly possess a phenomenological nature, often devoid of micromechanical intricacies and quantitative correlation between microstructure damage and macroscopic energy dissipation. To bridge this gap, we propose a novel energy dissipation mechanism-motivated network model that incorporates three unique physical ingredients with sound theoretical basis for the first time. These innovated features include the bond percolation-mediated network density and stiffness, the damage-induced energy dissipation and stress softening, and the entropic elasticity for the highly stretchable second network. The validity of this model was examined by implementing it within a meshfree peridynamic framework for artificial soft tissues subjected to simple tension and pure shear tests. We quantitatively correlated the dissipation with the network damage to reveal the effects of network density, the breaking stretch dispersion and the stiffness ratio. Our findings highlighted that the inhomogeneity and dispersion of materials properties play significant roles in the controllable progressive damage and dissipation, thereby offering valuable guidance for designing tougher artificial soft tissues. By reactivating the failed network, we further successfully captured the self-healing behaviors of artificial soft tissues. Our work provides an inspiring modeling framework for studying toughening mechanisms of artificial soft tissues.

系统地了解人造软组织的增韧和自愈机制对于推进其在生物医学工程中的强大应用至关重要。然而,目前的模型主要具有现象学性质,往往缺乏微观力学的复杂性和微观结构损伤与宏观能量耗散之间的定量关联。为了弥补这一差距,我们首次提出了一种新的能量耗散机制驱动的网络模型,该模型包含了三种独特的物理成分,具有良好的理论基础。这些创新的特征包括键渗透介导的网络密度和刚度,损伤引起的能量耗散和应力软化,以及高度可拉伸的第二网络的熵弹性。通过对人工软组织进行简单拉伸和纯剪切试验的无网格周动力框架,验证了该模型的有效性。我们定量地将耗散与网络损伤进行了关联,揭示了网络密度、断裂拉伸色散和刚度比对网络耗散的影响。研究结果表明,材料性能的非均匀性和分散性在可控制的渐进损伤和耗散中起着重要作用,从而为设计更坚韧的人造软组织提供了有价值的指导。通过重新激活失败的网络,我们进一步成功地捕获了人工软组织的自愈行为。我们的工作为研究人造软组织的增韧机制提供了一个鼓舞人心的建模框架。


International Journal of Plasticity

Towards extraordinary strength-ductility synergy in pure Mg via dislocation transmutation

Liuyong He, Jiang Zheng, Mengning Xu, Tianjiao Li, Dongdi Yin, Bin Jiang, Fusheng Pan, Hao Zhou

doi:10.1016/j.ijplas.2024.104160

通过位错嬗变在纯Mg中实现非凡的强度-延展性协同作用

Navigating the strength-ductility trade-off has been a persistent challenge in Mg alloys. Here, we address this issue through a novel multiple-direction pre-deformation at room temperature that introduces a high density of <c+a> dislocations into pure Mg via dislocation transmutation. This approach achieves a remarkable enhancement in the strength-ductility synergy, increasing the yield strength from 87.6 MPa to 156.6 MPa and improving elongation to failure from 7.7% to 17.6%. In general, introducing a high-density <c+a> dislocations in Mg alloys have been difficult due to the high CRSS at room temperature. Our findings reveal that extension twinning can act as a “dislocation converter,” transforming basal dislocations in the matrix into <c+a> dislocations within twins. Intensive basal dislocations were induced in pure Mg through pre-tension and subsequently transformed into <c+a> dislocations via extension twinning during compression. This process led to a substantial number of <c+a> dislocations and I1 stacking faults, contributing to the enhanced strength. The high density of <c+a> dislocations, combined with I1 stacking faults and a reduced c/a ratio within twins, enhances the activity of pyramidal <c+a> slip, thereby significantly improving ductility. This dislocation transmutation strategy offers a promising way for producing strength-ductility synergy in Mg alloys.

在强度和延展性之间进行权衡一直是镁合金面临的挑战。在这里,我们通过一种在室温下的新型多方向预变形来解决这个问题,该变形通过位错嬗变将高密度的<c+a>位错引入纯Mg。该方法显著增强了强度-塑性协同效应,使屈服强度从87.6 MPa提高到156.6 MPa,破坏伸长率从7.7%提高到17.6%。一般来说,由于室温下的高CRSS,在镁合金中引入高密度<c+a>位错是困难的。我们的研究结果表明,延伸孪晶可以作为“位错转换器”,将基体中的基底位错转化为孪晶中的<c+a>位错。在纯Mg中,通过预拉伸诱导了密集的基底位错,随后在压缩过程中通过扩展孪晶转化为<c+a>位错。这一过程导致大量的<c+a>位错和I1层错,有助于提高强度。高密度的<c+a>位错,结合I1层错和孪晶内减小的c/a比,增强了锥体<c+a>滑移的活动性,从而显著提高了塑性。这种位错嬗变策略为镁合金强度-塑性协同效应的产生提供了一条有希望的途径。


Exceptional tensile ductility and strength of a BCC structure CLAM steel with lamellar grains at 77 kelvin

Jinhua Zhou, Jing Wang, Jungang Ren, Robert O. Ritchie, Zuncheng Wang, Yuchao Wu, Zhufeng He, Xin Wang, Ying Fu, Yifu Jiang, Lin Wang, Xiaowei Yin

doi:10.1016/j.ijplas.2024.104161

具有77开尔文层状晶粒的BCC结构CLAM钢的优异拉伸延展性和强度

The low-temperature tensile brittleness of body-centered cubic (BCC) metals and alloys can seriously compromise their service applications. In this study, we prepared a BCC structured China low activation martensitic steel (CLAM) steel with lamellar grains by regulating the rolling and heat-treatment processes, successfully reversing the decreasing trend of ductility in the steel with decrease in temperature. Compared with current face-centered cubic (FCC) structural steels and high-entropy alloys, the lamellar grained CLAM steel exhibits an excellent synergy of strength and ductility at 77K, but with lower raw material costs. The superior low temperature ductility of the lamellar grained steel can be attributed to an increase in grain strength at low temperatures which promotes the propagation of layered tearing cracks; this in turn leads to a significant increase in the necking area of the steel, thereby compensating for the decrease in ductility. We conclude that our lamellar grain structures can be utilized to significantly enhance the low-temperature tensile ductility of BCC metals and alloys, thereby expanding their service range to cryogenic temperatures.

