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【新文速递】2024年7月4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 5 篇,Journal of the Mechanics and Physics of Solids 2 篇,Mechanics of Materials 1 篇,International Journal of Plasticity 1 篇,Thin-Walled Structures 2 篇

International Journal of Solids and Structures

Error analysis of deformation assumptions for the in-plane torsion test of sheet metal

Peter G. Gruber, Jagoba Lekue, Leopold Wagner, Thomas Gross, Stefan Sieberer, Martin Schagerl

doi:10.1016/j.ijsolstr.2024.112945

板材平面扭转试验变形假设误差分析

The in-plane torsion test offers an alternative to common parameter identification tests, needed for material modeling of sheet metal. As compared to common tests during material characterization, higher equivalent plastic strains are achieved, and kinematic hardening laws are calibrated at higher strains. In addition, it also allows to determine fracture strains in pure shear. In this contribution, we focus on a well known approach utilizing optical measurement of a scribed line as indicator for the shear deformation. The underlying mathematical model is studied, and an error analysis is provided regarding the approximation of stress and strain measures. Thereby the assumption of simple shear deformation is found to be accurate for specimen of the assumed geometrical and material properties. The presented approach, however, can be easily adapted to derive error estimates also in cases of differing geometry or material.

面内扭转试验为金属板材料建模所需的普通参数识别试验提供了一种替代方法。与材料表征过程中的普通试验相比,可以获得更高的等效塑性应变,并在更高应变下校准运动硬化定律。此外,它还可以确定纯剪切下的断裂应变。在本文中,我们将重点介绍一种众所周知的方法,即利用光学测量刻线作为剪切变形的指标。我们对基本数学模型进行了研究,并对应力和应变测量的近似值进行了误差分析。因此,对于假定几何和材料特性的试样,简单剪切变形的假设是准确的。不过,所提出的方法也可以很容易地适用于不同几何形状或材料情况下的误差估算。


Numerical analysis of ductile fracture in stretch bending of AA6061-T6 aluminum alloy sheet using GTN damage model

Maziar Khademi, Mohammad Javad Mirnia, Hassan Moslemi Naeini

doi:10.1016/j.ijsolstr.2024.112947

使用 GTN 损伤模型对 AA6061-T6 铝合金板材拉伸弯曲中的韧性断裂进行数值分析

In this paper, the original and shear-modified GTN ductile fracture criteria are utilized to investigate the fracture behavior of the AA6061-T6 aluminum alloy sheet during the stretch bending process. An appropriate calibration strategy is presented to find the unknown coefficients of the fracture models. In this way, different tension tests such as uniaxial tension, plane strain, notched tension, and shear tension specimens are utilized. Results show that the shear-modified GTN model calibrated by the mentioned tension tests is able to predict the onset of fracture of the stretch bending process with a 5% error, while the original GTN model, calibrated by the uniaxial tension is unable to predict the fracture properly. Since the accuracy of fracture prediction depends on the stress state, the effects of the calibration test on onset of fracture were investigated. It is shown that using the original GTN model with a proper calibration test (plane strain tension) can achieve a good accuracy with 3.5% error in the stretch bending process. In addition, results show that any change in the friction coefficient and bending radius in the stretch bending process can lead to different fracture behavior. Several investigations are carried out to examine the evolution of damage and displacement of fractures in the stretch bending process under different forming conditions.

本文利用原始和剪切修正的 GTN 延展性断裂准则来研究 AA6061-T6 铝合金板材在拉伸弯曲过程中的断裂行为。本文提出了一种适当的校准策略,以找到断裂模型的未知系数。通过这种方法,利用不同的拉伸试验,如单轴拉、平面应变、缺口拉和剪切拉伸试样。结果表明,通过上述拉伸试验校准的剪切修正 GTN 模型能够预测拉伸弯曲过程中的断裂起始点,误差为 5%,而通过单轴拉伸校准的原始 GTN 模型则无法 正确预测断裂。由于断裂预测的准确性取决于应力状态,因此研究了校准试验对断裂发生的影响。结果表明,在拉伸弯曲过程中,使用原始 GTN 模型并进行适当的校准试验(平面应变拉伸)可获得良好的精度,误差仅为 3.5%。此外,结果表明,在拉伸弯曲过程中,摩擦系数和弯曲半径的任何变化都会导致不同的断裂行为。在不同的成形条件下,对拉伸弯曲过程中断口的损伤和位移演变进行了多项研究。


