今日更新:Journal of the Mechanics and Physics of Solids 1 篇,International Journal of Plasticity 2 篇,Thin-Walled Structures 7 篇
A length-scale insensitive cohesive phase-field interface model: Application to concurrent bulk and interface fracture simulation in Lithium-ion battery materials
Wan-Xin Chen, Xiang-Long Peng, Jian-Ying Wu, Orkun Furat, Volker Schmidt, Bai-Xiang Xu
doi:10.1016/j.jmps.2024.106013
一种长度尺度不敏感内聚相场界面模型:在锂离子电池材料体裂和界面断裂模拟中的应用
A new cohesive phase-field (CPF) interface fracture model is proposed in this paper. It employs an exponential function for the interpolation of fracture energy between the bulk phase and the interface, and its effective interface fracture energy is solved based on the Euler–Lagrange equation of the phase-field theory and the consistency to the cohesive zone model (CZM) in the sharp interface concept. Comparison to other interface models in the literature clearly shows that the above energy consistency is essential to ensure the insensitivity of the results to the length-scale parameters for regularization of the crack surface and of the interface. The proposed interface model can be conveniently implemented via the relaxation solution of an Allen-Cahn equation, which offers high flexibility in handling structures of complicated interface topology. The proposed CPF interface model is employed further to derive a thermodynamically consistent chemo-mechanical model relevant to Lithium-ion battery materials. Finite-element simulations confirm the model’s ability to recapture the competition between bulk and interface fractures, while also demonstrate its merits of length-scale insensitivity and consistency with CZM results. The model is eventually applied in polycrystalline electrode particles, which are reconstructed from images with segmented interfaces, confirming the expected computational advantages and the length-scale insensitivity in multi-physical context.
提出了一种新的内聚相场(CPF)界面断裂模型。采用指数函数插值体相与界面之间的断裂能,基于相场理论的欧拉-拉格朗日方程和与尖锐界面概念中的内聚区模型(CZM)的一致性求解有效界面断裂能。与文献中其他界面模型的比较清楚地表明,上述能量一致性对于保证裂纹表面和界面正则化结果对长度尺度参数的不敏感性至关重要。所提出的界面模型可以方便地通过Allen-Cahn方程的松弛解实现,对于处理复杂的界面拓扑结构具有很高的灵活性。利用所提出的CPF界面模型进一步推导出与锂离子电池材料相关的热力学一致的化学力学模型。有限元模拟证实了该模型能够重现体裂缝和界面裂缝之间的竞争,同时也证明了其长度尺度不敏感和与CZM结果一致的优点。该模型最终应用于多晶电极颗粒,该模型由具有分割界面的图像重建,证实了预期的计算优势和多物理环境下的长度尺度不敏感性。
Quantitative comparison between experiments and crystal plasticity simulations using microstructural clones
Hojun Lim, Kaitlynn M. Fitzgerald, Timothy J. Ruggles, William G. Gilliland, Nicole K. Aragon, Jay D. Carroll
doi:10.1016/j.ijplas.2024.104186
显微组织克隆实验与晶体塑性模拟的定量比较
Crystal plasticity finite element (CP-FE) models are now extensively employed to investigate grain-scale deformation in crystalline materials. The fidelity of the model is derived from verification against experimental data; however, it is challenging to quantitatively compare regions of interest across different length scales using various experimental techniques. In this work, we compare CP-FE predictions of local and global mechanical responses to “Microstructural Clones” data, comprising multiple experimental datasets from microscopically identical quasi-2D crystal specimens. These multi-crystal specimens exhibit nearly identical grain morphologies, grain orientations, grain boundary characteristics, and similar dislocation arrangements. Such specimens enable multiple in-situ and ex-situ experiments on nominally identical samples, allowing for the control of several variables and the exploration of the impact of a single variable in a more scientifically rigorous manner. We use these clone experiments to compare texture evolution, surface strain fields, and failure behavior with CP-FE predictions. This procedure provides an objective and quantitative methodology to evaluate the agreement between the model and experimental data, and allows for the testing of various model parameters to improve the CP-FE model.