体心立方(BCC)金属和合金的低温拉伸脆性严重影响其使用。本研究通过调整轧制工艺和热处理工艺,制备了具有层状晶粒的BCC组织中国低活化马氏体钢(CLAM),成功扭转了该钢随温度降低而塑性下降的趋势。与现有的面心立方(FCC)结构钢和高熵合金相比,层状晶状CLAM钢在77K时表现出良好的强度和延展性协同作用,但原材料成本较低。层状晶钢具有较好的低温延展性,主要是由于在低温条件下晶粒强度的提高促进了层状撕裂裂纹的扩展;这反过来又导致钢的颈缩面积显著增加,从而补偿了延展性的降低。我们的结论是,我们的层状晶粒结构可以用来显著提高BCC金属和合金的低温拉伸延展性,从而扩大它们的使用范围到低温。


Thin-Walled Structures

Web Shear Buckling of Steel-Concrete Composite Girders – Advanced Numerical Analysis

Mehmed Numanović, Markus Knobloch

doi:10.1016/j.tws.2024.112671

钢-混凝土组合梁腹板剪切屈曲的高级数值分析

Load-bearing capacity of plate girders, often used in design of bridges and high-rise buildings, is limited by the shear capacity of connected slender plate elements subjected to shear buckling. To quantify this, experimental investigations on five large-scale steel and steel-concrete composite plate girders loaded solely in shear, with a minimal influence of bending moments, have been conducted and evaluated. In this paper, the phenomenon of web shear buckling is investigated within the numerical analysis using the ABAQUS Software. An advanced numerical model has been developed and results validated against existing experimental findings. One of the focal points of this study represents the methodology of developing such a comprehensive numerical model, implementation of suitable analysis procedures, material models, boundary conditions, finite elements and interactions, in order to correctly replicate the observed response in the tests. In addition, case studies tackling the influence of web slenderness, aspect ratio, initial imperfections, shear connection and concrete classes on the structural-mechanical behavior of steel-concrete composite girders in shear as well as the applicability and suitability of the existing analytical model are also presented and analyzed.

通常用于桥梁和高层建筑设计的板梁,其承载能力受到受剪切屈曲作用的细长板单元的剪切能力的限制。为了量化这一点,对五个大型钢-钢-混凝土组合板梁进行了试验研究,仅受剪切作用,弯矩影响最小,并进行了评估。本文利用ABAQUS软件对腹板剪切屈曲现象进行了数值分析。建立了一个先进的数值模型,并与现有的实验结果进行了验证。本研究的重点之一是开发这样一个全面的数值模型的方法,实施适当的分析程序、材料模型、边界条件、有限元和相互作用,以便正确地复 制试验中观察到的响应。此外,还对腹板长细比、纵横比、初始缺陷、受剪连接和混凝土等级对钢-混凝土组合梁受剪结构力学性能的影响以及现有分析模型的适用性和适宜性进行了实例分析。


Shock mitigation and failure mechanism of copper foam/paraffin phase change reinforced composites

Jingjing Song, Yuliang Lin, Minzu Liang, Wen Liang, Jiakai Guo, Yuwu Zhang

doi:10.1016/j.tws.2024.112673

泡沫铜/石蜡相变增强复合材料的减震破坏机理

Copper foam/paraffin phase change reinforced composites (CPPC) were fabricated using vacuum immersion technology to address the pressing need for phase change reinforced composite applications. Experiments were conducted to explore the influence of strain rate and relative density of the matrix material on the mechanical properties of the CPPC under both quasi-static and dynamic conditions. A 3D-Voronoi model of the CPPC was developed with randomly varying relative density, based on real porous metal foam and utilizing graphical parametric design tools. The mechanical behavior of the CPPC under impact loading was studied, focusing on deformation, energy absorption, and damage mechanisms. Comparison and analysis of stress-strain curves and deformation modes were performed using experimental and modeling data. The shear failure modes of CPPC under quasi-static compression include 'X-shaped fracture,' 'blocky spalling,' or '45° parallel fracture,' depending on the relative density of the copper foam matrix. The addition of paraffin effectively improved the energy-absorbing properties of copper foam. As the relative density of the copper foam matrix increased, the enhancement in energy absorption became more pronounced, while the improvement in modulus and yield strength decreased. The composite exhibited an 83% increase in specific energy absorption compared to copper foam alone, with the paraffin filler absorbing 69% of the total energy during impact loading. The CPPC acted as a mechanical filter through stress wave reflection and transmission attenuation. The investigation into the shock mitigation and failure mechanisms of CPPC could offer valuable insights for the design of functional composites. Furthermore, it could inspire the creation of impact-resistant and heat dissipation structures for electronic devices.