Influence of elastic and toughness anisotropy on crack initiation

Thomas Duminy, Venkat Ayyalasomayajula, Aurélien Doitrand, Sylvain Meille

doi:10.1016/j.ijsolstr.2024.112950

弹性和韧性各向异性对裂纹起始的影响

The influence of elastic and toughness anisotropy on crack initiation in V-notched specimens is studied numerically using the coupled criterion and matched asymptotic expansions. A reference isotropic model material is defined with elastic and fracture properties close to nacre-like alumina. The influence of elastic properties, fracture properties, and anisotropy orientation on crack initiation angle and crack initiation force is evaluated. The objective of this work is to determine if nacre-like alumina resistance to crack initiation could be improved by tuning its elastic or fracture properties. Toughness anisotropy significantly affects the crack initiation angle without significantly influencing the crack initiation force, provided that the anisotropy remains low. Conversely, elastic anisotropy can significantly increase the crack initiation force but has a limited effect on the crack initiation angle. Nacre-like alumina already exhibits a near-optimal toughness anisotropy. However, increasing the elastic anisotropy in nacre-like alumina could significantly improve its crack initiation resistance.

利用耦合准则和匹配渐近展开,对弹性和韧性各向异性对 V 型缺口试样裂纹萌生的影响进行了数值研究。定义了一种各向同性参考模型材料,其弹性和断裂特性接近于珍珠状氧化铝。评估了弹性特性、断裂特性和各向异性取向对裂纹起始角和裂纹起始力的影响。这项工作的目的是确定是否可以通过调整类珍珠质氧化铝的弹性或断裂特性来提高其抗裂纹起始性。只要各向异性保持在较低水平,韧性各向异性会显著影响裂纹起始角,而不会明显影响裂纹起始力。相反,弹性各向异性可显著增加裂纹萌发力,但对裂纹萌发角的影响有限。珍珠质氧化铝已经表现出接近最佳的韧性各向异性。然而,增加类珍珠质氧化铝的弹性各向异性可显著提高其抗裂纹萌发能力。


Mechanisms and micromechanics of intergranular ductile fracture

C. Sénac

doi:10.1016/j.ijsolstr.2024.112951

晶间韧性断裂的机理和微观力学

The process of void nucleation, growth, and coalescence is among the dominant ductile failure modes in metallic alloys and can be transgranular as well as intergranular. In the latter case, the phenomenon of void growth and coalescence happens at grain boundaries due to intense intergranular plastic flow and is associated with fracture surfaces displaying intergranular facets covered in fine dimples. The present review gives a comprehensive summary of intergranular ductile fracture mechanisms based on available experimental evidence, allowing to distinguish precisely this failure mode from other related processes. Moreover, the metallic alloys of industrial significance that can exhibit intergranular ductile fracture are carefully outlined. Then, in order to lay bridges between material science and fracture micromechanics, an overview of the current development of the local approach to fracture applied to grain boundary ductile failure is presented. Emphasis is placed on the accounting of crystallographic effects. Finally, prospects for progress in intergranular ductile fracture modeling and simulation are detailed. In particular, it is foreseen that conflicting trends seen on fracture toughness could be reconciled thanks to physically-based approaches.

空洞的成核、生长和凝聚过程是金属合金中最主要的韧性破坏模式之一,可以是跨晶粒破坏,也可以是晶间破坏。在后一种情况下,由于强烈的晶间塑性流动,空洞生长和凝聚现象发生在晶粒边界,并与断裂表面上覆盖着细小凹痕的晶间面有关。本综述根据现有的实验证据,全面总结了晶间韧性断裂机制,从而将这种失效模式与其他相关过程精确区分开来。此外,还仔细概述了可出现晶间韧性断裂的工业用金属合金。然后,为了在材料科学和断裂微观力学之间架起桥梁,介绍了应用于晶界韧性断裂的局部断裂法的当前发展概况。重点是晶体学效应的考虑。最后,详细介绍了晶间韧性断裂建模和模拟的发展前景。特别是,由于采用了基于物理的方法,可以预见在断裂韧性方面出现的相互矛盾的趋势将得到调和。


Artificial neural network-based homogenization model for predicting multiscale thermo-mechanical properties of woven composites