晶体塑性有限元(CP-FE)模型目前被广泛用于研究晶体材料的晶粒变形。通过对实验数据的验证,得到了模型的保真度;然而,使用各种实验技术在不同长度尺度上定量比较感兴趣的区域是具有挑战性的。在这项工作中,我们比较了局部和全局力学响应的CP-FE预测与“微观结构克隆”数据,包括来自微观上相同的准二维晶体样品的多个实验数据集。这些多晶样品表现出几乎相同的晶粒形态、晶粒取向、晶界特征和相似的位错排列。这些标本可以在名义上相同的样品上进行多次原位和非原位实验,从而可以控制多个变量,并以更严格的科学方式探索单个变量的影响。我们使用这些克隆实验来比较织构演变,表面应变场和破坏行为与CP-FE预测。该程序提供了一种客观和定量的方法来评估模型与实验数据之间的一致性,并允许测试各种模型参数以改进CP-FE模型。
Multi-element Segregation Strengthening and Doping Softening of S5 (210) [001] Symmetrically Tilted Grain Boundary in Ni-based Bicrystal
Hao Hu, Tao Fu, Shiyi Wang, Chuanying Li, Shayuan Weng, Deqiang Yin, Xianghe Peng
doi:10.1016/j.ijplas.2024.104219
ni基双晶中S5(210)的多元素偏析强化和掺杂软化[001]
Alloying is an economically efficient strategy to improve the thermal and mechanical stability of materials, which can also be applied to grain boundary (GB) in nanocrystalline materials to improve their mechanical properties. In this work, we investigated the mechanical properties and plastic deformation of bicrystal Ni samples with/without doping and segregation of multi-element (ME) atoms (including Co, Cr, Fe, and Mn atoms) using molecular dynamics (MD) simulations and Monte Carlo (MC) calculations at various temperatures. Each sample contains a Σ5 (210) [001] symmetric tilted GB. It was found that ME doping results in partial GB migration and softening, while ME segregation hinders GB migration, leading to strengthening. The softening and strengthening stem respectively from the distribution of ME atoms in the non-coincident site lattice (non-CSL) and in the coincident site lattice (CSL) sites. Furthermore, temperature affects the GB migration in ME-doped and ME-segregated samples through the compatibility of the ME atoms in GB. The results presented may contribute to understanding the mechanisms of strengthening and softening caused by ME doping and segregation at the atomic scale, and provide a perspective on the balance between strength and ductility.
合金化是一种经济有效的提高材料热稳定性和机械稳定性的策略,也可以应用于纳米晶材料的晶界,以改善其力学性能。在这项工作中,我们使用分子动力学(MD)模拟和蒙特卡罗(MC)计算,研究了掺杂/不掺杂双晶Ni样品的力学性能和塑性变形,以及多元素(ME)原子(包括Co, Cr, Fe和Mn原子)的偏析。每个样本包含一个Σ5(210)[001]对称倾斜GB。发现ME掺杂导致GB部分迁移和软化,而ME偏析阻碍GB迁移,导致强化。软化和强化分别源于ME原子在非重合点阵(non-CSL)和重合点阵(CSL)中的分布。此外,温度通过ME原子在GB中的相容性影响了ME掺杂和ME分离样品中GB的迁移。研究结果有助于在原子尺度上理解ME掺杂和偏析引起的强化和软化机制,并为强度和延性之间的平衡提供了一个视角。
Shear capacity of single- and double-layered gypsum board to steel stud screw connections in non-structural partitions
Saeed Mohebbi, Ehsan Bazarchi, Charles-Philippe Lamarche
doi:10.1016/j.tws.2024.112844
非结构隔板中单层和双层石膏板与钢螺柱连接的抗剪能力
Gypsum steel-stud partition walls are composed of light-gauge, cold-formed steel studs and gypsum boards attached with self-drilling screws. These non-structural elements are commonly used in volumetric modular building structures serving as partitions or exterior walls. Volumetric modular building structures are prefabricated, prefinished constructions where three-dimensional units, known as modules, are built in a factory and then transported to the construction site where they are placed and interconnected. The volumetric modules experience different loading scenarios during handling and transportation. While the modules may be designed to resist transportation and handling loads structurally, damage to nonstructural elements, such as gypsum board to stud connections, can still occur even under lower amplitude excitations. These non-structural damages, if not avoided, will require additional on-site repairs, leading to an increase in the overall costs of modular projects. This study investigates the shear capacity and damage mechanisms of gypsum board to steel stud screw connections. A series of experimental tests are performed to determine the capacity of these connections varying with the number of gypsum board layers (one- or two-layer), fastener edge distance and direction of loading (parallel or perpendicular to the edge). Finally, an analytical formulation was proposed to estimate the shear capacity of these connections. Results indicate that the distance of fasteners to the gypsum board edges dramatically affects the behaviour of these connections. The connection capacity at the damage state and the failure modes can fairly be predicted through the proposed analytical approach, showing a reasonable match with experimental results.
