【新文速递】2023年12月23日复合材料SCI期刊最新文章

今日更新：International Journal of Solids and Structures 1 篇，Mechanics of Materials 1 篇，Thin-Walled Structures 7 篇International Journal of Solids and StructuresStrain-gradient GBEM-based thermomechanical performance of architected, uniform and graded 2D materials and beam-type structuresDimitrios C. Rodopoulos, Nikolaos Karathanasopoulosdoi:10.1016/j.ijsolstr.2023.112603 基于应变梯度 GBEM 的建筑、均匀和分级二维材料及梁型结构的热力学性能The current contribution investigates the strain-gradient thermomechanical performance of architected materials and structures with uniform and graded inner material designs. To that scope, an integral representation of strain-gradients in thermoelasticity, along with its Galerkin Boundary Element Method (GBEM) implementation are elaborated. The formulation accounts for both mechanical and thermal strain-gradients for the first time. Thereupon, the complete strain-gradient response upon uniaxial tensile (UT) and thermal loading (Th) is analyzed, performing direct comparisons among the strain-gradient fields induced in each case and providing summarizing statistics that associate higher-order thermal and mechanical effects. The numerical framework is used as a basis for the quantification of the impact of the underlying structural patterns on the equivalent internal length parameters of architected beam-type structures under thermomechanical loads in the context of simple gradient theory. It is found that thermal loads relate to comparable, yet lower, internal length parameters with respect to the ones obtained for uniaxially tensioned structures with uniform inner cellular designs. Both internal length and temperature variation contributions determine the strain-gradient thermomechanical response of beam-type architected structures, for which, exact, higher-order equivalent 1D displacement field solutions are first derived. Thermally-induced, higher-gradient displacements are found to be comparable with the ones obtained in UT-loaded structures with uniform inner cellular topologies. Moreover, inner material gradings are found to be able to considerably mitigate higher-order effects, a sensitivity that is not reproduced in the UT loading case. The results provided, along with the numerical and analytical methodologies elaborated, set the basis for the thermomechanical strain-gradient analysis of advanced architected media well-beyond the designs here investigated.本论文研究了具有均匀和分级内部材料设计的建筑材料和结构的应变梯度热机械性能。为此，本文阐述了热弹性应变梯度的积分表示法及其伽勒金边界元素法（GBEM）的实现。该方法首次考虑了机械应变梯度和热应变梯度。因此，分析了单轴拉伸（UT）和热加载（Th）时的完整应变梯度响应，对每种情况下引起的应变梯度场进行了直接比较，并提供了与高阶热效应和机械效应相关的汇总统计数据。在简单梯度理论的背景下，该数值框架被用来量化底层结构模式对热机械载荷下架构梁型结构等效内部长度参数的影响。研究发现，热荷载与具有均匀内部蜂窝设计的单轴拉伸结构的内长参数具有可比性，但内长参数更低。内部长度和温度变化都决定了梁式结构的应变梯度热机械响应，为此，首先推导出了精确的高阶等效一维位移场解决方案。研究发现，热诱导的高梯度位移与具有均匀内部蜂窝拓扑结构的UT负载结构中获得的位移相当。此外，还发现内部材料分级能够大大减轻高阶效应，而这种敏感性在UT加载情况下无法再现。所提供的结果以及所阐述的数值和分析方法，为先进结构介质的热机械应变梯度分析奠定了基础，远远超出了本文所研究的设计范围。