Menglei Li, Bing Wang, Jiqiang Hu, Gao Li, Peng Ding, Chunming Ji, Bing Wang

doi:10.1016/j.ijsolstr.2024.112965

基于人工神经网络的均质化模型,用于预测编织复合材料的多尺度热机械特性

In this study, we propose an efficient homogenization model based on the fast Fourier transform (FFT) method and artificial neural network (ANN) models to predict the multiscale thermo-mechanical properties of woven composites. We innovatively use the FFT-Plate method to solve the periodic Lippmann–Schwinger equations for thermoelastic problems of heterogeneous plates. We utilize the classical FFT method to determine the homogenized properties of microscale representative volume element (RVE) models and the FFT-Plate method to compute the homogenized properties of mesoscale RVE models for woven composites. In addition, the number of ANN models is determined based on the Pearson correlation coefficient, the Bayesian optimization (BO) algorithm is introduced to optimize the hyperparameters of the ANN models, and the Shapley Additive exPlanations (SHAP) method provides insights into the interpretability of these models. The homogenization model takes into account the material properties of micro constituents, meso-structural parameters, and void defects in woven composites. To evaluate the accuracy of the homogenization model, the predicted uncertainties of unidirectional composites and the stochastic mechanical properties of plain woven composites are compared with experimental results, and the error of the homogenization model is less than 5 %, demonstrating its robustness and reliability.

在本研究中,我们提出了一种基于快速傅立叶变换(FFT)方法和人工神经网络(ANN)模型的高效均质化模型,用于预测编织复合材料的多尺度热机械性能。我们创新性地使用 FFT-Plate 方法来求解异质板材热弹性问题的周期性 Lippmann-Schwinger 方程。我们利用经典的 FFT 方法确定微尺度代表体积元素(RVE)模型的均质特性,并利用 FFT-Plate 方法计算编织复合材料中尺度 RVE 模型的均质特性。此外,还根据皮尔逊相关系数确定了 ANN 模型的数量,引入了贝叶斯优化(BO)算法来优化 ANN 模型的超参数,并通过 Shapley Additive exPlanations(SHAP)方法深入了解了这些模型的可解释性。均质化模型考虑了编织复合材料中微观成分的材料特性、中观结构参数和空隙缺陷。为了评估均质化模型的准确性,将单向复合材料的预测不确定性和普通编织复合材料的随机力学性能与实验结果进行了比较,均质化模型的误差小于 5%,证明了其稳健性和可靠性。


Journal of the Mechanics and Physics of Solids

Minimal actuation and control of a soft hydrogel swimmer from flutter instability

Ariel Surya Boiardi, Giovanni Noselli

doi:10.1016/j.jmps.2024.105753

从扑腾不稳定性中实现对软水凝胶游泳器的最小驱动和控制

Micro-organisms propel themselves in viscous environments by the periodic, nonreciprocal beating of slender appendages known as flagella. Active materials have been widely exploited to mimic this form of locomotion. However, the realization of such coordinated beating in biomimetic flagella requires complex actuation modulated in space and time. We prove through experiments on polyelectrolyte hydrogel samples that directed undulatory locomotion of a soft robotic swimmer can be achieved by untethered actuation from a uniform and static electric field. A minimal mathematical model is sufficient to reproduce, and thus explain, the observed behavior. The periodic beating of the swimming hydrogel robot emerges from flutter instability thanks to the interplay between its active and passive reconfigurations in the viscous environment. Interestingly, the flutter-driven soft robot exhibits a form of electrotaxis whereby its swimming trajectory can be controlled by simply reorienting the electric field. Our findings trace the route for the embodiment of mechanical intelligence in soft robotic systems by the exploitation of flutter instability to achieve complex functional responses to simple stimuli. While the experimental study is conducted on millimeter-scale hydrogel swimmers, the design principle we introduce requires simple geometry and is hence amenable for miniaturization via micro-fabrication techniques. We believe it may also be transferred to a wider class of soft active materials.