石膏钢螺柱隔墙是由轻规格、冷弯型钢螺柱和石膏板用自钻螺钉固定而成。这些非结构元素通常用于体量模块化建筑结构中,作为隔墙或外墙。体积模块化建筑结构是预制的,预制的建筑,其中三维单元(称为模块)在工厂中建造,然后运输到建筑工地,在那里它们被放置并相互连接。体积模块在搬运和运输过程中会经历不同的装载场景。虽然这些模块在结构上可以抵抗运输和处理载荷,但即使在较低振幅的激励下,非结构元件(如石膏板与螺柱连接)仍可能发生损坏。如果不能避免这些非结构性损坏,将需要额外的现场维修,从而导致模块化项目的总成本增加。研究了石膏板与钢螺柱连接的抗剪承载力及破坏机理。进行了一系列实验测试,以确定这些连接的容量随石膏板层数(单层或双层)、紧固件边缘距离和加载方向(平行或垂直于边缘)的变化而变化。最后,提出了一个分析公式来估计这些连接的抗剪能力。结果表明,紧固件到石膏板边缘的距离显著影响这些连接的行为。该分析方法能较好地预测损伤状态和破坏模式下的连接能力,与试验结果吻合较好。
Retrofitting of circular steel tubes against overall buckling using stiffened sleeves: Concept and experiments
Gang Shi, Shiqi Zhou, Shihao Wang, Huatian Zhao
doi:10.1016/j.tws.2024.112868
用加劲套筒加固圆钢管防止整体屈曲:概念和实验
This article introduces a novel retrofitting method for enhancing the stability of key compression members in steel space structures under load. The proposed method utilises lattice semi-circular sleeves with circular stiffeners, offering the advantages of easy construction and no welding. The outer sleeves were prefabricated in the factory and securely attached to the compression member onsite using bolts. To validate the concept, axial compressive tests were conducted on 12 full-scale specimens. The failure modes, load-displacement curves, and ultimate loading resistances of the specimens were determined using various parameters, including the initial load ratio, slenderness ratio, sleeve size, and stiffener spacing. In addition, 3D scanning was employed to examine the initial imperfections in the core tubes. The proposed retrofitting method significantly improved the overall stability of the compressive components, with the overall stability coefficient increasing from 20% to 344% on average. Three possible failure modes of the reinforced components were identified: overall buckling, delayed buckling, and full-section yield failures. Among the examined factors, the slenderness ratio of the inner tube, sleeve size, and stiffener spacing significantly affected the stability performance of the specimens, with average increases of 160%, 113% and 119%, respectively, in the overall stability coefficient. Furthermore, it is observed that the initial load ratio, when not greater than 0.5, had minimal impact on retrofitting efficiency, demonstrating the feasibility and effectiveness of the proposed method in improving structural member performance under various load conditions.
