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【新文速递】2024年11月18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 2 篇,Journal of the Mechanics and Physics of Solids 2 篇,Thin-Walled Structures 3 篇

International Journal of Solids and Structures

Vibration characteristics of cylindrical shells with discontinuous connections based on the spectral element method

Kai Chai, Junfeng Liu, Jingjun Lou, Shuyong Liu

doi:10.1016/j.ijsolstr.2024.113148

基于谱元法的非连续连接圆柱壳振动特性研究

Common shell of revolution, such as cylindrical, conical, and spherical shells, are widely used in marine, aerospace, and other engineering fields due to their excellent support and pressure-resistant properties. Research on their vibration characteristics has progressed from single shells to composite shells, from ribbed shells to those with complex internal substructures, and from uniform to discontinuous connections. The discontinuities in wave propagation at the boundaries of discontinuously connected cylindrical shells result in highly complex equation of vibration control, leading to limited studies in this area. This study first models the uniform cylindrical shell and annular plate as spectral elements, using trigonometric and Bessel functions to describe displacement solutions and obtain vibration responses for arbitrary boundary conditions. Then, based on artificial virtual spring theory and the weighted least squares method, the discontinuous connection between the cylindrical shell and annular plate is modeled as a circumferentially varying stiffness distribution, leading to the derivation of dynamic stiffness matrices for both continuous and discontinuous connections. Finite element simulations are conducted using ABAQUS to analyze the vibration characteristics of the discontinuously connected cylindrical shell under free, clamped, and simply supported boundary conditions. Finally, an experimental setup is used to measure the vibration response under harmonic excitation and perform impedance testing with an impact hammer. The results show that the spectral element method accurately calculates the natural frequencies of the stiffened cylindrical shell, with an overall error of less than 2 %, while the maximum error for the experimental shell is 5.8 %.

常见的旋转壳体,如圆柱壳、锥形壳和球形壳,由于其优异的支撑和耐压性能,在船舶、航空航天和其他工程领域得到了广泛的应用。它们的振动特性研究已经从单壳发展到复合壳,从肋壳发展到具有复杂内部子结构的壳,从均匀连接发展到不连续连接。由于波浪在非连续连接圆柱壳边界处的传播不连续,导致振动控制方程非常复杂,导致该领域的研究有限。本研究首先将均匀圆柱壳和环形板建模为谱元,利用三角函数和贝塞尔函数描述位移解,得到任意边界条件下的振动响应。然后,基于人工虚拟弹簧理论和加权最小二乘法,将圆柱壳与环形板之间的不连续连接建模为周向变刚度分布,推导出连续连接和不连续连接的动刚度矩阵;利用ABAQUS软件进行有限元仿真,分析了自由边界、固支边界和简支边界条件下非连续连接圆柱壳的振动特性。最后,利用实验装置测量了谐波激励下的振动响应,并用冲击锤进行了阻抗测试。结果表明,谱元法准确地计算了加筋圆柱壳的固有频率,总体误差小于2 %,而实验壳的最大误差为5.8 %。


An analytical model for the phase transformation front propagation in superelastic SMA under impact tensile loading

Y. Wang, B. Hou, S. Roux, H. Zhao

doi:10.1016/j.ijsolstr.2024.113151

冲击拉伸载荷作用下超弹性SMA相变前沿扩展的解析模型

Shape-memory alloys (SMAs) exhibit superelastic behavior due to reversible phase transformations. Under dynamic (impact) loading, phase transformation is experimentally observed to occur along a band whose front propagates throughout the specimen. However, unlike the static case, the nucleation and propagation of these bands require further understanding. Recently, a Finite Element Method (FEM) simulation based on Thamburaja and Nikabdullah’s constitutive model successfully reproduced the experimental observations. In this study, the model is revisited in the specific case of a one-dimensional dynamic tension test, which allows for the derivation of an analytical closed-form one-dimensional stress–strain relation. When compared to FEM simulations of a single element, this analytical solution shows excellent agreement. From this closed form stress–strain relation, the propagation speed of the phase transformation shock front can be analytically computed. It also highlights that the shock front speed is primarily controlled by the strain reached after the complete transformation from the Austenite to the Martensite phase.

形状记忆合金(sma)由于可逆相变而表现出超弹性行为。在动态(冲击)载荷下,实验观察到相变发生在其前缘沿整个试样传播的条带上。然而,与静态情况不同,这些能带的成核和扩展需要进一步了解。最近,基于Thamburaja和Nikabdullah的本构模型的有限元模拟成功地再现了实验结果。在本研究中,该模型在一维动态张力试验的具体情况下被重新审视,它允许推导一个解析的封闭形式的一维应力-应变关系。与单单元有限元模拟结果比较,该解析解具有较好的一致性。根据这种封闭的应力-应变关系,可以解析计算相变激波前缘的传播速度。研究还表明,冲击前速度主要由奥氏体完全转变为马氏体后达到的应变控制。


Journal of the Mechanics and Physics of Solids

Stochastic generalized standard materials and risk-averse effective behavior

Jeremy Bleyer

doi:10.1016/j.jmps.2024.105952

随机广义标准材料与风险规避有效行为

In this work, we develop a theoretical formulation for describing dissipative material behaviors in a stochastic setting, using the framework of Generalized Standard Materials (GSM). Our goal is to capture the variability inherent in the material model while ensuring thermodynamic consistency, by employing the mathematical framework of stochastic programming. We first show how average behaviors can be computed using the expected value of the free energy and dissipation pseudo-potentials. We then introduce the concept of a risk-averse effective measure, which provides both an optimistic and a pessimistic estimate of the uncertain material behavior. To this end, we utilize the Conditional Value-at-Risk, a widely used risk measure in mathematical finance. We also demonstrate how these concepts can be extended to variational problems at the structure scale, allowing us to compute the effective response of a structure composed of a stochastic material.