Mechanics of MaterialsCalibration of constitutive models using genetic algorithmsJoseph D. Robson, Daniel Armstrong, Joseph Cordell, Daniel Pope, Thomas F. Flintdoi:10.1016/j.mechmat.2023.104881使用遗传算法校准构成模型Constitutive models, describing material response to load, are an essential part of computational materials engineering. Semi-empirical constitutive laws including the Johnson–Cook and Zerilli–Armstrong models are widely used in finite element simulation for easy computability and rapid run time. The reliability of these models depends on accurate and reproducible fitting of parameters. This work presents a genetic algorithm (GA) based tool to fit parameters in constitutive models. The GA approach is capable of finding the global optimum parameter set in a robust, repeatable, and computationally efficient manner. It has been demonstrated that the obtained fits are better than those using traditional term-wise optimisation. Allowed to fit freely, the GA method will be likely to produce non-physical parameter values. However, by constraining the fit, the GA method can produce parameters that are physically reasonable and minimise the error when extrapolating to unseen data. Finally, the GA method may be used to choose between a variety of possible constitutive models based on a transparent best fit approach. The model has been demonstrated by using datasets from the literature for DH–36 steel and Ti–6Al–4V. This includes data from different studies, in which there are both random and systematic variations. The framework developed here is made freely available and modifiable, and may be extended to include other constitutive models as required.描述材料对载荷响应的构效模型是计算材料工程的重要组成部分。包括约翰逊-库克模型和泽里里-阿姆斯特朗模型在内的半经验构成定律因其易于计算和运行时间短而被广泛应用于有限元模拟。这些模型的可靠性取决于参数拟合的准确性和可重复性。这项工作提出了一种基于遗传算法（GA）的工具，用于拟合构成模型中的参数。GA 方法能够以稳健、可重复和计算高效的方式找到全局最优参数集。事实证明，所获得的拟合效果优于传统的按项优化法。如果允许自由拟合，GA 方法很可能会产生非物理参数值。然而，通过约束拟合，GA 方法可以产生物理上合理的参数，并在推断未见数据时将误差降至最低。最后，基于透明的最佳拟合方法，GA 方法可用于在各种可能的构成模型中进行选择。该模型已通过使用文献中有关 DH-36 钢和 Ti-6Al-4V 的数据集进行了验证。这包括来自不同研究的数据，其中既有随机变化，也有系统变化。此处开发的框架可免费使 用和修改，并可根据需要扩展到其他构成模型。Thin-Walled StructuresMechanical behavior of austenitic stainless steels produced by wire arc additive manufacturingMan-Tai Chen, Zhichao Gong, Tianyi Zhang, Wenkang Zuo, Yang Zhao, Ou Zhao, Guodong Zhang, Zhongxing Wangdoi:10.1016/j.tws.2023.111455线弧快速成型技术生产的奥氏体不锈钢的力学性能Wire arc additive manufacturing (WAAM) is an innovative technology with the potential to drive the transformation and upgrading of metallic manufacturing industry and construction sector. The advantages of WAAM technology in rapid manufacturing, design freedom, and energy saving have attracted attentions in the construction field. This research study focuses on investigating the microstructural and mechanical behavior of austenitic stainless steels produced by wire arc additive manufacturing through test programs. The stainless steel plates were first additively manufactured using cold metal transfer technology with three types of feedstock wires (ER304, ER308L, ER316L). Tensile coupon specimens and microstructural observation samples were extracted from the WAAM plates. The electron backscatter diffraction (EBSD) experiments were conducted to identify and analyze the microstructures of the WAAM austenitic stainless steels. Five test orientations, namely θ = 0˚, 30˚, 45˚, 60˚, 90˚ relative to the printing layer direction, were designed to investigate the mechanical properties anisotropy. Two types of specimen surface condition (milled type and as-built type) were considered to assess the impact of geometric undulation. The geometric features of the as-built specimens were obtained using 3D laser scanning. A total of 60 tensile tests with the aid of digital image correlation (DIC) system were conducted to obtain the stress-strain responses of the WAAM austenitic stainless steels. The mechanical properties anisotropy of the WAAM austenitic stainless steels was analyzed in detail.