针对相变增强复合材料应用的迫切需要,采用真空浸泡技术制备了泡沫铜/石蜡相变增强复合材料(CPPC)。在准静态和动态两种条件下,研究了应变速率和基体材料相对密度对CPPC力学性能的影响。基于真实多孔金属泡沫,利用图形参数化设计工具,建立了相对密度随机变化的CPPC 3D-Voronoi模型。研究了CPPC在冲击载荷作用下的力学行为,重点研究了CPPC的变形、能量吸收和损伤机理。利用实验数据和模型数据对应力-应变曲线和变形模式进行了对比分析。根据泡沫铜基体的相对密度,CPPC在准静态压缩下的剪切破坏模式可分为“x形断裂”、“块状剥落”或“45°平行断裂”。石蜡的加入有效地改善了泡沫铜的吸能性能。随着泡沫铜基体相对密度的增加,吸能增强更加明显,而模量和屈服强度的提高幅度减小。与单独的泡沫铜相比,该复合材料的比能量吸收增加了83%,其中石蜡填料在冲击加载时吸收了总能量的69%。CPPC通过应力波反射和透射衰减起到机械滤光器的作用。对CPPC减震失效机理的研究可为功能复合材料的设计提供有价值的见解。此外,它可以激发电子设备的抗冲击和散热结构的创造。


A comprehensive study of beam modal functions in the free vibration analysis of cylindrical shells: critical examination on the applicability to the clamped-free boundary condition

Ganghui Xu, Changsheng Zhu

doi:10.1016/j.tws.2024.112674

圆柱壳自由振动分析中梁模态函数的综合研究:对无夹紧边界条件适用性的关键检验

Over the past few decades, approximate methods that can provide solutions of sufficient accuracy have received considerable attention in the free vibration analysis of cylindrical shells, where a great deal of studies adopted the beam modal functions as the trial functions for the axial mode shapes of cylindrical shells. Nevertheless, most studies were restricted to the application of single term beam modal function and failed to simulate elastic boundary conditions of cylindrical shells, while the accuracy of the corresponding methods has recently sparked significant controversy, especially for cylindrical shells under the clamped-free boundary condition. This paper presents a comparative study of three forms of beam modal functions in the free vibration analysis of cylindrical shells, one of which is proposed for the first time to simulate elastic boundary conditions of cylindrical shells. A unified model is developed using the general Rayleigh-Ritz method, incorporating the breathing modes with circumferential orders being zero, and four types of commonly used thin shell theories, namely the Donnell, Reissner, Love, and Sanders theories. From both perspectives of natural frequencies and mode shapes, numerical results are validated by comparison with those existing in the literature and those calculated from the finite element method (FEM). The results not only clarify the distinction of different forms of beam modal functions used in the Rayleigh-Ritz method, but also provide explanations for the controversy raised in recent studies. Furthermore, the unified formulations can be extended to vibration analysis of various forms of shell structures, and can also be helpful to the vibration analysis of beams and plates with elastic boundary conditions.

近几十年来,能够提供足够精度解的近似方法在圆柱壳的自由振动分析中受到了相当大的重视,其中大量的研究采用梁模态函数作为圆柱壳轴向模态振型的试函数。然而,大多数研究仅限于应用单项梁模态函数,未能模拟圆柱壳的弹性边界条件,而相应方法的准确性近年来引起了很大的争议,特别是对无夹固边界条件下的圆柱壳。本文对圆柱壳自由振动分析中的三种梁模态函数形式进行了比较研究,首次提出了一种用于模拟圆柱壳弹性边界条件的梁模态函数形式。采用一般的瑞利-里兹方法,将周向阶数为零的呼吸模式与Donnell、Reissner、Love和Sanders四种常用的薄壳理论相结合,建立了统一的模型。从固有频率和模态振型两方面对数值结果进行了验证,并与已有文献和有限元法计算结果进行了比较。研究结果不仅澄清了Rayleigh-Ritz方法中不同形式梁模态函数的区别,而且对近年来研究中出现的争议提供了解释。统一的公式可以推广到各种形式的壳结构的振动分析中,也可以用于具有弹性边界条件的梁和板的振动分析。


Physics-informed radial basis networks for force finding of cable domes

Mingliang Zhu, Jin Wang, Jiamin Guo

doi:10.1016/j.tws.2024.112675

用于索穹顶受力测量的物理信息径向基网络

The stiffness of cable dome structures is entirely derived from the prestress in their cables and struts, making force-finding a critical step in their design. However, traditional force-finding methods are often complex to implement and have limited applicability. To address these challenges, this paper establishes a general force-finding framework for cable domes based on physics-informed radial basis networks (PIRBN), utilizing neural network techniques to achieve an efficient and reliable force-finding process. Additionally, a loss function is derived that incorporates the physical characteristics of cable domes from the perspective of structural stiffness. Case studies on three types of cable domes were conducted, and the hyperparameter tuning of the network model was simplified using the Optuna hyperparameter optimization method. The results show that PIRBN is suitable for force-finding analysis in both single and multiple prestress mode cable domes, considering the effects of external loads, and provides high computational efficiency and broad applicability.

索穹顶结构的刚度完全来源于其索和支柱的预应力,因此求力是其设计的关键步骤。然而,传统的测力方法往往是复杂的实现和有限的适用性。为了解决这些挑战,本文建立了一个基于物理信息径向基网络(PIRBN)的电缆圆顶通用力查找框架,利用神经网络技术实现高效可靠的力查找过程。此外,从结构刚度的角度,导出了一个包含索穹顶物理特性的损失函数。以三种类型的电缆穹顶为例,采用Optuna超参数优化方法简化了网络模型的超参数整定。结果表明,PIRBN在考虑外荷载影响的情况下,适用于单预应力模式和多预应力模式索穹顶受力分析,计算效率高,适用性广。


Self-healing effect on the impact-resistance of hybrid stitch toughening CFRP composites: Experimental and numerical study

Zhenzhen Zhang, Yutong Liu, Ying Tie, Yuliang Hou, Cheng Li

doi:10.1016/j.tws.2024.112635

复合缝增韧CFRP复合材料抗冲击性能的自愈效应:实验与数值研究

The self-healing effect on the impact-resistance has been investigated for hybrid stitch toughening CFRP composites using multiscale modeling. The stitches made of the healing agent, poly ethylene-co-methacrylic acid (EMAA), facilitate the repair of delamination damages via a self-healing process. The other stitches, fabricated from carbon fiber, contribute to the enhancement of interlaminar toughness. Considering the local structural features adjacent to the stitches, an equivalent fiber-embedded laminate (EFEL) cell is established to characterize the mesoscale behavior. A modified constitutive model is developed to accurately describe the deformation modes of the EFEL cell. Subsequently, a macroscale model is constructed by directly extending the EFEL cells. The self-healing of the impact-resistance is numerically explored through multiple low-velocity impact (LVI) tests. The proposed modeling approach enables a prediction error less than 8.4% and the computation time of approximately 17.3 h (1036 min), demonstrating the high accuracy and efficiency. After the self-healing process, the peak impact forces of the LVI specimens increase, while decreases in absorbed energy are observed. Moreover, the healed specimens exhibit fewer damaged elements and a smoother damaged surface compared with the unhealed ones. It demonstrates that the EMAA healing agent possesses the capability to improve the impact-resistance of hybrid stitch toughening CFRP composites.