在这项工作中,我们使用广义标准材料(GSM)的框架,开发了一个理论公式来描述随机设置中的耗散材料行为。我们的目标是通过采用随机规划的数学框架,在确保热力学一致性的同时,捕捉材料模型中固有的可变性。我们首先展示了如何使用自由能和耗散伪势的期望值来计算平均行为。然后,我们引入了风险规避有效度量的概念,它提供了不确定物质行为的乐观和悲观估计。为此,我们利用数学金融中广泛使用的风险度量——条件风险价值。我们还演示了如何将这些概念扩展到结构尺度上的变分问题,使我们能够计算由随机材料组成的结构的有效响应。


Graph neural networks for strut-based architected solids

I. Grega, I. Batatia, P.P. Indurkar, G. Csányi, S. Karlapati, V.S. Deshpande

doi:10.1016/j.jmps.2024.105966

基于结构实体的图神经网络

Machine learning methods for strut-based architected solids are attractive for reducing computational costs in optimisation calculations. However, the space of all realizable strut-based periodic architected solids is vast: not only can the number of nodes, their positions and the radii of the struts be changed but the topological variables such as the connectivity of the nodes brings significant complexity. In this work, we first examine the structure-property relationships of a large dataset of strut-based architected solids (lattices). We enrich the dataset by perturbing nodal positions and observe four classes of mechanical behaviour. A graph neural network (GNN) method is then proposed that directly describes the topology of the strut-based architected solid as a graph. The differentiating feature of our work is that key physical principles are embedded into the GNN architecture. In particular, the GNN model predicts fourth-order tensor with the required major and minor symmetries. The predictions are equivariant to rigid body and self-similar transformations, invariant to the choice of unit cell and constrained to provide a positive semi-definite stiffness tensor. We further demonstrate that augmenting the training dataset with nodal perturbations enables the model to better generalize to unseen lattice topologies.

基于结构实体的机器学习方法对于减少优化计算中的计算成本具有吸引力。然而,所有可实现的基于支柱的周期结构实体的空间是巨大的:不仅节点的数量、位置和支柱的半径可以改变,而且节点的连通性等拓扑变量也带来了极大的复杂性。在这项工作中,我们首先研究了基于结构实体(晶格)的大型数据集的结构-属性关系。我们通过扰动节点位置来丰富数据集,并观察到四类力学行为。然后提出了一种图神经网络(GNN)方法,将基于支柱的体系结构实体的拓扑结构直接描述为图。我们工作的不同之处在于关键的物理原理被嵌入到GNN架构中。特别是,GNN模型预测具有所需的主要和次要对称性的四阶张量。预测对刚体和自相似变换是等变的,对单元格的选择是不变的,并且约束于提供一个正的半定刚度张量。我们进一步证明,用节点扰动增加训练数据集使模型能够更好地推广到看不见的晶格拓扑。


Thin-Walled Structures

Innovative Auxetic Tubular Reinforced Metamaterial: Design and Mechanical Performance

Yinchuan He, Tingting Wang, Guoxing Lu, Li Wang, Kwong Ming Tse

doi:10.1016/j.tws.2024.112703

创新增强型管状超材料:设计与力学性能

In this study, we present the design, fabrication, and investigation of an innovative auxetic tubular reinforced (ATR) metamaterial. The mechanical properties and deformation characteristics of ATR metamaterials were comprehensively analyzed under quasi-static compression in both axial and radial directions. We conducted a comparative analysis between the ATR metamaterials and the original auxetic tubular (AT) metamaterials, employing both experimental and finite element methods. The findings indicate that the ATR structure surpasses the original AT structure in terms of mechanical properties during quasi-static compression in both directional orientations. Subsequently, a meticulous parametric analysis of the rotation angle of the reinforced straight ribs, a pivotal structural parameter, was conducted. The outcomes revealed that the rotation angle of the reinforced straight ribs, serving as a geometric parameter, can effectively influence the Poisson's ratio of the ATR structure. As the rotation angle of the reinforced straight rib increases, the ATR structure demonstrates superior energy absorption. The optimized ATR structure, in comparison to the original AT structure, showcases notable enhancements, exhibiting a 215% improvement in energy absorption (EA), a 62% increase in specific energy absorption (SEA), and a 46% rise in energy absorption efficiency (EAE) under axial quasi-static compression. Moreover, under radial quasi-static compression, the optimized ATR structure displays a remarkable improvement, featuring a 514% increase in EA, a 230% rise in SEA, and a 52% enhancement in EAE.