微生物通过被称为鞭毛的细长附肢的周期性、非互惠性跳动,在粘性环境中推动自身前进。活性材料已被广泛用于模仿这种运动形式。然而,要在仿生鞭毛中实现这种协调跳动,需要在空间和时间上进行复杂的驱动调制。我们通过在聚电解质水凝胶样品上的实验证明,软机器人游动器的定向起伏运动可以通过均匀和静态电场的无约束驱动来实现。一个最基本的数学模型就足以再现并解释观察到的行为。由于水凝胶游泳机器人在粘性环境中的主动和被动重新配置之间的相互作用,其周期性跳动产生于扑动不稳定性。有趣的是,扑腾驱动的软机器人表现出一种电共振,只需调整电场方向就能控制其游泳轨迹。我们的发现为在软机器人系统中体现机械智能指明了方向,即利用扑动不稳定性实现对简单刺 激的复杂功能反应。虽然实验研究是在毫米级的水凝胶游泳器上进行的,但我们介绍的设计原理只需要简单的几何形状,因此可以通过微加工技术实现微型化。我们相信,它还可以应用于更广泛的软活性材料。


A multiscale mechanics model for elastic properties of densified wood

Rui Song, Feng Deng, Xu Liang, Jianwei Song, Shengping Shen, Teng Li

doi:10.1016/j.jmps.2024.105761

致密木材弹性特性的多尺度力学模型

We introduce a multiscale mechanics model for analyzing the elastic properties of super-strong densified wood (DW). Our model incorporates microstructural features such as microfibril angle and densification ratio, along with chemical parameters including degree of polymerization, crystallinity, and density of hydrogen bonds. At the nanoscale and microscale, the elastic properties of cellulose nanofibril and cell wall layers are derived analytically using the mechanics of composite materials. Finite element simulations based on representative volume elements are conducted at the mesoscale to obtain homogenized effective elastic properties at the macroscale. Our quantitative investigations validate that microstructural changes and alterations in chemical components significantly enhance DW's mechanical performance. Densification and chemical changes, especially increased cellulose content and reduced lignin, emerge as vital mechanisms for strengthening DW. The model's insights offer valuable guidance for optimizing the two-step preparation process of DW to achieve superior mechanical performance. Additionally, the versatility of the model allows for exploring the influence of cell dimensions and potential applications in designing bioinspired materials.

我们介绍了一种多尺度力学模型,用于分析超强致密化木材(DW)的弹性特性。我们的模型结合了微观结构特征,如微纤维角度和致密化比率,以及化学参数,包括聚合度、结晶度和氢键密度。在纳米和微观尺度上,纤维素纳米纤维和细胞壁层的弹性特性是利用复合材料力学分析得出的。在中观尺度上,基于代表性体积元素进行有限元模拟,以获得宏观尺度上的均质化有效弹性特性。我们的定量研究验证了微观结构的变化和化学成分的改变能显著提高 DW 的机械性能。致密化和化学变化,尤其是纤维素含量的增加和木质素的减少,成为强化 DW 的重要机制。该模型的见解为优化二维纤维素的两步制备过程以实现卓越的机械性能提供了宝贵的指导。此外,该模型的多功能性还有助于探索细胞尺寸的影响以及在设计生物启发材料方面的潜在应用。


Mechanics of Materials

Investigation, validation and implementation of the p-alpha equation of state for concrete media simulation

V.R. Feldgun, D.Z. Yankelevsky, Y.S. Karinski

doi:10.1016/j.mechmat.2024.105083

用于混凝土介质模拟的 p-α 状态方程的研究、验证和实施

Concrete is the most common material in the construction industry and almost the only material used for building security and protective structures. Such structures are intended to withstand extremely high blast and impact loading. One of the key mechanical properties of materials subjected to such extreme loading is the relationship between the hydrostatic pressure and the volumetric strain, which is known as the equation of state (EOS). In porous materials, this relationship is substantially inelastic due to the closure and collapse of pores. Commonly the EOS is obtained experimentally. Implementation of the experimental EOS curves in analytical and numerical solutions for different applications requires approximate simplified expressions for these curves. One of the most common approximations for describing the nonlinear compression of porous media is the p-alpha EOS. The present paper reviews the p-alpha EOS approximations appearing in the literature and discusses controversial issues concerning the full compaction pressure. New p-alpha EOS approximations are presented for a variety of experimental hydrostatic test results conducted by the authors for different concrete compositions with equal uniaxial compressive strength. An extended investigation is dedicated to the formulation of the p-alpha approximation in the case of limited available data, and a "blind prediction" of the pi-alpha EOS is proposed.To demonstrate the implementation of the derived p-alpha EOS, an extended example is presented, where the quasi-static cavity expansion problem in a concrete medium that is characterized by the p-alpha EOS is worked out.