线弧快速成型技术（WAAM）是一项创新技术，具有推动金属制造业和建筑业转型升级的潜力。WAAM 技术在快速制造、自由设计和节能方面的优势已引起建筑领域的关注。本研究主要通过测试程序研究线弧快速成型技术生产的奥氏体不锈钢的微观结构和力学行为。首先采用冷金属转移技术，使用三种原料线材（ER304、ER308L、ER316L）对不锈钢板进行增材制造。从 WAAM 钢板中提取了拉伸试样和微观结构观察样品。电子反向散射衍射（EBSD）实验用于识别和分析 WAAM 奥氏体不锈钢的微观结构。设计了五个测试方向，即相对于印刷层方向的 θ = 0˚、30˚、45˚、60˚、90˚，以研究力学性能各向异性。为评估几何起伏的影响，考虑了两种类型的试样表面条件（铣削型和原样型）。竣工试样的几何特征是通过三维激光扫描获得的。借助数字图像相关（DIC）系统共进行了 60 次拉伸试验，以获得 WAAM 奥氏体不锈钢的应力-应变响应。详细分析了 WAAM 奥氏体不锈钢的机械性能各向异性。Wind loads on structural members of rack-supported warehousesAntonino Maria Marra, Bernardo Nicese, Tommaso Massai, Gianni Bartolidoi:10.1016/j.tws.2023.111458支架支撑仓库结构构件的风荷载Rack-supported warehouses represent a modern typology of storage racks in which cladding panel weight and corresponding applied loads, such as wind or snow load, are supported by storage racks, in addition to pallet load and seismic action. Although this structural system allows for reducing the amount of structural steel, the uprights and beams, composing each rack, are directly exposed to the wind during the earliest erection phases. This load condition may govern the design of the uprights or that of temporary bracings. Wind load estimation requires the knowledge of the aerodynamic coefficients of each structural member section, for any angles of wind incidence. Unlike any common structural steelwork section, no data are available in the literature for RSW member sections. The current work represents a first step to cover this lack in the literature by reporting the results of an extensive wind tunnel campaign carried out on several portions of uprights and beams commonly designed and produced for RSWs. The results highlight the need for wind tunnel tests on RSW member sections when the producers can no longer afford an overestimation of the wind load. In addition, conservative values of the aerodynamic coefficients are provided for preliminary wind load estimations or temporary bracings design. Empirical relationships for the aerodynamic coefficients by changing an equivalent side ratio are also reported. Finally, design recommendations are provided by highlighting a critical structural configuration during the early erection phases of RSWs that govern the design of the uprights or temporary bracings. A worked example is then developed to clarify the application of the present results in the definition of wind loads.货架支撑仓库代表了现代仓储货架的一种类型，其中除了托盘载荷和地震作用外，包层板的重量和相应的外加载荷（如风载荷或雪载荷）都由货架支撑。虽然这种结构系统可以减少结构钢的用量，但组成每个货架的立柱和横梁在最早的安装阶段会直接暴露在风中。这种荷载条件可能会影响立柱或临时支撑的设计。风荷载估算需要了解每个结构部件在任何风入射角度下的空气动力系数。与任何常见的钢结构截面不同，文献中没有关于 RSW 构件截面的数据。目前的工作是弥补文献不足的第一步，报告了对 RSW 通常设计和生产的几部分立柱和横梁进行广泛风洞试验的结果。研究结果突出表明，当生产商无法再承受高估的风荷载时，有必要对 RSW 构件截面进行风洞试验。此外，还为初步风荷载估算或临时支撑设计提供了空气动力系数的保守值。还报告了通过改变等效侧比来计算空气动力系数的经验关系。最后，通过强调 RSW 早期安装阶段的关键结构配置，提供了设计建议，这些配置对直立支柱或临时支撑的设计具有指导作用。