在这项研究中,我们提出了一种创新的消声管增强(ATR)超材料的设计、制造和研究。综合分析了ATR超材料在轴向和径向准静态压缩下的力学性能和变形特性。采用实验方法和有限元方法对ATR超材料与原始的AT超材料进行了对比分析。结果表明,在准静态压缩过程中,ATR结构在两个方向上的力学性能都优于原AT结构。随后,对加固直肋的旋转角度进行了细致的参数化分析,这是一个关键的结构参数。结果表明,加筋直肋的旋转角度作为几何参数,对ATR结构的泊松比有显著影响。随着增强直肋旋转角度的增大,ATR结构的吸能性能更好。优化后的ATR结构在轴向准静态压缩下的能量吸收(EA)提高了215%,比能吸收(SEA)提高了62%,能量吸收效率(EAE)提高了46%。此外,在径向准静态压缩下,优化后的ATR结构的EA提高了514%,SEA提高了230%,EAE提高了52%。


Programming morphological and mechanical performance of cyclic ori-kirigami via design-feasible parameter space

Ruoqi He, Yao Chen, Jiayao Shi, Yongtao Bai, Jian Feng

doi:10.1016/j.tws.2024.112706

基于设计可行参数空间的循环织构形态与力学性能规划

Recent advances in origami and kirigami have enabled the creation of unconventional structures that utilize precise folding and strategic cutting to achieve complex functionalities. In this study, we investigate the morphological and mechanical characteristics of one such structure, known as ori-kirigami. We establish the mapping between terminal folding states and parameter space, and analyze topologically feasible solutions for cyclic topology. The sensitivity of multi-stability to geometric parameters is investigated utilizing a nonlinear bar-and-hinge model. To facilitate automated design, analysis, and mechanical prediction, we propose a data-flow framework that supports the development of machine learning models for predicting mechanical responses. Additionally, symbolic regression is applied to derive a quantitative model for stiffness prediction. We anticipate that the findings of this work could open a path to engineering kirigami patterns for the design and fabrication of novel quasi-zero stiffness isolators, mechanical logic gates, and multistable shape-shifting structures.

折纸和基里格米的最新进展使得利用精确的折叠和战略切割来实现复杂功能的非常规结构的创造成为可能。在这项研究中,我们研究了一种被称为ori-kirigami的结构的形态和力学特征。建立了终端折叠态与参数空间的映射关系,分析了循环拓扑的拓扑可行解。利用非线性杆铰模型研究了多稳定性对几何参数的敏感性。为了促进自动化设计,分析和机械预测,我们提出了一个数据流框架,支持用于预测机械响应的机器学习模型的开发。此外,应用符号回归推导了刚度预测的定量模型。我们预计这项工作的发现可以为设计和制造新型准零刚度隔离器、机械逻辑门和多稳态变形结构的工程基里伽米模式开辟一条道路。


Compressive behavior of concrete jacketed in basalt TRM shell: experiments and predictions

Chenglin Wan, Jiyang Wang, Tao Wang, Fan Yang, Pinghuai Zhou

doi:10.1016/j.tws.2024.112709

玄武岩TRM壳套混凝土抗压性能:试验与预测

Numerous studies have investigated the behavior of textile reinforced mortar (TRM)-confined concrete, yielding various stress-strain models predominantly derived from fiber-reinforced polymer (FRP)-confined concrete. Yet, these models frequently overlook the intricate constitutive behavior of TRM materials and inadequately capture how TRM delivers its confinement effects. This often leads to inaccurate representation of the true characteristics of the confinement system, particularly the crucial role of mortar. This paper focuses on the impact of variations in textile layers and mortar matrix strength on the stress-strain behavior of basalt TRM (BTRM)-confined concrete, aiming to enhance our understanding of the confinement mechanism. Additionally, the study critically evaluates the key components of an existing analysis-oriented stress-strain model for FRP-confined concrete and introduces a refined version that more precisely depicts the behavior of confined concrete. This refined model integrates an identified confinement mechanism to provide accurate predictions of BTRM-confined concrete behavior. Our results reveal that low-grade mortar significantly decreases the actual confinement stiffness of BTRM jackets, inducing a steeper decline in the stress-strain curve, while high-strength mortar slightly diminishes the hoop rupture strain. To address the challenges of quantifying the complex confinement effect-compounded by the variable stress state and constitutive behavior of TRM-a novel coefficient, termed km, is introduced to gauge the influence of mortar strength on the confinement stiffness within the confining pressure equation. Predictive outcomes, including stress-strain and axial-to-lateral strain curves, show close alignment with experimental data, particularly in the slope at the plateau stage. This research significantly advances the quantitative understanding of TRM confinement effects and proposes the potential for designing more ductile structures using these materials, which could lead to enhanced resilience against seismic events and other structural challenges.