混凝土是建筑业中最常见的材料,也几乎是用于建造安全防护结构的唯一材料。此类结构需要承受极高的爆炸和冲击载荷。承受这种极端荷载的材料的关键机械特性之一是静水压力与体积应变之间的关系,即所谓的状态方程(EOS)。在多孔材料中,由于孔隙的闭合和塌陷,这种关系实质上是非弹性的。EOS 通常是通过实验获得的。要在不同应用的分析和数值解决方案中使用实验 EOS 曲线,需要对这些曲线进行近似简化表达。p-alpha EOS 是描述多孔介质非线性压缩的最常用近似值之一。本文回顾了文献中出现的 p-α EOS 近似值,并讨论了有关全压实压力的争议问题。本文针对作者对具有相同单轴抗压强度的不同混凝土成分进行的各种水压试验结果提出了新α-EOS 近似值。在可用数据有限的情况下,对 p-α 近似值的表述进行了扩展研究,并提出了 pi-α EOS 的 "盲预测 "方法。为了演示推导出的 p-α EOS 的实施,介绍了一个扩展示例,在该示例中研究了以 p-α EOS 为特征的混凝土介质中的准静态空腔膨胀问题。


International Journal of Plasticity

Revealing mechanism of ductility improvement of titanium thin sheet under normal stress at mesoscale from perspective of microstructure evolution

Haiyang Wang, Gang Chen, Peng Zhang, Chuanjie Wang

doi:10.1016/j.ijplas.2024.104055

从微观结构演化的角度揭示钛薄板在中尺度法向应力作用下延展性改善的机理

Improving the formability of sheet metal is a constant challenge in microforming. In this study, applying normal stresses to the specimen surface is found to be an effective method for improving the ductility of pure titanium sheets. This case only occurs when the normal stress is higher than a critical value. By characterizing the microstructure, it is found that the normal stress induces a change in the deformation mechanism, which improves the work-hardening rate and the capacity for homogeneous deformation. The plastic deformation mechanism of pure titanium thin sheets undergoes a transformation from exclusively slip-based to a multi-mechanistic mode that couples slip, twinning, and FCC phase transformation. Normal stresses exacerbate the deformation of surface grains and inhibit surface roughening. Moreover, normal stress activates deformation twins and FCC phase transformation by increasing the Schmid factor of the associated twin/slip systems. FCC phases and deformation twins contribute to enhancing the work-hardening rate through mechanisms such as the dynamic Hall-Petch effect, reorientation texture hardening, and dislocation substructure strengthening. Moreover, they enhance the material's ductility by providing additional deformation modes to accommodate strain. By virtue of the coordinated action of various deformation mechanisms, a more uniform distribution of thickness strain is achieved. It delays onset of plastic instability and enhances the formability of thin sheets. Considering the changes in dislocation density induced by different microstructures, a modified model is constructed. Based on the dislocation density and the surface layer model, this model predicts the flow stress size effect, as well as changes in flow stress and work hardening rate induced by normal stress due to microstructure transformation. This work provides a complete understanding of the mechanical property response and microstructure evolution under normal stress. It also gives a feasible solution for improving the formability of titanium thin sheet in microforming.

提高金属板材的成形性是微成形领域的一项长期挑战。本研究发现,在试样表面施加法向应力是提高纯钛板延展性的有效方法。只有当法向应力高于临界值时,才会出现这种情况。通过表征微观结构发现,法向应力会引起变形机制的改变,从而提高加工硬化率和均匀变形能力。纯钛薄板的塑性变形机制从完全基于滑移的模式转变为滑移、孪晶和 FCC 相变耦合的多机制模式。法向应力会加剧表面晶粒的变形,抑制表面粗化。此外,法向应力通过增加相关孪晶/滑移系统的施密特因子,激活变形孪晶和催化裂化相变。FCC 相和变形孪晶通过动态霍尔-佩奇效应、重新定向纹理硬化和位错亚结构强化等机制,有助于提高加工硬化率。此外,它们还通过提供额外的变形模式来适应应变,从而增强了材料的延展性。在各种变形机制的协调作用下,厚度应变的分布更加均匀。这可以延迟塑性不稳定性的出现,并提高薄板的成型性。考虑到不同微结构引起的位错密度变化,我们构建了一个修正模型。基于位错密度和表面层模型,该模型预测了流动应力大小效应,以及由于微观结构转变引起的流动应力和法向应力引起的加工硬化率的变化。这项工作使人们对法向应力下的机械性能响应和微观结构演变有了全面的了解。它还为改善钛薄板在微成型中的成型性提供了可行的解决方案。