本文介绍了一种提高钢空间结构关键受压构件在荷载作用下稳定性的新型加固方法。该方法采用带圆形加强筋的点阵半圆套管,具有施工方便、无需焊接等优点。外套管在工厂预制,并在现场使用螺栓安全地连接到压缩构件上。为了验证这一概念,对12个足尺试件进行了轴向压缩试验。采用初始加载比、长细比、套筒尺寸、加强筋间距等参数确定了试件的破坏模式、荷载-位移曲线和极限荷载抗力。此外,采用三维扫描对岩心管的初始缺陷进行了检查。改进后的压缩构件整体稳定性显著提高,整体稳定系数从20%平均提高到344%。确定了加固构件的三种可能破坏模式:整体屈曲、延迟屈曲和全截面屈服破坏。其中,内筒长细比、套筒尺寸和加强筋间距对试件稳定性能影响显著,整体稳定系数平均分别增加160%、113%和119%。此外,当初始荷载比不大于0.5时,对改造效率的影响最小,证明了该方法在各种荷载条件下改善构件性能的可行性和有效性。
Axial-load response of CFSTs strengthened with textile-reinforced ECC: Testing, numerical analysis and design
Linghua Shen, Yuefan Li, Rui Wang, Hui Zhao, Qinghua Li, Shilang Xu, Yajun Zhang
doi:10.1016/j.tws.2024.112869
纺织增强ECC加固cfst的轴向荷载响应:试验、数值分析与设计
The combination of engineered cementitious composite (ECC) and fiber-reinforced polymer (FRP) textile systems has proven effective in improving the mechanical performance of structural members. This study focused on the compressive behaviours of concrete filled steel tube (CFST) columns reinforced with carbon fiber textile and ECC. A total of 22 columns were tested under axial compression, considering key parameters such as steel tube thickness, concrete grade, textile grid layer and textile grid size. The failure modes, load-axial deformation curves, and strain development were obtained. The test results indicated that using TR-ECC could effectively improve the ultimate strength of CFSTs, while increasing the grid size from 10 mm to 20 mm had a negligible impact on the ultimate strength. In addition, the stress state of the steel tube and the confining stresses provided by the steel tube and TR-ECC were analyzed based on circumferential and vertical strains. Furthermore, finite element models were established and validated by comparing them with experimental test results. Upon validation, a parametric investigation was conducted to examine the influence of the number of textile layer, textile grid size, material strength and steel ratio on the axial compression behaviours of the composite columns. Finally, simplified equations were developed to predict the axial bearing capacity of CFSTs reinforced with TR-ECC.
工程胶凝复合材料(ECC)与纤维增强聚合物(FRP)纺织系统的结合已被证明在改善结构构件的力学性能方面是有效的。本文主要研究了碳纤维织物和ECC加固钢管混凝土柱的抗压性能。考虑钢管厚度、混凝土等级、网格层数、网格尺寸等关键参数,共对22根柱进行了轴压试验。得到了试件的破坏模式、载荷-轴向变形曲线和应变发展曲线。试验结果表明,采用TR-ECC可以有效提高cfst的极限强度,而将网格尺寸从10 mm增加到20 mm对极限强度的影响可以忽略不计。此外,基于周向应变和垂直应变分析了钢管的应力状态以及钢管和TR-ECC提供的围应力。建立了有限元模型,并与试验结果进行了对比验证。在验证后,进行了参数化调查,以检查纺织层数,纺织网格尺寸,材料强度和钢比对复合柱轴压性能的影响。最后,建立了TR-ECC加固cfst轴向承载力的简化方程。
Experimental and numerical study of stainless steel built-up tubular sections subjected to End-Two-Flange loading
Yannan Jing, Ke Jiang, Shuai Li, Xiaoyi Lan, Yating Liang, Ou Zhao
doi:10.1016/j.tws.2024.112871
端部双法兰载荷作用下不锈钢组合管截面的试验与数值研究
This research investigates the web crippling behaviour and resistances of stainless steel built-up tubular sections subjected to End-Two-Flange (ETF) loading, underpinned by testing and numerical simulations. Experiments were conducted on 22 austenitic and duplex stainless steel built-up tubular section specimens, and each specimen was composed of two identical press-braked channel sections connected by self-tapping screws in a face-to-face manner. The results obtained from experiments were then adopted to validate finite element models. The validated finite element models were used to perform parametric studies to produce more numerical data. Based on the experimental and numerical data, the current design rules for stainless steel sections subjected to ETF loading, as specified in the European code and American specification, were assessed. The assessment results revealed that both design standards provided rather conservative and scattered failure load predictions. Finally, this study proposed a new design approach, offering substantially improved failure load predictions for austenitic and duplex stainless steel built-up tubular sections subjected to ETF loading.