许多研究调查了纤维增强砂浆(TRM)约束混凝土的行为,得出了各种主要来自纤维增强聚合物(FRP)约束混凝土的应力-应变模型。然而,这些模型往往忽略了TRM材料复杂的本构行为,并没有充分捕捉到TRM如何提供其约束效应。这往往导致对约束系统真实特性的不准确表述,特别是迫击炮的关键作用。本文主要研究了纺织层数和砂浆基体强度的变化对玄武岩TRM (BTRM)约束混凝土应力-应变行为的影响,旨在增强我们对约束机制的理解。此外,该研究批判性地评估了现有frp约束混凝土面向分析的应力-应变模型的关键组成部分,并引入了一个更精确地描述约束混凝土行为的改进版本。这个改进的模型集成了一个确定的约束机制,以提供btrm约束混凝土行为的准确预测。研究结果表明,低等级砂浆显著降低了BTRM导管套的实际约束刚度,导致应力-应变曲线下降幅度更大,而高等级砂浆则略微降低了环向断裂应变。为了解决量化复杂约束效应的挑战-由trm的变应力状态和本构行为加剧-引入了一个新的系数,称为km,以衡量围压方程中砂浆强度对约束刚度的影响。预测结果,包括应力-应变和轴向-侧向应变曲线,显示与实验数据密切一致,特别是在高原阶段的斜坡。这项研究极大地推进了对TRM约束效应的定量理解,并提出了使用这些材料设计更具延展性的结构的潜力,这可能会增强对地震事件和其他结构挑战的弹性。



来源:复合材料力学仿真Composites FEM
ACTMechanicalSystemAbaqusDeform振动断裂非线性航空航天船舶理论材料控制试验纺织
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首次发布时间:2024-11-27
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【新文速递】2024年9月16日固体力学SCI期刊最新文章

