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【新文速递】2024年5月19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 6 篇

Journal of the Mechanics and Physics of Solids

Collaborative multiscale phase-field model for trans-scale fracture propagation of fiber-reinforced composites

Leying Song, Zhiming Xue, Zhenmeng Xia, Kunjie Wang, Chenghai Xu, Hui Qi

doi:10.1016/j.jmps.2024.105686

纤维增强复合材料跨尺度断裂扩展的协同多尺度相场模型

Owing to their inherent multiscale characteristics, cracks in fiber-reinforced composites initiate and propagate normally at the microscale level during loading, spanning spatial scales up to the macroscopic fracture failure of the material. Motivated by this phenomenon, this study proposes a collaborative multiscale phase-field (CMPF) approach to model the trans-scale fracture propagation of fiber-reinforced composites. The CMPF model includes a region-based phase-field model for characterizing matrix cracking, fiber breaking, and interface debonding at the microscale; a two-modes phase-field model for characterizing the axial and transverse fracture modes at the macroscale; and a bridging model for exchanging information (fracture modes, nonlinear stress–strain relationship, and strain levels) between the macro- and micro-models. Specifically, the real-time attenuation mechanical properties of the composite caused by crack propagation are first obtained at the microscopic scale and then transferred to the macroscopic two-modes phase-field model to map the trans-scale fracture propagation. The CMPF model is implemented within a finite-element package for numerical calculations and then applied to analyze the tensile-fracture behavior of needled carbon/carbon composites, which is a typical type of fiber-reinforced composite. The calculated results show that the transverse fracture mode nucleates successively within the needled region and then in a 90° nonwoven cloth layer, whereas the axial fracture mode arises within a 0° nonwoven cloth layer. The source of the transverse fracture is matrix cracking and that of the axial fracture is fiber breaking at the microscopic scale. In addition, the fracture properties and overlap of the needled region significantly affect the propagation paths of cracks, thus changing the strength and toughness of the composite. This CMPF model offers a promising approach for modeling and understanding the trans-scale fracture mechanisms of fiber-reinforced composites.

由于其固有的多尺度特性,纤维增强复合材料的裂纹在加载过程中在微观尺度上形成并正常扩展,跨越空间尺度直至材料的宏观断裂破坏。基于这一现象,本研究提出了一种协同多尺度相场(CMPF)方法来模拟纤维增强复合材料的跨尺度断裂扩展。CMPF模型包括一个基于区域的相场模型,用于表征微尺度下的基体开裂、纤维断裂和界面脱粘;在宏观尺度上描述轴向和横向断裂模式的双模相场模型以及一个桥接模型,用于在宏观和微观模型之间交换信息(断裂模式、非线性应力-应变关系和应变水平)。具体而言,首先在微观尺度上获得裂纹扩展引起的复合材料的实时衰减力学特性,然后将其转换为宏观双模相场模型,以映射跨尺度的断裂扩展。将CMPF模型应用于有限元程序包中进行数值计算,并应用于针 刺碳/碳复合材料的拉伸断裂行为分析,这是一种典型的纤维增强复合材料。计算结果表明,横向断裂模式先在针 刺区形成核,然后在90°无纺布层形成核,而轴向断裂模式在0°无纺布层形成核。在微观尺度上,横向断裂的来源是基体断裂,轴向断裂的来源是纤维断裂。此外,断裂特性和针尖区域的重叠显著影响裂纹的扩展路径,从而改变复合材料的强度和韧性。该CMPF模型为模拟和理解纤维增强复合材料的跨尺度断裂机制提供了一种很有前途的方法。


Mechanics of Materials

Molecular dynamic studies of the micromechanical response of titanium–aluminum layered twin structures and graphene

Tinghong Gao, Hong Huang, Jin Huang, Qian Chen, Qingquan Xiao

doi:10.1016/j.mechmat.2024.105050

钛铝层状孪晶结构与石墨烯微力学响应的分子动力学研究

The nanotwin structure and graphene (Gr)-reinforced phase can significantly enhance the mechanical properties of the material. However, there have been relatively few studies on the mechanisms underlying the strengthening resulting from the interaction between these two components in titanium–aluminum (TiAl) alloy materials. Here, molecular dynamics (MD) simulations were employed to investigate the mechanical properties and microstructural evolution of nanotwinned TiAl/Gr (nt-TiAl/Gr) composites under uniaxial loading. The study investigated the influence of Gr layer number and temperature on composite properties. Results demonstrate that the twin boundary structure interacts with graphene, enhancing mechanical properties synergistically. Relative to pure nt-TiAl, the maximum tensile strength increased by 7.42%, 24.66%, and 35.86% for varying Gr layers. Furthermore, the mechanical properties of nt-TiAl/Gr composites exhibit an inverse correlation with temperature, where maximum tensile strength decreases with temperature elevation. The synergy between Gr and the twin structure significantly inhibits dislocation diffusion and diminishes dislocation nucleation, thus improving the properties of the composite.

纳米孪晶结构和石墨烯(Gr)增强相可以显著提高材料的力学性能。然而,关于这两种成分在钛铝(TiAl)合金材料中相互作用的强化机制的研究相对较少。本文采用分子动力学(MD)模拟研究了纳米孪晶TiAl/Gr (nt-TiAl/Gr)复合材料在单轴载荷作用下的力学性能和微观组织演变。研究了Gr层数和温度对复合材料性能的影响。结果表明,双晶界结构与石墨烯相互作用,协同提高了材料的力学性能。相对于纯nt-TiAl,不同Gr层的最大抗拉强度分别提高了7.42%、24.66%和35.86%。此外,nt-TiAl/Gr复合材料的力学性能与温度呈反比关系,最大抗拉强度随温度升高而降低。Gr与孪晶组织的协同作用显著抑制位错扩散,减少位错成核,从而改善复合材料的性能。


Thin-Walled Structures

Compressive failure analysis of composite honeycomb sandwich panels with impact damage and stepped-scarf repairs