本研究通过测试和数值模拟,研究了不锈钢组合管截面在端部双法兰(ETF)载荷下的腹板破坏行为和阻力。对22个奥氏体和双相不锈钢组合管状截面试件进行了试验,每个试件由两个相同的压制动槽段组成,通过自攻螺钉面对面连接。利用实验结果对有限元模型进行了验证。利用验证的有限元模型进行参数化研究,得到更多的数值数据。基于试验和数值数据,对欧洲规范和美国规范中规定的不锈钢截面受ETF荷载的现行设计规则进行了评估。评估结果表明,两种设计标准对失效荷载的预测均较为保守,且较为分散。最后,本研究提出了一种新的设计方法,大大改进了奥氏体和双相不锈钢组合管截面在ETF载荷下的失效载荷预测。
Capacity Prediction and Failure Mode Classification of Cold-Formed Steel Built-up Columns Using Machine Learning Methods
M.Numan Aloko, Raffaele De Risi, Flavia De Luca
doi:10.1016/j.tws.2024.112873
基于机器学习方法的冷弯型钢组合柱容量预测及失效模式分类
Combining two or more cold-formed steel (CFS) sections via fasteners to make built-up columns (BCs) is an innovative way to increase the loading capacity of CFS structural framing systems. Predicting the capacity of CFS-BCs can be challenging due to the variety of available cross-section geometries and the interaction of the connected columns. Current analytical and mechanical models in the literature have limitations in predicting the capacity and failure modes of CFS-BCs. Therefore, considering the limitations of conventional methods, five machine learning methods were trained and tested using an open-access CFS-BCs database compiled by the authors containing a data set of 1037 specimens to predict the axial capacity and classify the buckling failure modes of CFS-BCs. These techniques include Random Forest (RF), Extreme Gradient Boosting (XGB), Support Vector Machines (SVM), K-Nearest Neighbours (KNN), and Multilayer Perceptron (MLP) of artificial neural networks. Regression models were compared with the Direct Strength Method (DSM) in the North American Specification for the Design of Cold-Formed Steel Structural Members. The best regression and classification models were interpreted using the Shapley Additive Explanations (SHAP) and the Local Interpretable Model-Agnostic Explanations (LIME), respectively. The models' performance metrics indicated that MLP and XGB were the best in predicting axial capacity, while RF excelled in classifying failure modes, including interactive buckling. MLP and XGB showed better accuracy than DSM. Interpretation results indicated that machine learning models learn the underlying mechanics of designing compression CFS-BC members.
将两个或多个冷弯型钢通过紧固件组合成组合柱是提高冷弯型钢框架结构承载能力的一种创新方法。由于各种可用的横截面几何形状和连接柱的相互作用,预测cfs - bc的容量可能具有挑战性。目前文献中的分析和力学模型在预测CFS-BCs的能力和失效模式方面存在局限性。因此,考虑到传统方法的局限性,利用作者编制的开放存取CFS-BCs数据库(包含1037个试件数据集)对5种机器学习方法进行了训练和测试,以预测CFS-BCs的轴向承载力并对其屈曲破坏模式进行分类。这些技术包括随机森林(RF)、极端梯度增强(XGB)、支持向量机(SVM)、k近邻(KNN)和人工神经网络的多层感知器(MLP)。将回归模型与北美冷弯型钢构件设计规范中的直接强度法(DSM)进行了比较。最佳回归模型和分类模型分别采用Shapley加性解释(SHAP)和局部可解释模型不可知论解释(LIME)进行解释。模型的性能指标表明,MLP和XGB在预测轴向承载力方面效果最好,而RF在分类破坏模式(包括相互作用屈曲)方面表现出色。MLP和XGB的准确度优于DSM。解释结果表明,机器学习模型学习了设计压缩CFS-BC构件的基本机制。
Seismic performance of reinforcement-lapped square CFST column base
Yingying Yu, Yuanlong Yang, Lanhui Guo, Shiyong Jiang, Guojun Wang, Yohchia Frank Chen
doi:10.1016/j.tws.2024.112867
钢筋搭接方钢管混凝土柱基础抗震性能研究
This study proposes a square concrete-filled steel tubular (CFST) column base with lapped longitudinal reinforcements, and focuses on the investigation of its seismic performance experimentally and analytically. A quasi-static test on five reinforcement-lapped square CFST column bases is first conducted to evaluate the seismic performance, considering the key parameters of reinforcement ratio, lap length of lapped reinforcements, and configuration of the perfobond rib (PBL). The test results of failure modes, bearing capacity, ductility, energy dissipation capacity, and stress distribution, indicating that the proposed column base exhibits good seismic performance. The bearing capacity, ductility, and energy dissipation capacity are comparable to traditional embedded CFST column bases. To further investigate the force transfer path and stress distribution characteristics of the column bases, the software ABAQUS is used to establish a finite element model. Additionally, a calculation method for determining the combined compression-bending capacity is proposed. Validated against the experimental results, the proposed calculation method accurately predicts the bearing capacity of reinforcement-lapped square CFST column bases, making it suitable for practical applications.