今日更新:Journal of the Mechanics and Physics of Solids 1 篇,Mechanics of Materials 1 篇,International Journal of Plasticity 1 篇,Thin-Walled Structures 7 篇Journal of the Mechanics and Physics of SolidsA Chemo-Mechanical Model for Growth and Mechanosensing of Focal AdhesionJiashi Xing, Fuqiang Sun, Yuan Lin, Ze Gongdoi:10.1016/j.jmps.2024.105863聚焦黏附生长和机械传感的化学-力学模型Focal adhesion (FA), the complex molecular assembly across the lipid membrane, serves as a hub for physical and chemical information exchange between cells and their microenvironment. Interestingly, studies have shown that FAs can grow along the direction of contractile forces generated by actomyosin stress fibers and achieve larger sizes on stiffer substrates. In addition, the cellular traction transmitted to the substrate was observed to reach the maximum near the FA center. However, the biomechanical mechanisms behind these intriguing findings remain unclear. To answer this important question, here we first developed a one-dimensional (1D) chemo-mechanical model of FA where key features like adhesion plaque deformation, active contraction by stress fibers, force-dependent association/dissociation of integrin bonds connecting two surfaces, and substrate compliance have all been considered. Within this formulation, we showed that the rigidity-sensing capability of FAs originates from the deformability of stress fibers while the force-dependent breakage of integrin bonds leads to the appearance of the traction peak at the FA center. Furthermore, by extending the model into three-dimensional as well as incorporating assembly/dis-assembly kinetics of adhesion proteins, we also demonstrated how anisotropic stress/strain field within the adhesion plaque will be induced by the presence of contractile forces which eventually leads to the directional growth of the FA.Focal adhesion (FA)是一种跨越脂质膜的复杂分子组装,是细胞及其微环境之间物理和化学信息交换的枢纽。有趣的是,研究表明,FAs可以沿着肌动球蛋白应力纤维产生的收缩力方向生长,并在更硬的基质上实现更大的尺寸。此外,细胞传递到底物的牵引力在FA中心附近达到最大。然而,这些有趣发现背后的生物力学机制仍不清楚。为了回答这个重要的问题,我们首先建立了FA的一维化学力学模型,其中考虑了粘附斑块变形、应力纤维主动收缩、连接两个表面的整合素键的力依赖关联/解离以及基底顺应性等关键特征。在这个公式中,我们证明了FA的刚度感知能力来源于应力纤维的可变形性,而整合素键的力依赖断裂导致FA中心出现牵引峰。此外,通过将模型扩展到三维并结合粘附蛋白的组装/拆卸动力学,我们还展示了粘附斑块内的各向异性应力/应变场如何被收缩力的存在所诱导,最终导致FA的定向生长。Mechanics of MaterialsHybrid Modelling of Dynamic Softening using Modified Avrami Kinetics under Gaussian ProcessesNedjoua Matougui, Mohamed Imad Eddine Heddar, Oualid Chahaoui, John .Joseph Jonasdoi:10.1016/j.mechmat.2024.105153 高斯过程下基于改进Avrami动力学的动态软化混合建模This paper presents a new method of modelling that combines several approaches to anticipate the softening of nickel-niobium alloys during dynamic recrystallization (DRX). The study employs an extensive dataset obtained from hot torsion deformation tests conducted on high-purity nickel and six nickel-niobium alloys. The niobium concentration in these alloys varies from 0.01 to 10 wt. % [48]. The hybrid technique integrates the Avrami model to provide early predictions about the kinetics of recrystallization and then uses mechanistic modelling to assess the progression of softening caused by dynamic recrystallization (DRX). The integrated technique is improved by using Gaussian process regression analysis, which investigates the softening properties and offers useful insights into the effects of niobium additions on dynamic softening behaviour. This unique hybrid framework combines multiple modelling tools to reveal intricate connections impacted by solute addition, therefore enhancing our comprehension of the physical events that take place during the hot deformation of superalloys. The use of empirical, mechanistic, and machine learning methods in this hybrid model provides a more thorough and detailed investigation of DRX processes in these alloys.本文提出了一种新的建模方法,结合几种方法来预测镍铌合金在动态再结晶过程中的软化。该研究采用了从高纯度镍和六种镍铌合金的热扭转变形测试中获得的广泛数据集。这些合金中的铌浓度在0.01 ~ 10wt . %之间变化[48]。该混合技术集成了Avrami模型,提供了关于再结晶动力学的早期预测,然后使用力学模型来评估由动态再结晶(DRX)引起的软化过程。利用高斯过程回归分析对集成技术进行了改进,研究了软化性能,并为铌添加对动态软化行为的影响提供了有用的见解。这种独特的混合框架结合了多种建模工具,揭示了受溶质添加影响的复杂连接,从而增强了我们对高温合金热变形过程中发生的物理事件的理解。在这个混合模型中使用经验、机制和机器学习方法,为这些合金中的DRX过程提供了更彻底和详细的研究。International Journal of PlasticityDislocation accumulation-induced strength-ductility synergy in TRIP-aided duplex stainless steelJianquan Wan, Binbin He, Xusheng Yang, LingBing Kong, Xiaowei Zuo, Zengbao Jiaodoi:10.1016/j.ijplas.2024.104130 trip辅助双相不锈钢中位错积累引起的强度-塑性协同效应In this study, we investigate the intrinsic mechanism of intensive and progressive transformation-induced plasticity (TRIP) effects and their different strength-ductility synergies using a resource-efficient 15Cr-2Ni duplex stainless steel. The progressive TRIP material exhibits a ductility that is more than twice that of the intensive TRIP material, as well as, a larger product of the ultimate tensile strength and ductility. This is attributed to the dislocation accumulation caused by different grain sizes of strain-induced martensite depending on the stability of the γ phase, which determines the strength and work hardening of steel. When the stability is low, the γ phase is sensitive to loaded stress and transformed into dispersed fine martensite immediately after yielding at a high rate. It induces a sigmoid-shaped dislocation accumulation to an approximately 10-fold increase in the dislocation density at a limited strain, resulting in intensive work hardening and a large ultimate tensile strength. As the stability is adequate, the γ phase is transformed into coarse martensite laths with a high critical load stress, which is initiated from a delayed strain at an extremely low rate and steadily accelerated as the strain increases. This process induces a gradually increased dislocation accumulation to a 2–3-fold increase in the dislocation density at large strains, resulting in progressive work hardening and an excellent ductility.