Wen Xiao, Ganggang Sha, Xiaohua Lu, Hongfu Zuo, Maosen Cao, Wiesław Ostachowicz

doi:10.1016/j.tws.2024.112012

复合材料蜂窝夹芯板冲击损伤及分步修复的压缩破坏分析

Composite honeycomb sandwich panels (CHSPs) have been widely used in the aerospace industry owing to their lightweight and superior mechanical properties. However, these CHSPs are susceptible to impact damage, leading to a significant reduction in compressive strength and potentially jeopardize aircraft safety. It is crucial to investigate repair methods for CHSPs with impact damage. This paper aims to evaluate the repair performance of CHSPs with impact damage through an analysis of their compressive failure behaviors. To accomplish this, both experimental tests and advanced numerical models are employed. The numerical models for the intact, damaged and stepped-scarf repaired CHSPs are established using the progressive failure analysis model, cohesive zone model and sandwich plate theory. A good agreement is observed between the experimental results and numerical predictions of compressive failure behaviors. Moreover, the validated numerical models are successfully utilized for determining optimum repair parameters by parametric analysis of the repaired CHSPs. The establishment of these numerical models offers an accurate and cost-effective evaluation of repair performance for CHSPs with impact damage, highlighting the novelty and main contribution of this paper.

复合材料蜂窝夹芯板(CHSPs)由于其轻量化和优异的力学性能在航空航天工业中得到了广泛的应用。然而,这些chsp容易受到冲击损坏,导致抗压强度显著降低,并可能危及飞机安全。研究具有冲击损伤的热电堆的修复方法至关重要。本文旨在通过分析chsp的压缩破坏行为来评估其修复性能。为了实现这一目标,采用了实验测试和先进的数值模型。采用递进破坏分析模型、内聚区模型和夹层板理论建立了完整、破损和阶梯式修复的热电机组数值模型。实验结果与数值模拟结果吻合较好。此外,通过对修复后的chsp进行参数分析,成功地将验证的数值模型用于确定最佳修复参数。这些数值模型的建立为具有冲击损伤的热电机组的修复性能提供了准确和经济的评估,突出了本文的新颖性和主要贡献。


Mechanical and dynamic performance of 3D-printed continuous carbon fibre Onyx composites

Vuong Nguyen-Van, Chenxi Peng, Phuong Tran, Sachini Wickramasinghe, Truong Do, Dong Ruan

doi:10.1016/j.tws.2024.111979

3d打印连续碳纤维玛瑙复合材料的力学和动态性能

The increasing attention towards 3D-printed fibre-reinforced thermoplastic composite structures is due to their superior characteristics, ability to produce intricate architectures, repeatability, and short lead times. This experimental study aims to investigate the mechanical and dynamic behaviours of 3D-printed composite structures under tensile and impact tests. Different types of specimens are designed, including Onyx layers, triangular infill patterns (30% and 40% infill density), and continuous carbon fibre layers (two, four, six, and eight layers). Scanning electron microscopy (SEM) and X-ray micro-computed tomography (μCT) analyses are conducted to visualise the morphological characterisation and observe the delamination and damage of the composite structures. The results of the study reveal that the inclusion of carbon fibre reinforcement layers increases the stiffness and tensile strength of the composite structures. Furthermore, the addition of fibre layers in the composite panels provides critical support in damage resistance against impact loading. In contrast, sandwich structures without reinforcement layers are fatally punctured by the impact force, resulting in significant damage on both the impacted and bottom surfaces. The composite sandwich panels with fewer fibre-reinforced layers and lower infill density become softer and absorb impact energy better.

人们越来越关注3d打印纤维增强热塑性复合材料结构,因为它们具有优越的特性,能够生产复杂的结构,可重复性和短的交货时间。本实验研究旨在研究3d打印复合材料结构在拉伸和冲击试验下的力学和动态行为。设计了不同类型的试样,包括玛瑙层、三角形填充图案(30%和40%填充密度)和连续碳纤维层(两层、四层、六层和八层)。利用扫描电子显微镜(SEM)和x射线显微计算机断层扫描(μCT)分析了复合材料的形态特征,并观察了复合材料结构的分层和损伤情况。研究结果表明,碳纤维增强层的加入提高了复合材料结构的刚度和抗拉强度。此外,复合材料板中添加的纤维层提供了抗冲击载荷损伤的关键支撑。相比之下,没有加固层的夹层结构则会被冲击力刺穿,造成撞击面和底面的严重损伤。纤维增强层数较少、填充密度较低的复合材料夹层板具有较好的柔软性和抗冲击性能。


Experimental investigation into demountable dry connections for fully precast frame structures through shaking table tests

Ruijun Zhang, Tong Guo, Aiqun Li

doi:10.1016/j.tws.2024.112014

全预制框架结构可拆卸干连接振动台试验研究

To fulfill the objective of reducing pollution and carbon emission while advancing the development of high-performance structural systems aligned with green building principles, an innovative demountable dry connection fully precast frame structure system was introduced in this paper. The structure is easy to assemble, can significantly enhance construction efficiency, and facilitates the upgrading and earthquake-damaged replacement of components during service. To comprehensively investigate the dynamic characteristics of this novel precast frame structure, a half-scale specimen structure was manufactured and tested on a shaking table. The seismic performance of the structure was evaluated by collecting and analyzing the data on acceleration, displacement, and strain, as well as observing the deformation and cracking of the structure. The results show that the structure performs well as designed with confined damage, and can achieve the performance target of withstanding minor earthquakes without damage and surviving severe earthquakes without collapsing. After experiencing strong earthquakes, the damage was concentrated on the concrete beams, and the damaged components were easy to demount and replace, which could extend the service life of the structure, ensure the sustainability of the structural seismic resistance, and present an effective solution for achieving environmentally conscious, green, and low-carbon construction practices.