Thin-Walled Structures

A quadruple physics coupling model for vibro-acoustic analysis of heavy fluid-loaded porous FGMEE plates via partition collocation points method

Xinxin Wang, Tiangui Ye, Guoyong Jin, Yukun Chen, Zhigang Liu

doi:10.1016/j.tws.2024.112181

通过分区配位点法建立重流体负载多孔 FGMEE 板振动声学分析的四重物理耦合模型

Functionally graded magneto-electro-elastic (FGMEE) materials advance industrial intelligence. Understanding the vibro-acoustic behavior of such structures is crucial for designing and optimizing smart structures. Therefore, considering the pores generated in material manufacturing, this paper establishes a magneto-electro-elastic-acoustic coupling model for underwater vibration and sound radiation of porous FGMEE plates for the first time. Using an improved Voigt formula to characterize the material properties under four pore distributions. Different constraints are quantified as boundary potential energy via virtual springs. The vibrational framework is supported by the first-order shear deformation theory together with MEE constitutive correlations. When taking into account the acoustic pressure loading effect, a partition collocation points method (PCPM) is developed to achieve rapid formulation of the vibro-acoustic coupling problem. The PCPM not only circumvents complicated integrals but also effectively addresses the inherent singularity issues of the Rayleigh integral. Chebyshev polynomials are selected as the spectral functions, and the final characteristic equation is derived by the Rayleigh-Ritz method. Numerical instances validate the feasibility of the solution approach, and the vibro-acoustic analysis of heavy fluid-loaded porous FGMEE plates is conducted comprehensively. It is believed that this study may provide theoretical and data support for subsequent research in this domain.

功能分级磁电弹性(FGMEE)材料推动了工业智能化的发展。了解这类结构的振动声学行为对于设计和优化智能结构至关重要。因此,考虑到材料制造过程中产生的孔隙,本文首次建立了多孔 FGMEE 板水下振动和声辐射的磁弹声耦合模型。利用改进的 Voigt 公式表征了四种孔隙分布下的材料特性。不同的约束条件通过虚拟弹簧量化为边界势能。振动框架由一阶剪切变形理论和 MEE 构成相关性提供支持。在考虑声压加载效应时,开发了一种分区配位点法(PCPM),以实现振动-声耦合问题的快速表述。PCPM 不仅规避了复杂的积分,还有效解决了瑞利积分固有的奇异性问题。选择切比雪夫多项式作为谱函数,并通过 Rayleigh-Ritz 方法推导出最终特征方程。数值实例验证了求解方法的可行性,并对重流体负载多孔 FGMEE 板进行了全面的振动声学分析。相信本研究可为该领域的后续研究提供理论和数据支持。


Legendre-Ritz solutions for vibration characteristics of three-dimensional double-layer lattice truss sandwich plates

Shuo Meng, Qingshan Wang, Rui Zhong, Bin Qin

doi:10.1016/j.tws.2024.112185

三维双层格构桁架夹层板振动特性的 Legendre-Ritz 解决方案

In this paper, Legendre-Ritz solutions for vibration characteristics of double-layer lattice truss sandwich plates are proposed based on three-dimensional (3-D) elasticity theory. Double-layer lattice truss sandwich plates consist of three face sheets and two cores. The face sheets are composed of fiber-reinforced composites and the cores are composed of pyramidal lattice trusses made of isotropic materials. The pyramidal lattice core is equated to a homogeneous plate according to equivalence principle. Based on 3-D elasticity theory and pseudo excitation method (PEM), each layer's energy expressions of double-layer lattice truss sandwich plates are constructed. After that, Legendre polynomials are adopted to describe displacement components in length, width and thickness directions. On this basis, the Rayleigh-Ritz method is used to solve energy functions to obtain motion equations of double-layer lattice truss sandwich plates. The accuracy and validity of the present method are corroborated by comparisons with references and finite element method (FEM). Additionally, in order to find out effects of relevant parameters on dynamical characteristics of double-layer lattice truss sandwich plates, parametric studies are carried out by means of some numerical examples.