随后，还通过一个工作示例来说明本成果在风荷载定义中的应用。AAC-Block Walls with Surface Application of Non-Structural Plastering Materials as Newly Configured and Improved Structures Subjected to ShearingMarta Kałużadoi:10.1016/j.tws.2023.111459表面使用非结构性抹灰材料的 AAC 砌块墙，作为受剪切力影响的新配置和改进结构This research evaluates the use of non-structural materials, in the form of plastering grids and adhesive mortars, to create a newly configured structure with better shear properties than the original one, i.e. AAC blocks walls. Four types of glass fibre grid and two adhesive mortars were used. The results of 35 tested models subjected to diagonal compression show significantly improved performance by avoiding brittle failure, providing a significant increase in strength and ensuring relatively safe working conditions at large deformations. The best improvement in shear properties provided a relatively ‘weak’ grid with small openings and a highly deformable mortar.这项研究评估了非结构材料（抹灰网格和粘合砂浆）的使用情况，以创建一种新配置的结构，其剪切性能比原来的结构（即 AAC 砌块墙）更好。共使用了四种玻璃纤维网格和两种粘合砂浆。对 35 个模型进行对角压缩测试的结果表明，通过避免脆性破坏、显著提高强度和确保大变形时相对安全的工作条件，其性能得到了明显改善。剪切性能改善最好的是具有小开口的相对 "弱 "网格和高变形砂浆。Micromechanical study of intragranular stress and strain partitioning in an additively manufactured AlSi10Mg alloyV. Romanova, R. Balokhonov, A. Borodina, O. Zinovieva, E. Dymnich, S. Fortuna, A. Shugurovdoi:10.1016/j.tws.2023.111464 添加式制造的 AlSi10Mg 合金晶内应力和应变分配的微观力学研究This study addresses the effect of a cellular-dendritic microstructure on the intragranular deformation behavior of an additively manufactured AlSi10Mg alloy. Experimental investigations have revealed the Al dendritic cells with a characteristic size of several hundred nanometers. The cells are decorated by a thin eutectic layer which consists of an aluminum matrix reinforced by silicon nanoparticles. Based on the experimental data, a set of micromechanical models are constructed and implemented in finite-element calculations. The constitutive behavior of an aluminum phase is described in terms of anisotropic elasticity to take into account the crystal lattice effects. Calculation results are analyzed and discussed with the main focus being placed on the effect of microstructure-resolved stress and strain partitioning between Al and Si phases. The silicon content is shown to impact the range of stress variation at the intragranular scale and the places of stress concentration in the Al phase. The eutectic layer behaves as a metal matrix composite where reinforcing silicon particles restrict deformation of the aluminum matrix.本研究探讨了细胞树枝状微结构对添加剂制造的 AlSi10Mg 合金晶内变形行为的影响。实验研究发现，铝树枝状细胞的特征尺寸为几百纳米。这些细胞由薄共晶层装饰，共晶层由硅纳米颗粒增强的铝基体组成。根据实验数据，构建了一套微机械模型，并在有限元计算中实施。铝相的构成行为用各向异性弹性来描述，以考虑晶格效应。对计算结果进行了分析和讨论，重点关注微观结构应力和应变在铝相和硅相之间分配的影响。结果表明，硅含量会影响晶粒内部的应力变化范围以及铝相的应力集中位置。共晶层表现为金属基复合材料，其中强化硅颗粒限制了铝基体的变形。