采用多尺度模型研究了复合针状增韧CFRP复合材料的自愈效应。由愈合剂——聚乙烯-甲基丙烯酸(EMAA)制成的缝线,通过自愈过程促进分层损伤的修复。其他缝线由碳纤维制成,有助于增强层间韧性。考虑到缝线附近的局部结构特征,建立了等效的纤维嵌入层压(EFEL)单元来表征缝线的中尺度行为。提出了一种修正的本构模型,以准确地描述电光放电单元的变形模式。然后,通过直接扩展EFEL单元,构建了宏观尺度模型。通过多次低速冲击(LVI)试验,数值探讨了抗冲击的自愈性。该建模方法预测误差小于8.4%,计算时间约为17.3 h (1036 min),具有较高的精度和效率。自愈过程后,LVI试样的峰值冲击力增大,而吸收能量减小。与未愈合的试件相比,愈合后试件的损伤元素较少,损伤表面更光滑。结果表明,EMAA愈合剂具有提高复合针状增韧CFRP复合材料抗冲击性能的能力。


Shear performance prediction for corrugated steel web girders based on machine-learning algorithms

Yong Liu, Wei Ji, Jieqi Li, ShiBo Liu, Wenjuan Yang

doi:10.1016/j.tws.2024.112668

基于机器学习算法的波纹钢腹板梁抗剪性能预测

This study aimed to predict the shear strength of corrugated steel web girders (CSWGs) by developing a new method based on four machine-learning (ML) algorithms, namely the support vector machine, artificial neural network, random forest, and XGBoost. Based on the acquired experimental and numerical data, a database containing 552 samples was constructed to train and test the ML models. A five-fold cross-validation approach was adopted during training to prevent model overfitting. A RandomizedSearchCV was used to optimize the hyperparameters of each model. The performance of the trained models was evaluated using four performance metrics, and the results revealed that the coefficients of determination (R2) of all ML models exceeded 0.97 when used on both training and validation sets, demonstrating the excellent performance of the ML models in predicting the shear strength of CSWGs. Additionally, the implemented ML models outperformed existing design codes and empirical formulae. The XGBoost model yielded the best prediction results with an R2 of 0.999, mean absolute error of 44.98 kN, root-mean-square error of 66.67 kN, and mean absolute percentage error of 2.1 %. By using the Shapley additive explanation to derive a visual, quantitative explanation of the XGBoost model, the yield strength, web thickness, and web height were identified as the most critical factors affecting the shear strength of CSWGs, and their average absolute Shapley values accounted for approximately 91.45 % of the total value. The ML models implemented in this study provide a promising new approach for pre-designing and verifying the stability of CSWGs.

基于支持向量机(support vector machine)、人工神经网络(artificial neural network)、随机森林(random forest)和XGBoost四种机器学习算法,对波纹钢腹板梁(CSWGs)的抗剪强度进行预测。基于获得的实验数据和数值数据,构建了包含552个样本的数据库,对ML模型进行训练和测试。在训练过程中采用五重交叉验证方法来防止模型过拟合。使用RandomizedSearchCV对每个模型的超参数进行优化。采用4个性能指标对训练模型的性能进行评价,结果表明,在训练集和验证集上使用的ML模型的决定系数(R2)均超过0.97,表明ML模型在预测cswg抗剪强度方面具有良好的性能。此外,实现的ML模型优于现有的设计规范和经验公式。XGBoost模型预测结果最佳,R2为0.999,平均绝对误差为44.98 kN,均方根误差为66.67 kN,平均绝对百分比误差为2.1%。利用Shapley加性解释对XGBoost模型进行可视化、定量的解释,确定了屈服强度、腹板厚度和腹板高度是影响cswg抗剪强度的最关键因素,其平均绝对Shapley值约占总量的91.45%。本研究中实现的ML模型为cswg的预设计和稳定性验证提供了一种有希望的新方法。


Weak form quadrature shell elements based on absolute nodal coordinate formulation

Zixuan He, Huayi Li, Hongzhi Zhong

doi:10.1016/j.tws.2024.112670

基于绝对节点坐标公式的弱形式正交壳单元

Weak form quadrature elements for moderately thick shells with arbitrary initial configurations are developed under the framework of continuum mechanics and the absolute nodal coordinate formulation (ANCF). Locking problems of shell analysis are discussed. Nonlinear analysis of various shell structures is conducted. The joint constraint equations for shells with discontinuous slopes are established. Five examples encompassing static and dynamic shell analysis, post-buckling analysis of shells, as well as analysis of shells with discontinuous mid-surface slopes are examined to assess the performance of the proposed elements. Satisfactory results are obtained, validating the efficacy of the proposed elements.