本文基于三维(3-D)弹性理论,提出了双层格构桁架夹层板振动特性的 Legendre-Ritz 解决方案。双层格构桁架夹层板由三块面板和两块芯板组成。面板由纤维增强复合材料组成,芯板由各向同性材料制成的金字塔格构桁架组成。根据等效原理,金字塔晶格核心等同于均质板。基于三维弹性理论和伪激励法(PEM),构建了双层网格桁架夹层板各层的能量表达式。然后,采用 Legendre 多项式来描述长度、宽度和厚度方向上的位移分量。在此基础上,采用雷利-里兹法求解能量函数,从而得到双层格构桁架夹层板的运动方程。通过与参考文献和有限元法(FEM)的比较,证实了本方法的准确性和有效性。此外,为了找出相关参数对双层格构桁架夹层板动力学特性的影响,还通过一些数值实例进行了参数研究。




来源:复合材料力学仿真Composites FEM
ACTMechanicalAdditiveOpticalSystem振动断裂复合材料非线性化学多孔介质建筑裂纹理论材料机器人仿生
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【新文速递】2024年7月6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 2 篇,Mechanics of Materials 1 篇,International Journal of Plasticity 1 篇,Thin-Walled Structures 7 篇International Journal of Solids and StructuresMultiscale simulation of spatially correlated microstructure via a latent space representationReese E. Jones, Craig M. Hamel, Dan Bolintineanu, Kyle Johnson, Robert Buarque de Macedo, Jan Fuhg, Nikolaos Bouklas, Sharlotte Kramerdoi:10.1016/j.ijsolstr.2024.112966通过潜空间表示法对空间相关微观结构进行多尺度模拟When deformation gradients act on the scale of the microstructure of a part due to geometry and loading, spatial correlations and finite-size effects in simulation cells cannot be neglected. We propose a multiscale method that accounts for these effects using a variational autoencoder to encode the structure–property map of the stochastic volume elements making up the statistical description of the part. In this paradigm the autoencoder can be used to directly encode the microstructure or, alternatively, its latent space can be sampled to provide likely realizations. 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The validated model is further employed to simulate the multiphysics hot cracking phenomenon in additive manufacturing in the context of both the effective powder-bed model and the powder-resolved model thanks to prior non-isothermal phase-field powder-bed-fusion simulations. 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Experiments on metallic lattices admit the characterization of the linear elastic wave dispersion over a wide range of frequencies, resulting in complete, experimentally-constructed dispersion surfaces in excellent agreement with predictions obtained from finite element-based Bloch wave analysis. While Timoshenko beam theory is shown to be sufficiently accurate for predicting the lowest modes, experiments prove that solid finite elements are required to capture the dispersion relations at higher frequencies as well as when mode coupling occurs. Based on an improved numerical procedure, group velocity maps further highlight the directionality of wave dispersion and allow for the simple identification of bandgaps. In addition to classically studied periodic trusses, we extend the framework to spatially graded structures and demonstrate acoustic rainbow trapping in beam lattices undergoing out-of-plane vibrations. 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CoCrNi medium-entropy alloy, known for its high strength and high ductility, is an ideal candidate for fabricating TPMS-based structures. However, few studies have focused on this topic. This study investigated the compressive mechanical and energy absorption properties of CoCrNi D-sheet TPMS cellular structures fabricated via selective laser melting (SLM). The surface morphology of the fabricated D-sheet TPMS structure was observed through scanning electron microscopy, and the deformation and failure mechanisms of the structure were analyzed by the quasi-static compression test. The results indicated that the SLM-ed CoCrNi D-sheet TPMS structure exhibited stable collapse mechanisms compared to other metal-based TPMS structures. Meanwhile, the energy absorption characteristics of the modified finite element (FE) model agreed well with the experimental results. Furthermore, the impact of the level constant on the energy absorption performance of the D-sheet TPMS structure was investigated using the FE model. Thus, an optimal D-sheet (OD-sheet) TPMS structure with lower density and higher energy absorption capacity was obtained. Additionally, the Gibson–Ashby prediction model was established to aid in selecting CoCrNi OD-sheet TPMS structures with controlled relative densities for energy absorption applications.