为了实现减少污染和碳排放的目标,同时推进符合绿色建筑原则的高性能结构体系的发展,本文介绍了一种创新的可拆卸干连接全预制框架结构体系。该结构易于组装,可显著提高施工效率,便于在使用过程中对部件进行升级和地震损坏更换。为了全面研究这种新型预制框架结构的动力特性,制作了半比例尺结构试件并在振动台上进行了试验。通过收集和分析结构的加速度、位移和应变数据,以及观察结构的变形和开裂,对结构的抗震性能进行了评价。结果表明,该结构性能符合设计要求,损伤有限,能达到小震不破坏、大震不倒塌的性能目标。经历强震后,破坏集中在混凝土梁上,损坏构件易于拆卸和更换,可以延长结构的使用寿命,保证结构抗震的可持续性,为实现环保、绿色、低碳的建筑实践提供了有效的解决方案。


Elastic Properties Prediction of Two- and Three-Dimensional Multi-Material Lattices

Parham Mostofizadeh, Robert A. Dorey, Iman Mohagheghian

doi:10.1016/j.tws.2024.112015

二维和三维多材料晶格的弹性特性预测

Advances in multi-material additive manufacturing have opened unprecedented new opportunities for the design and manufacture of lightweight multifunctional structures. The ability to create complex topologies, at a relatively fine resolution, in addition to controlling the material composition on a voxel basis have significantly expanded the design space. To explore this large design space efficiently, accurate and cost-effective modeling tools are essential. In this paper, mechanics-based models for predicting the elastic properties of multi-material 2D and 3D lattice structures are developed or extended. The outcomes are compared with the predictions obtained from finite element models and experimental data. The results reveal that the adapted analytical models demonstrate good accuracy in predicting the elastic modulus of multi-material lattices for relative densities up to approximately 25% while have considerably less computational cost compared to finite element using solid elements (providing the most accurate results in comparison with experiment). Careful consideration of the accuracy of the predictions is necessary for the use of these models for lattices with high relative density values. Besides, several homogenization-based models were studied to investigate their applicability to multi-material lattice structures when the assumption of scale-separation is considered valid. The capability of these models in predicting the whole elasticity tensor and the potential of multi-material lattices in manipulating the anisotropy are demonstrated. Finally, the introduced prediction frameworks are compared in order to provide an overview of their respective advantages and disadvantages in the case of multi-material lattice structures.

多材料增材制造技术的进步为轻量化多功能结构的设计和制造提供了前所未有的新机遇。除了在体素基础上控制材料组成外,以相对精细的分辨率创建复杂拓扑的能力大大扩展了设计空间。为了有效地探索这个巨大的设计空间,准确和经济有效的建模工具是必不可少的。本文发展或扩展了基于力学的多材料二维和三维晶格结构弹性特性预测模型。结果与有限元模型和实验数据的预测结果进行了比较。结果表明,适应的分析模型在预测相对密度高达约25%的多材料晶格弹性模量方面表现出良好的准确性,而与使用实体单元的有限元相比,计算成本大大降低(与实验相比,提供了最准确的结果)。对具有高相对密度值的晶格使用这些模型时,必须仔细考虑预测的准确性。此外,还研究了几种基于均质化的模型,以考察其在尺度分离假设成立的情况下对多材料晶格结构的适用性。证明了这些模型在预测整个弹性张量方面的能力以及多材料晶格在控制各向异性方面的潜力。最后,对引入的预测框架进行了比较,以概述其在多材料晶格结构情况下的优缺点。


Elastic wave demultiplexer with frequency dependent topological valley Hall edge states

Zheng Wu, Jiyue Chen, Weihan Wang, Jie Xu, Shixuan Shao, Rongyu Xia, Zheng Li

doi:10.1016/j.tws.2024.111997

具有频率相关拓扑谷霍尔边缘态的弹性波解复用器

Valley Hall topological insulators (VHTIs) hold great promise for enhancing the manipulation of elastic wave propagation by their intrinsic topologically protected mechanism. Different from most of VHTIs designed by the deterministic Dirac degeneracy, a more flexible design of VHTIs is proposed by the accidental Dirac degeneracy to steer elastic wave propagation. Based on the accidental Dirac degeneracy, a kind of hexagonal phononic crystal is designed to independently control the topological phase transitions at different frequency ranges. Consequently, a two-channel topological demultiplexer is designed with the function of frequency separation for flexural waves, and its effectivity is verified by numerical simulations and experimental testing. Comparing with traditional designs of demultiplexers, the VHTIs-based demultiplexer possesses a series of advantages in robust performance, easy fabrication and low energy leakage, and sheds light on developing new generation of elastic wave devices.

谷霍尔拓扑绝缘子(VHTIs)凭借其固有的拓扑保护机制,在增强弹性波传播的操纵方面具有很大的前景。与大多数采用确定性狄拉克简并设计的vhti不同,本文采用偶发狄拉克简并设计了一种更灵活的vhti,以引导弹性波的传播。基于偶然狄拉克简并,设计了一种能独立控制不同频率范围拓扑相变的六方声子晶体。为此,设计了一种具有弯曲波分频功能的双通道拓扑解复用器,并通过数值模拟和实验测试验证了其有效性。与传统的解复用器设计相比,基于vhtis的解复用器具有性能稳定、制作简单、能量泄漏小等优点,为开发新一代弹性波器件提供了思路。


Review on the protective technologies of bridge against vessel collision

Wen Zhe Zhang, Jin Pan, Javier Calderon Sanchez, Xiao Bin Li, Ming Cai Xu

doi:10.1016/j.tws.2024.112013

桥梁船舶碰撞防护技术综述

The collisions between bridges and ships might cause severe damage to both of them, which is impossible to avoid completely, although several specifications or requirements need to be followed in the design of bridges and during the navigation of ships passing bridge. Many researches on protective technology had been conducted to reduce the potentially disastrous consequences. These technologies can be broadly categorized into two main types: the technologies of collision avoidance, which try to reduce the collision possibility by warning the passing ship that might impact the bridge; and passive collision protections, which use protective structures to minimize the damage of bridge and ship due to impact. The purpose of the present paper is to systematically summarize both classifications and then provide insights into their characteristics, advantages, disadvantages, and suitable conditions for application. Additionally, the related approaches originally designed for other applications but with potential relevance are also discussed, such as ship-ship collision avoidance. This review can serve as meaningful guidance and reference for future research and realistic engineering applications.