在本研究中,我们以资源高效的15Cr-2Ni双相不锈钢为材料,研究了密集和渐进式相变诱导塑性(TRIP)效应的内在机制及其不同的强度-塑性协同效应。渐进式TRIP材料的延展性是强化TRIP材料的两倍以上,并且具有更大的极限拉伸强度和延展性。这是由于γ相的稳定性决定了应变诱导马氏体的不同晶粒尺寸导致的位错积累,从而决定了钢的强度和加工硬化。当稳定性较低时,γ相对加载应力敏感,在高速率屈服后立即转变为分散的细小马氏体。在有限应变下,使位错密度增加约10倍,从而导致密集的加工硬化和较大的极限抗拉强度。当稳定性足够时,γ相转变为具有高临界载荷应力的粗马氏体板条,这一转变由延迟应变以极低的速率开始,并随着应变的增加而稳步加速。这一过程导致位错积累逐渐增加,大应变时位错密度增加2 - 3倍,导致逐渐加工硬化和良好的延性。Thin-Walled StructuresA semi-analytical method using auxiliary sine series for vibration and sound radiation of a rectangular plate with elastic edgesGuoming Deng, Xian Wu, Changxiao Shao, Songlin Zheng, Jianwang Shaodoi:10.1016/j.tws.2024.112460用辅助正弦级数半解析法研究弹性边缘矩形板的振动和声辐射This paper proposes an efficient semi-analytical method using auxiliary sine series for transverse vibration and sound radiation of a thin rectangular plate with edges elastically restrained against translation and rotation. The formulation, constructed by two-dimensional sine and/or cosine series, can approximately express the bending displacement, and calculate vibration and sound radiation under excitation of point force, arbitrary-angle plane wave, or diffuse acoustic field with acceptable accuracy. It is also applied for baffled or unbaffled conditions. A post-process program is developed to predict vibrating frequencies and modes, mean square velocity spectrum, and sound transmission loss via reduced-order integrals of radiation impedances. The method is validated by experiment and simulation results, demonstrating accurate and efficient computation using a single program for transverse vibration and sound radiation of a plate under different elastic boundary conditions and different excitations. Formulas given in this paper provide a basis for the code development on transverse vibration and sound radiation analysis of thin plates.本文提出了一种利用辅助正弦级数求解边缘受平移和旋转弹性约束的矩形薄板横向振动和声辐射的有效半解析方法。该公式由二维正弦和/或余弦级数构成,可以近似表示弯曲位移,计算点力、任意角度平面波或漫射声场激励下的振动和声辐射,精度可接受。它也适用于困惑或未困惑的情况。开发了一个后处理程序,通过辐射阻抗的降阶积分来预测振动频率和模态、均方速度谱和声音传输损失。实验和仿真结果验证了该方法的有效性,证明了单程序计算不同弹性边界条件和不同激励下板的横向振动和声辐射的准确性和有效性。本文给出的公式为薄板横向振动声辐射分析规范的制定提供了依据。Passing-through I-plates-to-SHS moment resisting joints subjected to symmetric bending momentsMouad Madhouni, Maël Couchaux, Mohammed Hjiaj, Alper Kanyilmazdoi:10.1016/j.tws.2024.112442对称弯矩作用下的贯通工字板- shs抗弯矩节点When using hollow structural section (HSS) members in multi-storey buildings, beam-to-column moment resisting connections’ design raises critical questions to tackle. With conventional welded and bolted joints’ response being generally very flexible, the design resistance becomes governed by a deformation criterion rather than a strength criterion. This underscores the necessity for smart reinforcement techniques. A widespread solution is the diaphragm approach, in which the stiffeners usually protrude over the tubular column. The solution of plates passing through the HSS column is another stiffening option which was studied recently for CHS, yet, SHS columns have not been subject to comparable scrutiny. The objective of this paper is to study experimentally, numerically, and analytically the mechanical behaviour of I-beam-to-SHS column moment resisting joints using passing through I-plates under symmetric bending moments. The testing of two full-scale specimens corroborates previous findings with CHS columns in the elastic regime. However, significant deviations were observed in the post-peak response, revealing new insights into the behaviour of SHS columns. Failure was due to progressive buckling of passing through plates and yielding of tube-wall in transverse compression. A finite element model using solid and contact elements is developed and validated against experimental data. This model underscores how loads are redistributed between the tube wall and passing plates. A simplified version of the FE model is used to perform a thorough parametric numerical analysis on 101 configurations expanding upon the experimental test database by varying geometrical parameters such as passing plate thickness, tube, and beam dimensions. Finally, an analytical model integrating the different components of the joint is proposed to evaluate the initial rotational stiffness and the bending resistance.在多层建筑中使用中空结构截面构件时,梁柱抗弯矩连接的设计提出了需要解决的关键问题。由于传统的焊接和螺栓连接的响应通常非常灵活,设计阻力由变形准则而不是强度准则来控制。这强调了智能加固技术的必要性。一种普遍的解决方案是横膈膜方法,在这种方法中,加强筋通常突出在管状柱之上。板通过HSS柱的解决方案是另一种加强的选择,这是最近研究的CHS,然而,SHS柱还没有受到可比的审查。本文的目的是通过实验、数值和分析研究工字梁- shs柱抗弯矩节点在对称弯矩作用下的力学行为。两个全尺寸标本的测试证实了以前的发现与CHS柱在弹性制度。然而,在峰后响应中观察到显著的偏差,揭示了对SHS柱行为的新见解。