Experimental and Numerical Investigation on Mechanical and Fatigue Performance of Corroded Q690D High-Strength SteelLiang Zong, Heng Liu, Jiaxuan Wang, Yang Dingdoi:10.1016/j.tws.2023.111466锈蚀 Q690D 高强度钢机械和疲劳性能的实验和数值研究As a prevalent environmental factor in the service process of steel structures, corrosion have a significant impact on the mechanical and fatigue properties of steel, thus deteriorating service safety. In this article, focused on corroded Q690D high-strength steel, experimental and numerical investigations have been performed. Electrolytic accelerated corrosion experiments were conducted, and 3D surface morphology measurements were employed to analyse the surface properties of specimens with various corrosion degrees. Mechanical and high-cycle fatigue tests were carried out on the corroded specimens, then degradation models between the mechanical behaviours and corrosion characteristics were established. Furthermore, the fatigue damage evolution model of Q690D high-strength steel was calibrated based on continuum damage mechanisms (CDM), and numerical simulations of the corroded specimen corresponding to the monotonic tensile tests and high cycle fatigue tests were conducted. The results show that with the increase of corrosion degree, the elastic modulus, yield stress, and tensile stress would decrease, and the fatigue performance would deteriorate. Corrosion has a greater effect on the fatigue life of long-life range and the slopes of the S-N curves after corrosion are more uniform. With the CDM parameters of non-corroded Q690D and the numerical model with consideration of surface roughness, the fatigue life of corroded Q690D could be well simulated.锈蚀是钢结构服役过程中普遍存在的环境因素，对钢材的力学性能和疲劳性能有重大影响，从而降低服役安全性。本文以锈蚀的 Q690D 高强度钢为研究对象，进行了实验和数值研究。进行了电解加速腐蚀实验，并采用三维表面形貌测量来分析不同腐蚀程度试样的表面特性。对腐蚀试样进行了机械和高循环疲劳试验，然后建立了机械行为与腐蚀特性之间的退化模型。此外，基于连续损伤机理（CDM）校准了 Q690D 高强度钢的疲劳损伤演化模型，并对腐蚀试样进行了与单调拉伸试验和高循环疲劳试验相对应的数值模拟。结果表明，随着腐蚀程度的增加，弹性模量、屈服应力和拉伸应力都会降低，疲劳性能也会恶化。腐蚀对长寿命范围的疲劳寿命影响更大，腐蚀后的 S-N 曲线斜率更均匀。利用未腐蚀 Q690D 的 CDM 参数和考虑表面粗糙度的数值模型，可以很好地模拟腐蚀 Q690D 的疲劳寿命。Performance Assessment of Steel Frame Buildings with Hybrid Self-centering Braces under Extremely Rare Far-field EarthquakesFei Shi, Wenlang Yuan, Osman E. Ozbulut, Chao Zhang, Yun Zhoudoi:10.1016/j.tws.2023.111456采用混合自定心支撑的钢结构建筑在极罕见远场地震下的性能评估This paper investigates the seismic performance enhancement of steel frame buildings using a novel hybrid self-centering braces (HSBs) under extremely rare earthquake events. The hybrid self-centering brace consists of shape memory alloy (SMA) cables and viscoelastic (VE) dampers. A prototype bracing system is designed and fabricated to explore its basic mechanical behavior and working mechanism under cyclic loading, with a focus on its failure modes under large deformation loading condition. A multi-material mechanical model is developed to capture the mechanical behavior and failure of the HSB. Furthermore, five steel frame buildings with different parameterized HSBs are designed and modeled in OpenSees. Nonlinear dynamic analyses and incremental dynamic analyses are conducted on the five case-study frames using 44 far-field ground motions. The risk-based seismic performances of steel buildings with HSB are evaluated to assess the performance of HSB during extremely rare seismic events. The results show that the hybrid self-centering brace exhibits excellent self-centering and energy dissipation capabilities with the maximum equivalent viscous damping ratio reaching 9.4%. Even under large deformations, VE dampers continue to work effectively after the failure of SMA cables, demonstrating remarkable redundancy. Numerical simulations further reveal that the redundancy of HSB can improve the structural seismic resilience in terms of inter-story drift ratio, residual drift, and floor absolute acceleration. The higher the redundancy of HSB in the case-study frames, the smaller the seismic response and mean annual frequency of exceedance of the engineering demand parameters, thereby indicating a significant improvement in seismic performance.