桥梁与船舶的碰撞可能会对双方造成严重的损害,这是不可能完全避免的,尽管在桥梁设计和船舶过桥航行中需要遵循一些规范或要求。为了减少潜在的灾难性后果,人们进行了许多保护技术的研究。这些技术大致可分为两大类:避碰技术,即通过警告过往船只可能撞击桥梁来降低碰撞的可能性;被动碰撞防护,利用防护结构将桥梁和船舶因撞击造成的损害降到最低。本文的目的是系统地总结这两种分类,然后对它们的特点、优点、缺点和适用条件提供见解。此外,还讨论了最初为其他应用而设计但具有潜在相关性的相关方法,例如船-船避碰。对今后的研究和实际工程应用具有一定的指导和借鉴意义。




来源:复合材料力学仿真Composites FEM
ACTMechanicalAdditiveSystemDeform振动断裂复合材料碰撞非线性航空航天船舶建筑电子裂纹理论电机材料分子动力学
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【新文速递】2024年4月27日固体力学SCI期刊最新文章

今日更新:International Journal of Solids and Structures 1 篇,Journal of the Mechanics and Physics of Solids 3 篇,International Journal of Plasticity 2 篇,Thin-Walled Structures 5 篇International Journal of Solids and StructuresBuckling optimization of variable-stiffness composite plates with two circular holes using discrete Ritz method and potential flowZhao Jing, Lei Duan, Siqi Wangdoi:10.1016/j.ijsolstr.2024.112845基于离散Ritz法和势流的双孔变刚度复合材料板屈曲优化Potential flow around two equal-radius cylinders is derived analytically and applied to generate the curvilinear fiber path of variable-stiffness composite (VSC) plates with two circular holes. As complex variable theory and conformal mapping are used to generate the potential flow around two equal-radius cylinders, the location and size of the two equal-radius circular holes are arbitrary. By changing the angle of incoming flow, the global fiber angle of a variable-stiffness lamina can be simulated and the local fiber orientation angle at any point is determined by the global potential flow field. Buckling performance of variously-shaped VSC plates with two circular holes are investigated via a novel numerical method − discrete Ritz method (DRM). DRM combines the extended interval integral, Gauss quadrature, and variable stiffness within a rectangular domain and builds a discrete energy system to simulate the plate, which allows the geometric boundaries of the plate to vary. The strain energy of a plate is modeled in the rectangular domain, discretized using Gauss points, and is characterized by variable stiffness, which characterizes both the material distribution and plate geometry simultaneously. After that, a three-dimensional sampling optimization (3DSO) method is adopted to optimize the curvilinear fiber configurations of VSC plates, and its buckling performances are compared with those of constant stiffness composites (CSC) with straight fibers. Significant improvements on load-carrying capacity can be achieved compared to straight ones, demonstrating that using potential flow is one of the most efficient way to generate curvilinear optimal fiber path with maximum load-carrying capacity for VSC plates with material discontinuity. Moreover, DRM exhibits good precision and stability for buckling analysis of VSC plates with complex geometries分析了两等半径圆柱体周围的势流,并将其应用于两圆孔变刚度复合材料板的曲线纤维路径的生成。由于采用复变理论和保角映射生成两个等半径圆柱体周围的势流,两个等半径圆孔的位置和大小是任意的。通过改变入射气流的角度,可以模拟变刚度板的整体纤维角,并由整体势流场确定任意点的局部纤维取向角。采用一种新的数值方法——离散里兹法(DRM)研究了带两个圆孔的不同形状VSC板的屈曲性能。DRM结合了扩展区间积分、高斯正交和矩形域内变刚度,建立了一个离散能量系统来模拟板,允许板的几何边界变化。板的应变能在矩形域中建模,采用高斯点离散,并具有变刚度的特征,同时表征了材料分布和板的几何形状。然后,采用三维采样优化(3DSO)方法对VSC板的曲线纤维结构进行优化,并将其屈曲性能与直纤维恒刚度复合材料(CSC)的屈曲性能进行比较。与直线路径相比,该路径的承载能力得到了显著提高,这表明对于材料不连续的VSC板,利用势流是生成承载能力最大的曲线最优光纤路径的最有效方法之一。此外,对于具有复杂几何形状的VSC板的屈曲分析,DRM具有良好的精度和稳定性Journal of the Mechanics and Physics of SolidsContact stiffness of the multi-indenter contact interfaceYongbin Wang, Jinsheng Zhao, Yuxiang He, Mingshan Yang, Jielei Chu, Jianghong Yuan, Xiangyu Li, Weiqiu Chendoi:10.1016/j.jmps.2024.105659多压头接触界面的接触刚度Mechanical contact plays a pivotal role in both industrial and daily life applications. Contact stiffness of a multi-indenter contact interface fundamentally determines force–deformation relations. However, the understanding of the overall contact stiffness from the historical perspective is limited owing to inherent difficulties in precisely characterizing the interaction in multi-indenter contacts. In this study, the mechanical strong interaction among indenters is pinpointed. A theoretical model for accurately determining the contact stiffness of multi-indenter contact interface is developed. The physical mechanism of the contact stiffness of multi-indenter contact interface is revealed. The theoretical model is solidly validated by experiment and simulation. More importantly, the present theoretical model can predict the contact stiffness of contact interfaces with complex and irregular configurations, which may be filled up with indenters of hierarchical structures. The critical load is determined to guarantee the finished product rate during transfer printing. This is experimentally evidenced by the transfer printing of silicon wafer with complexly customized patterns. The present study provides a profound guidance for various engineering applications such as fabrication and integration of micro- and nano-electronic chips as well as electronic devices.机械接触在工业和日常生活中都起着举足轻重的作用。多压头接触界面的接触刚度从根本上决定了力-变形关系。然而,从历史角度理解整体接触刚度是有限的,因为在精确表征多压头接触中的相互作用方面存在固有的困难。