破坏是由于通过板的逐渐屈曲和管壁在横向压缩中的屈服。建立了基于实体单元和接触单元的有限元模型,并根据实验数据进行了验证。该模型强调了载荷如何在管壁和通过板之间重新分配。一个简化版的有限元模型,通过改变几何参数,如通过板的厚度,管,梁的尺寸,在实验测试数据库上扩展101配置进行了彻底的参数数值分析。最后,提出了一种结合不同构件的解析模型来计算节点的初始转动刚度和抗弯阻力。Wind-induced response of saddle membrane structure under typhoon wind field by Weather Research and Forecasting model and Computational Fluid DynamicsZiye Chen, Changjiang Liu, Weibin Huang, Wei Bao, Dong Li, Jian Liu, Chiyu Luo, Xiaowei Deng, Zhi Liudoi:10.1016/j.tws.2024.112445基于天气研究与预报模型和计算流体力学的鞍状膜结构在台风风场下的风致响应Currently, the research on wind-induced response of membrane structures focuses on the normal wind field, and there is little research on typhoon with greater disaster. In this paper, the wind-induced response of saddle membrane structures under typhoon is studied by numerical simulation. Firstly, the wind field information of typhoon is simulated according to the Weather Research and Forecasting model, and the information is used as the inlet boundary condition of Computational Fluid Dynamics. The vibration modal analysis is carried out, considering the influence of wind field intensity, wind direction angle, rise-span ratio, and pretension on the displacement of the membrane. The results show that the probability density curve of wind-induced response has a certain skewness. The saddle membrane structure has the largest vibration amplitude of the membrane at 0°wind direction angle, and the most unfavorable wind pressure value of the membrane is negative. In reducing the displacement of the membrane, the effect of reducing the wind-induced vibration response by increasing the rise-span ratio of the structure is better than that of the pretension. This paper reveals that the law of wind-induced response can provide a theoretical basis for the design of membrane structures against typhoons.目前对膜结构风致响应的研究主要集中在正常风场,对灾情较大的台风的研究较少。本文采用数值模拟方法研究了台风作用下鞍形膜结构的风致响应。首先,根据天气研究与预报模型对台风风场信息进行模拟,并将其作为计算流体力学的入口边界条件;考虑风场强度、风向角、升跨比、预紧力对膜位移的影响,进行了振动模态分析。结果表明,风致响应的概率密度曲线具有一定的偏度。鞍形膜结构在0°风向角时膜的振动幅值最大,膜的最不利风压值为负。在减小膜位移方面,增大结构的升跨比对减小风振响应的效果优于预张拉。揭示了风致响应规律可为膜结构抗台风设计提供理论依据。Nonlinear performance analysis and rapid prediction of out-of-plane deformation in graded honeycombsRui Yang, Shenghua Li, Shiyong Sun, Bin Niu, Ruixin Wang, Xiao chan Handoi:10.1016/j.tws.2024.112456 梯度蜂窝的非线性性能分析及面外变形快速预测Honeycomb structures, known for their excellent properties, are widely used in various advanced applications, including adaptive mirrors and soft wearable devices, due to their out-of-plane deformation capabilities. However, predicting the out-of-plane deformation of graded honeycombs remains challenging. A novel approach for rapidly predicting the out-of-plane deformation of graded honeycombs, considering their isotropic and nonlinear behavior, is presented in this study. Discrete material property spaces for seven honeycomb types were derived using a stiffness-updating nonlinear homogenization method and validated through digital image correlation (DIC) experiments. Prediction of nonlinear equivalent properties within two seconds was achieved by utilizing a hyperparameter optimization neural network (HONN). Graded honeycomb connection criteria (GHCC) were established to ensure performance stability. A rapid and accurate prediction method was enabled by the developed deformation-to-color mapping, which effectively bypasses costly numerical computations. Out-of-plane deformation is accurately forecasted by this approach, which also facilitates the transformation of flat surfaces into various shapes with distinct Gaussian curvatures, thereby opening new possibilities for large-scale deformable structures.蜂窝结构以其优异的性能而闻名,由于其面外变形能力,被广泛用于各种先进应用,包括自适应反射镜和软可穿戴设备。然而,预测梯度蜂窝的面外变形仍然具有挑战性。提出了一种快速预测梯度蜂窝面外变形的新方法,同时考虑了梯度蜂窝的各向同性和非线性特性。采用刚度更新非线性均匀化方法推导了7种蜂窝类型的离散材料特性空间,并通过数字图像相关(DIC)实验进行了验证。利用超参数优化神经网络(HONN)实现了两秒内非线性等效特性的预测。为了保证性能的稳定性,建立了梯度蜂窝连接准则(GHCC)。提出了一种快速准确的变形-颜色映射预测方法,有效地绕过了昂贵的数值计算。这种方法可以准确地预测面外变形,也有助于将平面转化为具有不同高斯曲率的各种形状,从而为大规模可变形结构开辟新的可能性。Compressive properties and biocompatibility of additively manufactured lattice structures by using bioactive materialsShuai Li, Tianqi Wang, Shuai Chen, Yingze Li, Yajun Zou, Bo Cao, Jiqiang Hu, Xiaojun Tan, Bing Wangdoi:10.1016/j.tws.2024.112469利用生物活性材料增材制造的晶格结构的压缩性能和生物相容性Porous bioactive materials were widely used in orthopedic implant fields because of their excellent mechanical properties and porous spaces. However, most porous types are predominantly stacked in two-dimensional configurations, which significantly limits their mechanical property range and adversely affects the modulus matching between the porous implants and surrounding bone tissues. Hence, various lattice structures were prepared using 3D printing technology with bioactive materials, and characterized by mechanical and biological tests. Numerical simulations were conducted to analyze the effect of relative density and geometric parameters on the equivalent compressive properties of the lattice structures. The results showed that the lattice structure exhibited a broad elastic modulus range, which can be adjusted to align with the mechanical properties of human cortical and cancellous bones, thereby helping to mitigate stress shielding in orthopedic implants. The biocompatibility of the 3D-printed solid materials was assessed in vitro using a cell counting assay kit-8 (CCK-8). The results indicated that poly-ether-ether-ketone (PEEK), carbon fiber reinforced PEEK (CFR/PEEK), nylon, and titanium (Ti) alloy all exhibited good biocompatibility, with no significant differences observed among the four materials. This study further enhances the understanding of bioactive lattice structures in the biomedical field and offers new possibilities for orthopedic repair.