在连续介质力学和绝对节点坐标公式的框架下,建立了具有任意初始构型的中厚壳的弱形式正交单元。讨论了壳体分析中的锁定问题。对各种壳结构进行了非线性分析。建立了具有不连续斜率的壳的联合约束方程。五个例子包括静力和动力壳分析,壳的后屈曲分析,以及具有不连续中表面斜率的壳的分析,以评估所提出的单元的性能。得到了满意的结果,验证了所提出元件的有效性。




来源:复合材料力学仿真Composites FEM
ACTMechanicalLS-DYNAAdditiveSystem振动断裂复合材料碰撞非线性通用建筑电子ECAD裂纹参数优化理论材料
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【新文速递】2024年5月24日复合材料SCI期刊最新文章

今日更新:Composite Structures 3 篇,Composites Part A: Applied Science and Manufacturing 5 篇,Composites Science and Technology 2 篇Composite StructuresNew insights into folding tape-springTian-Wei Liu, Jiang-Bo Bai, Nicholas Fantuzzidoi:10.1016/j.compstruct.2024.118225折叠带弹簧的新见解The tape-spring is widely used in aerospace, mechanical, and civil engineering due to its unique mechanical properties and compact size. This paper aims to establish a new analytical model to more accurately predict the folding behavior of the tape-spring, including the geometric configuration, folding moment versus longitudinal curvature curve, peak moment, and propagation moment. This model comprehensively considers the influence of stretching strain energy and bending strain energy on the total strain energy, and determines the folding behavior of the tape-spring through the minimum energy principle. The proposed analytical model was compared with Wuest’s model, Yee’s model, and Yao’s model. Experiments of tape-springs made from two different materials were utilized for validation. The study shows that the proposed model has the highest prediction accuracy compared with the classical models, with the error of approximately 10%. The reason for the significant difference in the prediction results between the proposed model and Yao’s model was given, and the relationship between stretching strain energy and bending strain energy during the folding process of the tape-spring was analyzed. The proposed model has broader applicability than classical models and provides new insights and solutions for accurate prediction of the folding behavior of the tape-spring.带式弹簧以其独特的力学性能和紧凑的尺寸在航空航天、机械和土木工程中得到广泛应用。本文旨在建立一个新的解析模型,以更准确地预测带式弹簧的折叠行为,包括几何构型、折叠弯矩与纵向曲率曲线、峰值弯矩和传播弯矩。该模型综合考虑了拉伸应变能和弯曲应变能对总应变能的影响,通过最小能量原理确定了带式弹簧的折叠行为。将提出的分析模型与Wuest的模型、Yee的模型和Yao的模型进行比较。用两种不同材料制成的带式弹簧进行了实验验证。研究表明,与经典模型相比,该模型具有最高的预测精度,误差约为10%。给出了该模型与Yao模型预测结果存在显著差异的原因,分析了带式弹簧折叠过程中拉伸应变能与弯曲应变能之间的关系。该模型具有比传统模型更广泛的适用性,为准确预测带式弹簧的折叠行为提供了新的见解和解决方案。Multi-feature parallel topology optimization of fiber-reinforced coated structures based on a dual variable scale filtering methodXuefei Yang, Liang Gao, Hao Lidoi:10.1016/j.compstruct.2024.118227基于双变尺度滤波的纤维增强涂层结构多特征并行拓扑优化Due to their outstanding mechanical properties, fiber-reinforced polymer composite (FRPC) structures have become a prominent research topic. Yet, to surpass existing performance limits, their design potential should be expanded beyond conventional empirical methods. Moreover, because of the high manufacturing costs, the protection of FRPC structures should be considered in the design phase to extend their service life. In this paper, we introduce an innovative configuration wherein metal coatings are strategically applied to the surfaces of FRPC structures. This technique aims to protect the internal matrix and fiber materials, and to inhibit the interlaminar delamination of composite laminates. Then, a corresponding full-scale topology optimization framework is built based on a density-based method. The coating, matrix, and fiber materials are considered collectively, avoiding issues such as excessive computation, non-convex optimization, and fiber discontinuity. Furthermore, a dual variable scale filtering (DVSF) method and its simplified scheme are presented to optimize coating thickness based on the physical information obtained from finite element analysis. Meanwhile, the co-evolution of solid topology and fiber morphology, driven by algorithms, facilitates the parallel optimization of multiple geometric features. Several typical examples, including wing ribs, are provided to illustrate the effectiveness and superiority of our approach, highlighting its engineering relevance.由于其优异的力学性能,纤维增强聚合物复合材料(FRPC)结构已成为一个突出的研究课题。然而,为了超越现有的性能限制,它们的设计潜力应该超越传统的经验方法。此外,由于制造成本高,在设计阶段应考虑对FRPC结构的保护,以延长其使用寿命。在本文中,我们介绍了一种创新的配置,其中金属涂层战略性地应用于FRPC结构的表面。该技术旨在保护内部基体和纤维材料,抑制复合材料层间分层。然后,基于基于密度的方法构建了相应的全尺寸拓扑优化框架。涂层、基体和纤维材料被综合考虑,避免了过多的计算、非凸优化和纤维不连续等问题。在此基础上,提出了基于有限元物理信息的双变尺度滤波(DVSF)方法及其简化方案来优化涂层厚度。同时,在算法的驱动下,固体拓扑和光纤形态的协同演化为多个几何特征的并行优化提供了便利。提供了几个典型的例子,包括翼肋,以说明我们的方法的有效性和优越性,突出其工程相关性。