在这项研究中,确定了压头之间的机械强相互作用。建立了精确确定多压头接触界面接触刚度的理论模型。揭示了多压头接触界面接触刚度的物理机理。通过实验和仿真验证了理论模型的正确性。更重要的是,该理论模型可以预测具有复杂和不规则结构的接触界面的接触刚度,这些界面可能充满分层结构的压痕。为保证转移印花的成品率,确定了临界负荷。通过实验证明了这一点,并对具有复杂定制图案的硅片进行了转移印刷。本研究对微纳电子芯片及电子器件的制造与集成等多种工程应用具有深远的指导意义。Incompatibility-driven growth and size control during developmentA. Erlich, G. Zurlodoi:10.1016/j.jmps.2024.105660开发过程中不兼容性驱动的增长和规模控制Size regulation in living organisms is a major unsolved problem in developmental biology. This is due to the intrinsic complexity of biological growth, which simultaneously involves genetic, biochemical, and mechanical factors. In this article, we propose a novel theoretical framework that explores the role of incompatibility, the geometric source of residual stress in a growing body, as a possible regulator of size termination during development. We explore this paradigm both at the level of a model 2D cell, and at the level of continuous tissues. After establishing a parallel between incompatibility and the shape parameter of vertex models, we show that incompatibility-driven growth leads to size control in a model 2D cell. We then extend the same paradigm to the level of continuous bodies, where incompatibility is measured by the Ricci curvature of the growth tensor. By using the model 2D cell as a template, we now derive an evolutionary law for the growth tensor with curvature fixed at a physiological value. When the analysis is specialised to radial symmetry (discs and spheres), this model captures the salient features observed in Drosophila wing discs and multicellular spheroids: these systems have a target size and build up residual stresses that cause the tissue to open in response to a radial cut, with the cut edges curling outward. The theory proposed in this work suggests that incompatibility in a growing biological tissue is potentially controllable at the cell level, and that incompatibility-driven growth provides an effective method of controlling global information (stress, size) through local geometric controls.生物的大小调节是发育生物学中尚未解决的主要问题。这是由于生物生长的内在复杂性,它同时涉及遗传、生化和机械因素。在本文中,我们提出了一个新的理论框架,探讨了不相容的作用,在一个生长体的几何来源的残余应力,作为一个可能的调节尺寸终止在发展过程中。我们在模型二维细胞水平和连续组织水平上探索这种范式。在建立顶点模型的不兼容性和形状参数之间的平行关系后,我们表明不兼容性驱动的增长导致模型二维单元的大小控制。然后,我们将相同的范例扩展到连续体的水平,其中不相容是通过生长张量的里奇曲率来测量的。通过使用模型二维细胞作为模板,我们推导出曲率固定在生理值的生长张量的进化规律。当分析专门针对径向对称(圆盘和球体)时,该模型捕捉到了在果蝇翅盘和多细胞球体中观察到的显著特征:这些系统有一个目标尺寸,并建立残余应力,导致组织在径向切割时打开,切割边缘向外卷曲。这项工作提出的理论表明,生长中的生物组织中的不相容性在细胞水平上是潜在的可控的,并且不相容性驱动的生长提供了一种通过局部几何控制来控制全局信息(应力,大小)的有效方法。Mechanics of Abrasion-Induced Particulate Matter EmissionKetian Li, Yanchu Zhang, Kunhao Yu, Haixu Du, Constantinos Sioutas, Qiming Wangdoi:10.1016/j.jmps.2024.105661磨损诱发颗粒物排放的力学研究Microplastic pollution constitutes a substantially detrimental type of environmental contamination and poses threats to human health. Among the sources of airborne and marine microplastics, evidence indicates that non-exhaust emissions resulting from tire abrasion and other organic materials have emerged as a notable contributor. However, the mechanistic understanding of abrasion emission of organic materials has remained elusive. To fill the gap, we here develop a multi-scale abrasion mechanics model using the principles of linear elastic fracture mechanics. Macroscopically, material wear and tear can be viewed as a process of macro-crack propagation associated with the fatigue fracture. Microscopically, we consider the effect of microcracks propagating under cyclic loading on the material modulus and energy release rate during fatigue fracture. This framework leads to an evaluation of the effective energy release rate for the abrasion-induced emission of particulate matter, thus leading to a calculation of the concentration of the emitted particulate matter with varied sizes. The theory is validated by corresponding experiments and high consistency is exhibited between the theoretical and experimental results. This research constructs a quantitative relationship between fracture mechanics and abrasion emissions. This research not only paves the way for a mechanistic understanding of particulate matter pollution from a solid mechanics perspective but also offers rational guidance for modern society to alleviate airborne particulate matter and marine microplastic abrasion emissions.微塑料污染是一种极为有害的环境污染,对人类健康构成威胁。在空气和海洋微塑料的来源中,有证据表明,轮胎磨损和其他有机材料产生的非废气排放已成为一个显着的贡献者。然而,有机材料的磨损发射机理的理解仍然是难以捉摸的。为了填补这一空白,我们利用线弹性断裂力学原理建立了一个多尺度磨损力学模型。从宏观上看,材料的磨损可以看作是伴随疲劳断裂的宏观裂纹扩展过程。微观上考虑了循环载荷下微裂纹的扩展对疲劳断裂过程中材料模量和能量释放率的影响。该框架可用于评估磨损引起的颗粒物排放的有效能量释放率,从而计算不同大小的排放颗粒物的浓度。通过相应的实验对理论进行了验证,理论结果与实验结果具有较高的一致性。本研究建立了断裂力学与磨损排放之间的定量关系。本研究不仅为从固体力学角度对颗粒物污染的机理认识铺平了道路,而且为现代社会减轻大气颗粒物和海洋微塑料磨损排放提供了合理的指导。