本文研究了在极罕见地震事件下，使用新型混合自定心支撑（HSB）提高钢结构建筑抗震性能的问题。混合自定心支撑由形状记忆合金（SMA）缆索和粘弹性（VE）阻尼器组成。设计并制造了一个原型支撑系统，以探索其在循环加载下的基本机械行为和工作机制，重点研究其在大变形加载条件下的失效模式。开发了一个多材料力学模型，以捕捉 HSB 的力学行为和失效。此外，还在 OpenSees 中设计和模拟了五栋具有不同参数化 HSB 的钢框架建筑。利用 44 种远场地震动对五个案例研究框架进行了非线性动力分析和增量动力分析。评估了采用 HSB 的钢结构建筑的抗震性能风险，以评估 HSB 在极罕见地震事件中的性能。结果表明，混合自定心支撑具有出色的自定心和消能能力，最大等效粘性阻尼比达到 9.4%。即使在大变形情况下，VE 阻尼器也能在 SMA 电缆失效后继续有效工作，显示出显著的冗余性。数值模拟进一步表明，HSB 的冗余性可以在层间漂移比、残余漂移和楼层绝对加速度方面提高结构的抗震能力。在案例研究框架中，HSB 的冗余度越高，地震响应和工程要求参数的年平均超标频率就越小，从而表明抗震性能得到了显著改善。Microscale modeling of the ductile fracture behavior of thin stainless steel sheetsMehdi Karimi Firouzjaei, Hassan Moslemi Naeini, Mohammad Mehdi Kasaei, Mohammad Javad Mirnia, Lucas FM da Silvadoi:10.1016/j.tws.2023.111457不锈钢薄板韧性断裂行为的微尺度建模This study aims to model the fracture behaviour of thin stainless steel sheets in the microscale, which are widely used in the manufacturing of thin-walled structures such as bipolar plates, while considering the effects of geometry and grain size. To achieve this, 304 austenitic stainless steel with two different thicknesses is heat-treated to obtain samples with distinctive grain sizes. Uniaxial tensile tests and cup drawing tests are performed on the resulting samples, and the fracture strains are measured using a digital image correlation system. The morphology of fracture surfaces is also analysed to understand fracture mechanisms in the microscale. A new ductile fracture model based on the normalized Cockcroft-Latham criterion is developed to take the size effect into account, which is then applied in finite element analysis to predict damage evolution and fracture initiation during the tests. The results reveal a significant reduction in the fracture strain with decreasing sheet thickness and increasing grain size. Furthermore, the fracture mode changed from tensile fracture of a polycrystalline metal to shear fracture of a single-crystal metal as the number of grains across the thickness decreased. It is confirmed that the proposed model accurately replicates the decrease of the fracture strain as the plastic deformation scaled down to the microscale and successfully predicts the displacement at the onset of fracture under different loading conditions. Based on these results, it can be concluded that the proposed model has great potential for predicting fracture in microforming processes.不锈钢薄板广泛用于制造双极板等薄壁结构，本研究旨在建立微尺度不锈钢薄板断裂行为模型，同时考虑几何形状和晶粒大小的影响。为此，对两种不同厚度的 304 奥氏体不锈钢进行了热处理，以获得具有不同晶粒尺寸的样品。对所得样品进行单轴拉伸试验和杯状拉伸试验，并使用数字图像相关系统测量断裂应变。此外，还对断裂表面的形态进行了分析，以了解微观尺度的断裂机制。基于归一化 Cockcroft-Latham 准则开发了一种新的韧性断裂模型，将尺寸效应考虑在内，然后将其应用于有限元分析，以预测试验过程中的损伤演变和断裂起始。结果表明，随着薄片厚度的减小和晶粒尺寸的增大，断裂应变明显减小。此外，随着厚度上晶粒数量的减少，断裂模式也从多晶金属的拉伸断裂转变为单晶金属的剪切断裂。研究证实，所提出的模型准确地复 制了塑性变形缩小到微尺度时断裂应变的减小，并成功地预测了不同加载条件下断裂发生时的位移。基于这些结果，可以得出结论：所提出的模型在预测微成形过程中的断裂方面具有巨大潜力。来源：复合材料力学仿真Composites FEM