提出了一种纵向搭接钢筋的方形钢管混凝土柱基础,并对其抗震性能进行了试验和分析研究。考虑配筋率、搭接钢筋搭接长度和全筋肋(PBL)结构等关键参数,首先对5个配筋搭接方形CFST柱基础进行了拟静力试验,对其抗震性能进行了评价。破坏模式、承载力、延性、耗能能力和应力分布试验结果表明,该柱基础具有良好的抗震性能。承载力、延性和耗能能力与传统的嵌入式钢管混凝土柱基础相当。为了进一步研究柱基座的传力路径和应力分布特征,利用ABAQUS软件建立了有限元模型。此外,还提出了一种确定复合抗弯承载力的计算方法。通过对试验结果的验证,所提出的计算方法能够较准确地预测钢筋搭接方钢管混凝土柱基础的承载力,具有较好的实际应用价值。
Seismic performance of double-sided plate-reinforced connections between steel beams and built-up box columns
Gang Shi, Sheng Jiang, Naizhou Zhang, Lintao Hou, Huatian Zhao
doi:10.1016/j.tws.2024.112872
钢梁与组合箱形柱间双面板加筋连接的抗震性能
Plate-reinforced connections (including cover-plate and flange-plate connections) are considered to be two types of improved seismic beam-to-column connections with the potential for widespread application. However, the existing research and analyses have revealed unreasonable aspects in the Chinese codes regarding the design provisions for plate-reinforced connections. In this study, an experimental study was conducted on two cover-plate and flange-plate double-sided beam-to-box column connection subassemblies at the full scale to evaluate their seismic performance. All specimens were fabricated using Q355 steel for beams, columns, and reinforcing plates and welded built-up sections for I-shaped beams and box columns. The applicability of Chinese code provisions, including the minimum panel zone resistance requirements and the flexural strength of beam web-to-column joints to plate-reinforced connections with box columns, was examined. The results showed that cover-plate and flange-plate connections had similar seismic performances. The four specimens satisfied the deformation and resistance requirements for special moment frames specified by AISC 341. Additionally, it was demonstrated that the current Chinese seismic design code may understate the resistance requirements of the panel zone and reduce the resistance of beam web-to-column joints and that removing beam web-to-column joints did not significantly affect the seismic performance of the connections.
板加固连接(包括盖板连接和法兰板连接)被认为是两种改进的抗震梁柱连接,具有广泛应用的潜力。然而,已有的研究和分析表明,我国规范对板加筋连接的设计规定存在不合理之处。在本研究中,对两个盖板和法兰板双面梁箱柱连接组件进行了全尺寸的试验研究,以评估其抗震性能。所有试件均采用Q355钢制作梁、柱和加强板,并焊接工字形梁和箱形柱的组合截面。对中国规范规定的适用性进行了检验,包括最小板区阻力要求和梁腹板-柱节点与箱形柱板加固连接的抗弯强度。结果表明,盖板连接与法兰板连接具有相似的抗震性能。四个试件均满足AISC 341规定的特殊弯矩框架的变形和阻力要求。此外,研究表明,现行的中国抗震设计规范可能低估了面板区域的阻力要求,降低了梁腹板与柱节点的阻力,并且去除梁腹板与柱节点对连接的抗震性能没有显着影响。