Mechanical behavior of STF impregnation and anti-impact performances of Kevlar and UHMPWEF fabric impregnationsEnling Tang, Hongrun Tan, Ruizhi Wang, Chuang Chen, Yafei Han, Mengzhou Chang, Kai Guo, Liping Hedoi:10.1016/j.compstruct.2024.118228STF浸渍的力学行为及Kevlar和UHMPWEF织物浸渍的抗冲击性能STF-impregnated Kevlar and ultra-high molecular weight polyethylene (UHMWPEF) fabric-impregnated bodies were prepared by using mass fraction of 34 % SiO2 with a particle size of 100 nm and PEG400 as dispersion and dispersant, respectively. When two kinds of fiber fabrics were impregnated by STF, the tensile, single fiber pull-out and single fiber tensile loads of Kevlar fabric-impregnated increased 26.63 %, 155.55 %, and 98.64 %, respectively. However, the tensile load, monofilament pull-out load and monofilament tensile load of the UHMWPEF fabric-impregnated body increased 100.14 %, 729.03 % and 51.61 %, respectively. Kevlar fiber fabric impregnated by ultrasonic vibration and smearing STF absorbs more steel projectile’s kinetic energies of 52.3 % and 27.43 % than that of the original fiber fabric, respectively. UHMPWEF fabric impregnated by using ultrasonic vibration and smearing increased 65.56 % and 47.73 % than the original fabric absorbing steel projectile’s kinetic energy. Based on the Scanning Electron Microscope (SEM) observation of the fiber fabric surface, it was found that the connection between the fibers was significantly strengthened after the STF impregnation treatment. When the fabric was subjected to impact load, STF played an important role in transmitting load and increasing friction.采用质量分数为34 %、粒径为100 nm的SiO2和PEG400分别作为分散剂和分散剂,制备了stf浸渍凯夫拉纤维和超高分子量聚乙烯(UHMWPEF)织物浸渍体。两种纤维织物经STF浸渍后,其拉伸载荷、单纤维拉拔载荷和单纤维拉伸载荷分别提高26.63 %、155.55 %和98.64 %。而UHMWPEF织物浸渍体的拉伸载荷、单丝拉拔载荷和单丝拉伸载荷分别提高了100.14 %、729.03 %和51.61 %。超声振动浸渍和涂抹STF的Kevlar纤维织物比原纤维织物吸收钢弹的动能分别增加52.3% %和27.43% %。超声振动和涂布浸渍后的超高强度wef织物对钢弹动能的吸收比原织物提高了65.56 %和47.73 %。通过对纤维织物表面的扫描电镜(SEM)观察发现,经STF浸渍处理后,纤维之间的连接明显加强。当织物受到冲击载荷时,STF在传递载荷和增加摩擦方面发挥了重要作用。Composites Part A: Applied Science and ManufacturingToughening of self-reinforced PLA films using PLA nanofiber mats and oriented PLA tapes as interlayersGuiling Niu, Yinping Tao, Rongmin Zhang, Xin Feng, Hua Deng, Musu Ren, Jinliang Sun, Ton Peijsdoi:10.1016/j.compositesa.2024.108267 用聚乳酸纳米纤维垫和定向聚乳酸带作夹层的自增强聚乳酸薄膜增韧研究Self-reinforced poly(lactic acid) composite (SRPLA) offers advantages in terms of convenient recycling due to its mono-material nature, potential biodegradability, and biocompatibility. Moreover, SRPLA has shown the ability to overcome the inherent brittleness of PLA. To deepen our understanding of how different types of reinforcements and process parameters can affect tensile properties, particularly tensile toughness, SRPLA has been prepared based on oriented tapes (ot-SRPLA) as well as nanofiber mats (nf-SRPLA) using a film-stacking and hot-compaction approach. A considerable improvement was observed in tensile strength, modulus, and toughness at the optimum consolidation temperature and time. Specifically, the tensile toughness of nf-SRPLA increased approximately threefold at a very low nanofiber loading of 0.56 wt%, while the toughness of ot-SRPLA more than doubled at a tape mass fraction of 36 wt%. In terms of toughening mechanisms, the presence of the nanofibers slowed down crack propagation through crack branching, deviation, and fiber bridging in nf-SRPLA, whereas the predominant toughening mechanisms were interlayer debonding and tape pull-out for ot-SRPLA.自增强聚乳酸复合材料(SRPLA)由于其单材料性质、潜在的生物降解性和生物相容性,在方便回收方面具有优势。此外,SRPLA还显示出克服PLA固有脆性的能力。为了加深我们对不同类型的增强剂和工艺参数如何影响拉伸性能,特别是拉伸韧性的理解,我们使用薄膜堆积和热压实方法制备了基于定向带(ot-SRPLA)和纳米纤维垫(nf-SRPLA)的SRPLA。在最佳固结温度和时间下,拉伸强度、模量和韧性均有显著提高。具体来说,在0.56 wt%的极低纳米纤维负载下,nf-SRPLA的拉伸韧性增加了约三倍,而在36 wt%的带质量分数下,t- srpla的韧性增加了一倍以上。在增韧机制方面,纳米纤维的存在通过裂缝分支、偏离和纤维桥接减缓了nf-SRPLA的裂纹扩展,而在t- srpla中,主要的增韧机制是层间脱粘和带拔出。Unraveling chemical and rheological mechanisms of self-healing with EMAA thermoplastics in fiber-reinforced epoxy compositesAlexander D. Snyder, Jack S. Turicek, Charles E. Diesendruck, Russell J. Varley, Jason F. Patrickdoi:10.1016/j.compositesa.2024.108271纤维增强环氧复合材料中EMAA热塑性塑料自愈的化学和流变机制研究Interlaminar delamination is a prevalent and insidious damage mode limiting the mechanical integrity and lifetime of fiber-reinforced composites. Conventional resolution involves over-design, laborious inspection, and repair/replacement at cost to the economy and environment. Self-healing via in situ thermal remending of thermoplastic interlayers offers a promising solution. However, better understanding of the healing agent and related mechanisms is necessary to tailor healing performance. Here, we compare non-neutralized (copolymer) and metallic-ion neutralized (ionomer) poly(ethylene-co-methacrylic acid) (EMAA) thermoplastics for healing interlaminar fracture. We reveal (i) how EMAA chemistry affects the interfacial reactions driving healing and (ii) the influence of molten viscosity on repair efficiency. At fixed viscosity, higher methacrylic acid content, chain mobility, and lower neutralization positively influence healing, where lower melt viscosity at fixed temperature improves delamination recovery. Thus, this study deepens scientific understanding of key variables for healing interlaminar fracture with EMAA, providing new insight for the design of multifunctional composites.