International Journal of PlasticityUnderstanding the strain localization in additively manufactured materials: Micro-scale tensile tests and crystal plasticity modelingDaijun Hu, Zixu Guo, Nicolò Grilli, Aloysius Tay, Zhen Lu, Wentao Yandoi:10.1016/j.ijplas.2024.103981 了解增材制造材料中的应变局部化:微尺度拉伸试验和晶体塑性建模Metallic parts fabricated by additive manufacturing (AM) usually exhibit unique microstructures and non-negligible residual stresses compared with the counterparts produced by conventional manufacturing. These inherent microstructural factors strongly affect the mechanical response of the as-built AM parts. In this study, we focus on the strain localization behavior of 316L stainless steel produced by laser powder-bed-fusion. In-situ tensile tests under a scanning electron microscope are performed, and the digital image correlation method is used to measure the strain distribution combined with electron backscatter diffraction. Meanwhile, a dislocation-based crystal plasticity finite element model incorporating residual stresses is developed to study the origins of the strain localization in the AM material. The results indicate that strain localization in AM materials is closely associated with microstructural features, encompassing behaviors related to slip activities, interactions with neighboring grains and dislocation evolutions. Additionally, the columnar grain features also render the strain distribution sensitive to the loading direction. The strain localization is serious in some small grains with high residual stresses, while in large grains the effect is less significant. These factors collectively contribute to the increasing likelihood of strain localization occurring in the AM microstructures with heterogeneous grain size and texture distribution. This work provides detailed insights into the strain localization in AM materials and would facilitate the manufacturing parameter optimization of AM materials by tuning the microstructure to reduce deformation inhomogeneity.与传统制造的金属零件相比,增材制造制造的金属零件通常具有独特的微观结构和不可忽略的残余应力。这些固有的微观结构因素强烈地影响着成品增材制造零件的力学响应。在本研究中,我们重点研究了激光粉末床熔合生产的316L不锈钢的应变局部化行为。在扫描电镜下进行了原位拉伸试验,并采用数字图像相关法结合电子背散射衍射测量了应变分布。同时,建立了包含残余应力的位错晶体塑性有限元模型,研究了增材制造材料应变局部化的根源。结果表明,AM材料中的应变局部化与微观结构特征密切相关,包括与滑移活动、与邻近晶粒的相互作用和位错演化相关的行为。此外,柱状晶粒特征也使得应变分布对加载方向敏感。在残余应力较大的小晶粒中,应变局部化现象较为严重,而在大晶粒中则不太明显。这些因素共同导致了具有非均匀晶粒尺寸和织构分布的AM微结构中应变局部化的可能性增加。这项工作为增材制造材料的应变局部化提供了详细的见解,并将通过调整微观结构来减少变形不均匀性,从而促进增材制造材料的制造参数优化。Study of the mechanism of the strength-ductility synergy of α-Ti at cryogenic temperature via experiment and atomistic simulationHeng Yang, Heng Li, Hong Sun, Haipeng Wang, M.W. Fudoi:10.1016/j.ijplas.2024.103971通过实验和原子模拟研究α-Ti在低温下强度-延性协同作用的机理Alpha titanium (α-Ti) is a promising material for making high-performance components for applications in aerospace, marine, energy and healthcare fields. The excellent strength-ductility synergy has been observed for α-Ti at cryogenic temperature. Twinning is generally considered a key mechanism of outstanding cryogenic ductility. The dislocation-grain boundaries (GBs) interaction and void nucleation usually play crucial roles in the plastic deformation of polycrystalline materials, but their effects on the cryogenic ductility of α-Ti are rarely considered. To eliminate this confusion and gain an in-depth insight into the mechanism of the cryogenic strength-ductility synergy of α-Ti, in this work, a series of characterization experiments and molecular dynamics (MD) simulations were designed and carried out. 1) From uniaxial tension tests of the coarse-grained α-Ti sheets at the temperature from 25 to -180°C, the uniform elongation and post-necking elongation were increased by 92% and 20%, respectively. The material maintained a larger strain hardening rate within a greater range of strain at cryogenic temperature compared with room temperature. 2) Via microstructure and fractography observations and the analysis of slip and geometrically necessary dislocation (GND) activities, the uniform plastic deformation was mainly accomplished by prismatic slip, whether at room temperature or at cryogenic temperature. The significantly increased uniform elongation is mainly attributed to the more uniform distribution of GND pile-ups at cryogenic temperature. 3) The MD simulations revealed that cryogenic temperatures made the GBs present a stronger barrier effect on dislocation transmission compared with that at room temperature, contributing to the more uniform distribution of GNDs and lower densities of GND pile-ups. The GBs at cryogenic temperature show a greater ability to resist void nucleation due to the decreased accumulation rate of excess potential energy and increased energy required to void nucleation. The larger strains were thus required to increase the densities of GND pile-ups to induce large stress concentrations for driving void nucleation. This made the uniform elongation of α-Ti increase significantly at cryogenic temperature. This study revealed that the enhanced barrier effect of GBs on dislocation transmission and the improved ability of GBs to resist void nucleation are key mechanisms besides twinning governing the cryogenic strength-ductility synergy of α-Ti. The understanding developed in this work can be useful for the development of new high-performance materials and the precise forming of complex components with high quality.