多孔生物活性材料以其优异的力学性能和多孔的空隙,在骨科植入体领域得到了广泛的应用。然而,大多数多孔类型主要以二维构型堆叠,这极大地限制了它们的力学性能范围,并对多孔植入物与周围骨组织之间的模量匹配产生不利影响。因此,利用生物活性材料的3D打印技术制备了各种晶格结构,并通过力学和生物学测试进行了表征。通过数值模拟分析了相对密度和几何参数对晶格结构等效压缩性能的影响。结果表明,该晶格结构具有较宽的弹性模量范围,可以根据人类皮质骨和松质骨的力学特性进行调整,从而有助于减轻骨科植入物的应力屏蔽。使用细胞计数试剂盒-8 (CCK-8)体外评估3d打印固体材料的生物相容性。结果表明,聚醚醚酮(PEEK)、碳纤维增强PEEK (CFR/PEEK)、尼龙和钛(Ti)合金均具有良好的生物相容性,且4种材料间无显著差异。该研究进一步提高了生物医学领域对生物活性晶格结构的认识,并为骨科修复提供了新的可能性。Deformation mechanism and life prediction model of titanium alloy laser-arc hybrid welded joint during fatigueHaizhou Li, Shengbo Li, Rui Su, Yongjie Liu, Sihai Luo, Liucheng Zhou, Qingyuan Wang, Hui Chendoi:10.1016/j.tws.2024.112470钛合金激光-电弧复合焊接接头疲劳变形机理及寿命预测模型The deformation mechanism and life prediction model of titanium alloy laser-arc hybrid welded joint during fatigue were studied. At the relatively small maximum cyclic stresses σmax (310 MPa to 350 MPa), the fatigue cracks initiated at the interface of lamellar α′ and needle-like α′ around the pore. At σmax = 370M Pa, the elongated lamellar α′ around the pore promoted fatigue crack propagation, leading to the formation of secondary cracks. At σmax = 390 MPa, the formation of two fatigue crack initiation locations and the occurrence of secondary cracks led to the maximum fatigue damage and the minimum fatigue life. In addition, the plastic deformation mainly occurred in β at σmax = 310M Pa, and it transformed into the phase interface of secondary α-β and granular β-α′ at σmax = 350M Pa. At σmax = 390M Pa, the main deformation forms were the cross-slip in β and the dislocations entanglement in α′. Finally, the fatigue life prediction model was established based on the equivalent cyclic stress, and the predicted fatigue life fell within a 3-fold error band.研究了钛合金激光-电弧混合焊接接头在疲劳过程中的变形机理和寿命预测模型。在相对较小的最大循环应力σmax(310 MPa 至 350 MPa)下,疲劳裂纹起始于孔隙周围的片状α′和针状α′的交界面。在 σmax = 370M Pa 时,孔隙周围拉长的片状α′促进疲劳裂纹扩展,导致次生裂纹的形成。当 σmax = 390 MPa 时,两个疲劳裂纹起始点的形成和二次裂纹的出现导致了最大的疲劳损伤和最小的疲劳寿命。此外,在 σmax = 310M Pa 时,塑性变形主要发生在 β 中,在 σmax = 350M Pa 时转变为次生 α-β 和粒状 β-α′ 的相界面。当 σmax = 390M Pa 时,主要变形形式为 β 中的交叉滑移和 α′ 中的位错纠缠。最后,根据等效循环应力建立了疲劳寿命预测模型,预测的疲劳寿命在 3 倍误差范围内。Acoustic emission and multiscale computation-guided tensile damage identification in woven composite laminates at cryogenic temperatures as low as 20 KLianhua Ma, Xiyan Du, Wei Zhou, Chuanjun Huang, Wentao Sun, Biao Wangdoi:10.1016/j.tws.2024.112464低至20k低温下复合材料层合板的声发射和多尺度计算导向拉伸损伤识别For laminated composite structures as key components of storage tanks serving at cryogenic temperature, it is crucial to identify the damage mechanisms for evaluating their mechanical properties and guiding structural design. In this work, the cryogenic tensile damage behavior of a thin-walled woven composite laminate was investigated through the acoustic emission (AE) monitoring and multiscale finite element (FE) computation at typical low temperatures of 153 K, 77 K and 20 K. We first established temperature-dependent constitutive laws for the microscale and mesoscale constituents of such composites based on experimental data, followed by the development of a hierarchical computational framework for modeling multiscale damage characteristics at different low temperatures. A fiber-optic acoustic emission measurement system was constructed to provide online monitoring of tensile damage of the woven composite laminates at cryogenic temperatures as low as 20K. The comparations were made between the predicted cryogenic damage characteristics and in-situ AE signal analysis, assisted by scanning electron microscope (SEM) observations. The computed cryogenic damage evolution closely matched the AE signal identification results. The results indicate that fiber breakage and matrix cracking are the dominant cryogenic damage modes, and that the different low temperatures exert significant effects on the properties of the epoxy matrix, yarns and composite laminates. The combination of the AE monitoring system and the computational scheme provides a valuable tool for evaluating structural integrity and guiding the microstructural design of composite laminates used in cryogenic environments.叠层复合材料结构作为低温储罐的关键部件,其损伤机理的研究是评价其力学性能和指导结构设计的关键。通过声发射(AE)监测和多尺度有限元(FE)计算,研究了薄壁编织复合材料层合板在典型低温(153 K、77 K和20 K)下的低温拉伸损伤行为。我们首先基于实验数据建立了这种复合材料的微尺度和中尺度成分的温度相关本构规律,然后开发了一个分层计算框架,用于模拟不同低温下的多尺度损伤特征。构建了一种基于光纤声发射的复合材料层合板低温拉伸损伤在线监测系统。通过扫描电镜(SEM)观察,将预测的低温损伤特征与现场声发射信号分析进行了比较。计算的低温损伤演化与声发射信号识别结果吻合较好。结果表明,纤维断裂和基体开裂是主要的低温损伤模式,不同低温对环氧基、纱线和复合材料层合板的性能有显著影响。声发射监测系统与计算方案的结合为低温环境下复合材料层合板的结构完整性评估和微观结构设计提供了有价值的工具。来源:复合材料力学仿真Composites FEM

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