层间分层是一种普遍存在的潜在损伤模式,限制了纤维增强复合材料的力学完整性和使用寿命。传统的解决方案涉及过度设计,费力的检查,以及以经济和环境为代价的维修/更换。通过热塑性夹层的原位热修复提供了一个很有前途的解决方案。然而,更好地了解愈合剂和相关机制对于调整愈合性能是必要的。在这里,我们比较了非中和(共聚物)和金属离子中和(离聚体)聚乙烯-共甲基丙烯酸(EMAA)热塑性塑料愈合板间骨折。我们揭示了(i) EMAA化学如何影响驱动愈合的界面反应和(ii)熔融粘度对修复效率的影响。在固定粘度下,较高的甲基丙烯酸含量、链迁移率和较低的中和作用对愈合有积极影响,其中固定温度下较低的熔体粘度有助于分层恢复。因此,本研究加深了对EMAA愈合椎间骨折关键变量的科学认识,为多功能复合材料的设计提供了新的见解。Assessing the impact of accelerated weathering on the mechanical properties of a flax/epoxy composite: A study on tensile performance and drop-weight impactAbdelhadi Hadj-Djilani, Habiba Bougherara, Redouane Zitoune, Lotfi Toubaldoi:10.1016/j.compositesa.2024.108277 评估加速风化对亚麻/环氧复合材料力学性能的影响:拉伸性能和落锤冲击的研究This study examined how UV exposure and humidity (accelerated weathering) affect flax/epoxy composites. Three configurations (unidirectional, cross-ply, and quasi-isotropic) were aged for 1200 h. Tensile and impact tests revealed significant property degradation in all configurations. Tensile strength, modulus, and strain all decreased after aging. Young’s modulus dropped by 8–11.5%, stress by 12.2–18%, and strain by 10–18.59%. Impact tests showed a decrease in tolerated impact load (6–10%) but an increase in absorbed energy (7–12%). This suggests more surface damage after aging. These results highlight the substantial influence of environmental factors on the long-term performance of flax/epoxy composites.本研究考察了紫外线暴露和湿度(加速风化)对亚麻/环氧复合材料的影响。三种结构(单向、交叉铺层和准各向同性)老化1200小时。拉伸和冲击试验显示,所有结构的性能都有明显的退化。时效后,拉伸强度、模量和应变均下降。杨氏模量下降8-11.5%,应力下降12.2-18%,应变下降10-18.59%。冲击试验表明,耐冲击载荷降低(6-10%),但吸收能量增加(7-12%)。这表明老化后表面损伤更大。这些结果凸显了环境因素对亚麻/环氧复合材料长期性能的实质性影响。Effect of alkaline treatment on hard vegetable shells on the properties of biobased abrasive wheelsNarcisse Defo, Omar Harzallah, Rodrigue Nicodème Tagne Sikame, Ebenezer Njeugna, Sophie Bistacdoi:10.1016/j.compositesa.2024.108278蔬菜硬壳碱性处理对生物基砂轮性能的影响One of challenges in composites research is to improve the quality of the interface fillers-matrix. The aim of this study was to evaluate the effect of sodium hydroxide (NaOH) treatment of coconut shells and palm kernel shells on the properties of wheels made. Shells were treated at concentrations of 1 %, 5 % and 10 % for 90 min before being used as abrasive grains to reinforce an epoxy matrix. The thermal degradation of shells was analyzed and the morphological study shows that the treatment modifies the surface of grains. The treatment led to a reduction in the water absorption rate of more than 10 % and the porosity of the grinding wheels of around 15 %. Statistical analysis showed that the treatment improved the material removal rate and wear resistance. The wheels treated with a concentration of 1 % gave better results with removal rates of 160 mg/s and wear rates of 3.86E-05 cm3/N.m.提高界面填料-基体的质量是复合材料研究面临的挑战之一。本研究的目的是评价氢氧化钠(NaOH)处理椰子壳和棕榈仁壳对车轮性能的影响。壳在1%、5%和10%的浓度下处理90分钟,然后用作磨粒增强环氧基。对壳的热降解进行了分析,形态学研究表明,处理改变了晶粒表面。处理后的砂轮吸水率降低10%以上,孔隙率降低15%左右。统计分析表明,该处理提高了材料去除率和耐磨性。以1%的浓度处理的车轮效果较好,去除率为160 mg/s,磨损率为3.86E-05 cm3/N.m。Mechanically robust, stretchable and environmentally adaptable organohydrogels with cross-linked fibrous structure for sensory artificial skinsKexuan Wang, Bohui Zheng, Ping Wu, Jialiang Lai, Hongli Zhang, Weifeng Zhao, Xilang Jin, Aijie Ma, Weixing Chen, Hanbin Liu, Hongwei Zhoudoi:10.1016/j.compositesa.2024.108274具有交联纤维结构的机械坚固,可拉伸和环境适应性强的有机水凝胶,用于感官人造皮肤Hydrogels are promising materials for fabricating sensory artificial skins (SASs), but their mechanical properties and environment adaptability are often limited, leading to restricted performances of SASs. In this work, mechanically robust, stretchable and environment adaptable organohydrogels with cross-linked fibrous structure are designed and constructed. The organohydrogels are prepared by introducing doped polyaniline (PANI) into cross-linked fibrous mats of poly(acrylic acid) (PAA) and poly(vinyl alcohol) (PVA). Cross-linked PAA-PVA mat works as skeleton to account for the mechanical robustness while PANI serves as the conductive component to achieve mechanosensing functionality. Due to the unique structure, the resultant organohydrogels, being denoted as PAA-PVA/PANI organohydrogels, exhibit high tensile strength (5.06MPa), stretchability, fatigue resistance and excellent environment adaptability (anti-freezing, anti-drying and swelling resistance). SASs of such organohydrogels have achieved a gauge factor of 1.81, a sensing range of 0–70 %, a response time of 0.28 s and a reversible sensing in more than 2,000 cycles. In addition, SASs are further attempted in monitoring diverse human motions and physiological activities, such as joint bending, muscle motion and pulse. Overall, this work has provided promising soft materials for future SASs that work properly under complicated environmental conditions.