α钛(α-Ti)是一种很有前途的材料,可用于制造应用于航空航天、海洋、能源和医疗保健领域的高性能部件。α-Ti在低温下表现出优异的强度-塑性协同效应。孪生通常被认为是突出的低温延展性的关键机制。位错-晶界相互作用和空穴成核在多晶材料的塑性变形中起着至关重要的作用,但它们对α-Ti低温塑性的影响却很少被考虑。为了消除这种混淆,深入了解α-Ti低温强度-延性协同作用的机制,本研究设计并开展了一系列表征实验和分子动力学(MD)模拟。1)粗晶α-Ti片材在25 ~ -180℃的单轴拉伸试验中,均匀伸长率和后颈伸长率分别提高了92%和20%。与室温相比,材料在低温下在更大的应变范围内保持了更大的应变硬化速率。2)通过显微组织和断口形貌观察以及滑移和几何必要位错(GND)活动分析,无论在室温还是低温下,均匀塑性变形主要由棱柱滑移完成。均匀伸长率的显著提高主要是由于低温下GND堆积分布更加均匀。3) MD模拟结果表明,与室温相比,低温使gds对位错传递具有更强的阻挡作用,使得gds分布更均匀,堆积密度更低。低温下的GBs由于多余势能积累速率的降低和空穴成核所需能量的增加而表现出更强的抗空穴成核能力。因此,需要较大的应变来增加GND堆积的密度,以诱导大的应力集中以驱动空洞成核。这使得α-Ti在低温下的均匀伸长率显著提高。研究表明,除了孪晶外,GBs对位错传递的阻挡作用增强和抗空洞成核能力的提高是控制α-Ti低温强度-塑性协同作用的关键机制。在这项工作中发展起来的理解对于开发新的高性能材料和高质量复杂部件的精确成形是有用的。Thin-Walled StructuresGlobal interactive-mode imperfection generation for K6 single-layer latticed shell using generative adversarial networksKaidong Wu, Yecheng Zhang, Bingbing San, Zhe Xingdoi:10.1016/j.tws.2024.111932基于生成对抗网络的K6单层格壳全局交互模式缺陷生成The worst imperfection shape of K6 single-layer latticed shells corresponding to the lowest nonlinear load-carrying capacity is difficult to be obtained in design owing to significant multi-modal interaction. The global interactive buckling of the K6 single-layer latticed shell is investigated numerically, and the intelligent model for generating its worst global interactive-mode imperfection is developed via generative adversarial networks (GAN). For the cases vulnerable to interactive buckling, the load-carrying capacity is found to be reduced significantly up to 35% with two-mode interaction considered, and unstable behaviour, such as the dominant mode changing due to the deformation evolution of different modal components, is observed at the post-buckling stage. Moreover, the GAN model for generating the worst imperfection shape and the artificial neural network for evaluating the corresponding ultimate load are developed based on the data obtained from numerical analysis. The time of training model to converge is less than 30 min, and the generating process using the trained model only takes a few seconds. It is demonstrated that for the K6 single-layer latticed shells, the developed models can give the worst imperfection and the corresponding ultimate load accurately and efficiently with interactive buckling considered well. This work can be used to develop the programming module for the intelligent design of latticed shells in future.由于存在明显的多模态相互作用,在设计中很难得到K6单层网壳非线性承载能力最低的最大缺陷形状。对K6单层网壳的全局交互屈曲进行了数值研究,并利用生成对抗网络(GAN)建立了生成其最坏全局交互模态缺陷的智能模型。对于易受交互屈曲影响的情况,考虑双模态相互作用的情况下,承载能力显著降低35%,并且在屈曲后阶段观察到不稳定行为,例如由于不同模态分量的变形演变而导致的主导模态变化。基于数值分析数据,建立了最坏缺陷形状生成的GAN模型和相应极限荷载的人工神经网络。训练模型收敛时间小于30 min,使用训练模型生成过程仅需几秒。结果表明,对于K6单层网壳,所建立的模型在充分考虑相互屈曲的情况下,能准确有效地给出最大缺陷和相应的极限载荷。本文的工作可为今后格壳智能化设计的编程模块的开发提供参考。Nonlinear Thermoelastic Wave Propagation in General FGM Sandwich Rectangular PlatesChen Liang, Guifeng Wang, Zhenyu Chen, C.W. Limdoi:10.1016/j.tws.2024.111933 非线性热弹性波在一般FGM夹层矩形板中的传播The present work is dedicated to investigating the thermoelastic wave propagation behavior of sandwich rectangular plates (SRP) made of functionally graded material (FGM). The main contribution lies in the partial modification of basic theoretical expressions and solution methods to improve the accuracy of practical system models. An analytical model with three types of general configurations is established. The porosity distribution in FGM layers depends on the degree of mixture of the constituent materials, with the FGM layers without porosity taken as a reference model. The effect of porosity within FGMs is addressed through a refined analytical formulation of material properties, and the temperature-dependent material properties of FGM sandwich structures (FGMSS) maintain continuity through the thickness. This improved framework introduces a porosity function encompassing three distinct structural and geometrical functions: the core-to-thickness ratio (CTR), porosity volume fraction (PVF), and porosity distribution function (PDF). It is worth mentioning that the theoretical expressions maintain good continuity and reliability under the influence of thermal conditions and system parameters of the proposed structures. Furthermore, considering the generation of thermal strain energy caused by thermal expansion of the structure in the normal direction, an improved analytical approach for determining thermal strain energy (TSE) in rectangular plate structures is then investigated by introducing the Green's nonlinear strain (GNS). Hamilton's principle is applied to derive the wave motion equations and analytical solutions for the wave dispersion relations are derived. Furthermore, accurate numerical simulation is performed and the solution is verified with data available in published resources. In addition, we present a systematic parametric analysis to examine the effects of porosity, configuration, power-law exponent (PLE), PVF, CTR, temperature, and wave number on the thermoelastic wave propagation behavior of FGMSRP.本文研究了功能梯度材料夹心矩形板的热弹性波传播特性。主要贡献在于部分修改了基本理论表达式和求解方法,提高了实际系统模型的准确性。建立了具有三种一般构型的解析模型。FGM层的孔隙度分布取决于组成材料的混合程度,以无孔隙度的FGM层为参考模型。通过精细的材料性能分析公式,可以解决FGM内部孔隙率的影响,FGM夹层结构(FGMSS)的温度依赖材料性能在厚度上保持连续性。这种改进的框架引入了孔隙度函数,包括三种不同的结构和几何函数:岩心厚度比(CTR)、孔隙体积分数(PVF)和孔隙度分布函数(PDF)。值得一提的是,在热条件和系统参数的影响下,理论表达式保持了良好的连续性和可靠性。此外,考虑到结构在法向热膨胀引起的热应变能的产生,引入格林非线性应变(GNS),研究了矩形板结构热应变能的改进解析方法。应用哈密顿原理推导了波浪运动方程,导出了波频散关系的解析解。最后进行了精确的数值模拟,并与文献资料进行了验证。此外,我们提出了一个系统的参数分析,以检验孔隙率、结构、幂律指数(PLE)、PVF、CTR、温度和波数对FGMSRP热弹性波传播行为的影响。Advances in suppression of structural vibration and sound radiation by flexural wave manipulationFeng Liu, Pengtao Shi, Yizhou Shen, Yanlong Xu, Zhichun Yangdoi:10.1016/j.tws.2024.111936弯曲波抑制结构振动和声辐射的研究进展The newly generated artificial structures, including phononic crystals, elastic metamaterials, acoustic black holes (ABHs) and elastic metasurfaces, can abnormally control wave propagations. In this paper, focusing on plate structures and from the perspective of the suppression of vibration and especially sound radiation by manipulating flexural waves, we give a thorough review of the advances of above-mentioned artificial structures, involving their extraordinary characteristics corresponding mechanisms of vibration and sound radiation suppression, design methods of phase-gradient elastic metasurfaces, and some representative works on suppressing vibration and sound radiation of plates by flexural wave manipulations. Additionally, we compare the advantages and disadvantages of these artificial structures in vibration and sound radiation suppression. Finally, we look forward to the prospects on vibration and sound radiation suppression of plates based on wave manipulations. This paper will provide a timely and practical assistance to academic and technical researchers in the field of vibration and noise reduction.声子晶体、弹性超材料、声黑洞和弹性超表面等新产生的人工结构可以异常地控制波的传播。本文以平板结构为研究对象,从操纵弯曲波抑制振动特别是声辐射的角度,综述了上述人工结构的研究进展,包括它们的特殊特性、相应的抑制振动声辐射的机理、相梯度弹性超表面的设计方法、并介绍了用弯曲波法抑制板材振动和声辐射的代表性工作。此外,我们还比较了这些人工结构在抑制振动和声辐射方面的优缺点。最后,展望了基于波处理的平板振动声辐射抑制研究的前景。本文将为减振降噪领域的学术和技术研究人员提供及时和实用的帮助。Evaluation of crush performance of extruded aluminum alloy tubes based on finite element analysis with ductile fracture modelingJung Yun Won, Chanyang Kim, Seojun Hong, Hyeong-Seop Yoon, Jong Kyu Park, Myoung-Gyu Leedoi:10.1016/j.tws.2024.111937 基于延性断裂建模的挤压铝合金管挤压性能有限元评价In this study, the crush performance of four aluminum extrusions are investigated through analysis based on finite element (FE) simulation incorporating experiment-numerical hybrid ductile fracture modeling. Tensile tests on standard and non-standard specimens, coupled with digital image correlation and FE analyses, are employed to establish constitutive models for the materials. The evaluation of crush performance is performed based on both axial crush test and corresponding 3-dimensional FE simulation, which could validate the employed plasticity and fracture laws and predict crush performance indicators with reliable accuracy. Additionally, FE modeling enables thorough analysis of highly non-proportional loading paths and potential crack initiation sites, with the crack formation mechanism elucidated through the evolution of a proposed damage variable. Furthermore, the modified crush performance indicators are newly suggested, which could explain the dependence on both the absorbed energy of tubular extrusion and properties of ductile fracture.采用基于有限元模拟的实验-数值混合韧性断裂模型分析方法,对4种铝型材的挤压性能进行了研究。通过标准和非标准试样的拉伸试验,结合数字图像相关和有限元分析,建立了材料的本构模型。基于轴向挤压试验和相应的三维有限元模拟进行了挤压性能评价,验证了塑性和断裂规律,预测了挤压性能指标,具有可靠的准确性。此外,有限元建模可以对高度非比例加载路径和潜在裂纹起裂部位进行深入分析,并通过提出的损伤变量的演化来阐明裂纹形成机制。此外,还提出了改进后的挤压性能指标,这可以解释管状挤压吸收能与韧性断裂性能的依赖关系。Polyurea elastomer for enhancing blast resistance of structures: Recent advances and challenges aheadHaojie Zhu, Chong Ji, Ke Feng, Jiangang Tu, Xin Wang, Changxiao Zhaodoi:10.1016/j.tws.2024.111938聚脲弹性体增强结构的抗爆炸能力:最近的进展和未来的挑战As an excellent anti-blast material, polyurea (PU) has been widely used in the reinforcement of masonry walls, RC structures, steel structures, and composite materials. The advances in the static and dynamic mechanical properties, dynamic constitutive models, and applications of PU in the field of blast resistance are reviewed. Although results have indicated the potential of PU in anti-blast reinforcement, the underlying mechanisms are not fully understood. Widely recognized mechanisms include shock wave induced ordering and hydrogen bonding changes in the hard domain, viscoelastic energy dissipation, and impedance matching between PU and matrix. Potential problems in the field of PU anti-blast transformation are summarized, and corresponding solutions are proposed.聚脲(PU)作为一种优良的抗爆材料,已广泛应用于砌体墙体、钢筋混凝土结构、钢结构、复合材料的加固。综述了聚氨酯的静、动态力学性能、动态本构模型及其在抗爆领域的应用研究进展。虽然结果表明PU在抗爆炸加固中的潜力,但其潜在机制尚未完全了解。广泛认识的机制包括激波诱导的硬畴有序和氢键变化、粘弹性能量耗散以及PU与基体之间的阻抗匹配。总结了聚氨酯抗爆改造领域存在的问题,并提出了相应的解决方案。来源:复合材料力学仿真Composites FEM

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