水凝胶是一种很有前途的感官人造皮肤材料,但其力学性能和环境适应性往往受到限制,导致其性能受到限制。在这项工作中,设计和构建了具有交联纤维结构的机械坚固,可拉伸和环境适应性强的有机水凝胶。将掺杂的聚苯胺(PANI)引入聚丙烯酸(PAA)和聚乙烯醇(PVA)交联纤维垫中制备有机水凝胶。交联PAA-PVA垫作为骨架,以说明机械稳健性,而聚苯胺作为导电组件,以实现机械传感功能。由于其独特的结构,所制得的有机水凝胶为PAA-PVA/PANI有机水凝胶,具有较高的抗拉强度(5.06MPa)、拉伸性、抗疲劳性和优异的环境适应性(抗冻、抗干燥、抗膨胀)。该有机水凝胶的SASs测量系数为1.81,传感范围为0-70 %,响应时间为0.28 s,可实现2000多次循环的可逆传感。此外,SASs还被进一步用于监测人体的各种运动和生理活动,如关节弯曲、肌肉运动和脉搏。总的来说,这项工作为未来在复杂环境条件下正常工作的SASs提供了有前途的软材料。Composites Science and TechnologySynergistic Enhancement of Strength and Toughness through Meta-Biomimetic Design: Integrating Crossed-Lamellar and Bouligand MicrostructuresXiaofang Zhang, Yanan Yuandoi:10.1016/j.compscitech.2024.110668 通过元仿生设计协同增强强度和韧性:整合交叉片层和Bouligand微观结构The development of fiber-reinforced polymer (FRP) composites, striking a balance between high strength and toughness, is a pressing requirement for the contemporary aerospace industry. Regarding the design of microstructures for enhancing strength and toughness, bionic crossed-lamellar and bouligand structures serve as noteworthy examples. However, individual biomimetic microstructures have approached the upper limit of their strengthening and toughening effects.This paper firstly proposed a “Meta-Biomimetic” design concept: hybridizing biological microstructures with defensive functionalities and those with offensive functionalities in mechanical design, aiming to achieve a metamaterial with both offensive and defensive capabilities. Namely this work retains the three-layer cross-lamellar microstructure of conch shells to stimulate subcritical damage for enhanced energy dissipation, while introducing a bouligand microstructure of lobster homarus americanus to increase the high load-bearing capacity at both tension and compression ends. The optimal design for enhancing the strength and toughness is the three-layer crossed-lamellar microstructure modified with a full bouligand structure, which increases strength and toughness simultaneously by more than 500% compared to natural structures. These studies are poised to not only steer the design of FRP microstructures towards enhanced strength and toughness but also furnish a foundation for interdisciplinary research in biomimetics within composite materials.在高强度和高韧性之间取得平衡的纤维增强聚合物(FRP)复合材料的发展是当代航空航天工业的迫切要求。在提高强度和韧性的微结构设计方面,仿生交叉片层结构和土石结构是值得注意的例子。然而,单个仿生微观结构已经接近其强化和增韧效果的上限。本文首先提出了“Meta-Biomimetic”设计概念:将具有防御功能的生物微结构与具有进攻功能的生物微结构在机械设计上进行杂交,以实现兼有进攻和防御能力的超材料。即,本研究保留了海螺壳的三层交叉片层微观结构,以刺 激亚临界损伤,增强能量耗散,同时引入美洲大龙虾的土石结构,以提高其拉压两端的高承载能力。提高强度和韧性的最佳设计是采用全土石结构改性的三层交叉片层微观结构,与天然结构相比,强度和韧性同时提高500%以上。这些研究不仅将引导FRP微结构的设计朝着增强强度和韧性的方向发展,而且还将为复合材料仿生学的跨学科研究奠定基础。High modulus carbon fiber based composite structural supercapacitors towards reducing internal resistance and improving multifunctional performanceGuocheng Qi, Jianxiong Wu, Bin Yao, Qian Cui, Liang Ren, Boming Zhang, Shanyi Dudoi:10.1016/j.compscitech.2024.110670 高模量碳纤维复合材料结构超级电容器,旨在降低内阻,提高多功能性能Carbon fibers (CFs) based composite structural supercapacitors (CSSs) are promising multifunctional energy storage composites which can simultaneously realize load bearing and electricity storage. The device power is still low due to the high internal resistance of CSS. Herein, the CFs, electrolytes, monofunctional devices and multifunctional composite devices were investigated to show the attribution of the internal resistances. Both the normally used T300 CF and high modulus M55J CF fabrics were utilized. The electric in-plane and through-the-thickness resistances of CF fabric electrodes were characterized, respectively. The internal resistance of the monofunctional supercapacitor devices which were assembled using liquid electrolyte were evaluated considering the effects of CF sizing. The bicontinuous structural electrolytes (BSEs) composed of epoxy (EP) and ionic liquid (IL) were prepared as the multifunctional matrix of the CSSs. The chemical structure, thermal stability and ionic conductivity of the BSEs were assessed. The activated carbon (AC) loaded CFs and BSEs were used to fabricate the CSSs. Both the tensile and charge/discharge properties of the M55J CF CSSs were higher than those of the T300 CF CSSs. This work could provide new insights into the resistance attribution of CSS and how to simultaneously improve both mechanical and electrochemical performances of CSSs.碳纤维复合结构超级电容器是一种很有前途的多功能储能复合材料,可同时实现承载和蓄电。由于CSS的内阻过高,导致设备功率仍然较低。本文研究了CFs、电解质、单功能器件和多功能复合器件的内阻属性。采用了常用的T300 CF和高模量M55J CF织物。对CF织物电极的面内电阻和透厚电阻进行了表征。考虑CF尺寸的影响,对液态电解液组装的单功能超级电容器器件的内阻进行了评价。制备了由环氧树脂(EP)和离子液体(IL)组成的双连续结构电解质(BSEs)作为多功能电解质的基体。评价了bse的化学结构、热稳定性和离子电导率。采用活性炭(AC)负载CFs和bse制备css。M55J CF CSSs的拉伸性能和充放电性能均高于T300 CF CSSs。该研究为进一步了解CSS的电阻属性以及如何同时提高CSS的力学和电化学性能提供了新的思路。来源:复合材料力学仿真Composites FEM

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