三周期极小表面(TPMS)被广泛用作细胞结构微结构设计的有效工具。钴铬镍中熵合金以高强度和高延展性著称,是制造基于 TPMS 结构的理想候选材料。然而,很少有研究关注这一主题。本研究调查了通过选择性激光熔化(SLM)制造的钴铬镍 D 片 TPMS 蜂窝结构的压缩机械性能和能量吸收性能。通过扫描电子显微镜观察了制作的 D 片 TPMS 结构的表面形貌,并通过准静态压缩试验分析了结构的变形和失效机理。结果表明,与其他金属基 TPMS 结构相比,SLM-ed CoCrNi D-sheet TPMS 结构具有稳定的崩溃机制。同时,修改后的有限元(FE)模型的能量吸收特性与实验结果非常吻合。此外,还利用有限元模型研究了水平常数对 D 片 TPMS 结构能量吸收性能的影响。因此,得到了一种密度更低、能量吸收能力更强的最佳 D-sheet(OD-sheet)TPMS 结构。此外,还建立了吉布森-阿什比预测模型,以帮助选择具有可控相对密度的钴铬镍 OD 片 TPMS 结构用于能量吸收应用。International Journal of PlasticityA Crystal Plasticity Based Strain Rate Dependent Model across An Ultra-wide RangeXiaochuan Sun, Kecheng Zhou, Chuhao Liu, Xiaodan Zhang, Huamiao Wangdoi:10.1016/j.ijplas.2024.104056基于晶体塑性的超宽范围应变率相关模型Numerous studies have investigated the strain rate sensitive behaviors of materials, consistently reporting enhanced stress values and increased dislocation density with rising strain rates. Behind these phenomena lies the intrinsic nature of dislocation activity. In this context, we introduce an analysis method within a crystal-plasticity (CP) framework, incorporating molecular dynamics insights for a comprehensive range of strain rates (7.5 × 10−5/s to 5 × 107/s). This approach offers a refined understanding of strain rate sensitivity (SRS) behaviors, mainly influenced by dislocation movement laws and strain-rate-dependent saturation of dislocation density. We elucidate the impact of deformation loading conditions on Schmidt factors and active slip systems, which are also crucial for understanding variations in SRS. 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The first step consists of a non-standard continualization accounting for scale effects. Several methods are explored to derive new continuum models, whose dispersive and vibrational behaviors are compared to that of the lattice, considered as a reference. Non-classical models with micro-inertia reveal high accuracy, not presenting physical inconsistencies. The second step follows a FEM spatial discretization of the developed continua, accounting for micro inertia terms in the mass matrix. Finally, the FEM formulation allows the use of element sizes larger (up to four times) than the physical length scale of the lattice system, thus significantly reducing the computational cost while maintaining accuracy and enabling a versatile application to materials, geometries and boundary conditions. The methodology is tested here for a 2D system with displacements in the plane, but can be extended to other lattice typologies as well.本研究提出了一种新方法,通过两步法对弹性晶格系统进行建模,从而能够可靠地捕捉其动态行为,且计算成本低于对晶格的显式建模。第一步是考虑尺度效应的非标准连续化。我们探索了几种方法来推导新的连续模型,并将其色散和振动行为与作为参考的晶格的色散和振动行为进行比较。具有微惯性的非经典模型显示出很高的精确度,不会出现物理上的不一致性。第二步是对已开发的连续体进行有限元空间离散化,并考虑质量矩阵中的微惯性项。最后,有限元公式允许使用比晶格系统物理长度尺度更大(最多四倍)的元素尺寸,从而在保持精度的同时显著降低了计算成本,并使其能够广泛应用于材料、几何形状和边界条件。本文对平面位移的二维系统进行了测试,但也可扩展到其他晶格类型。Extending the Finite Area Method for enhanced simulation of deformable membranes and its application to extrusion blow mouldingWagner de Campos Galuppo, Pedro Santana, Francisco Alves, João Miguel Nóbregadoi:10.1016/j.tws.2024.112184扩展有限面积法以增强对可变形膜的模拟及其在挤压吹塑成型中的应用This paper investigates the mechanics of the Extrusion Blow Moulding (EBM) process, focusing on the clamp and inflation phases. The simulation framework employed in this study has been developed using OpenFOAM ® and extended the available Finite Area Method with a vertex-centred approach. This cutting-edge developments integrated a corotational formulation with a quasi-static approximation. The computational code and algorithm are verified and validated through comparisons between analytical solutions, experimental measurements and simulation results, ensuring the accuracy and reliability of the proposed approach. The implemented code is verified by checking fundamental principles of hyperelastic materials behaviour, demonstrated through equibiaxial deformation of spherical balloons. The use of neo-Hookean and Mooney–Rivlin material models provides crucial insights into material responses under different inflation conditions. The studies begin employing a conceptual mould within the EBM process that allows examining the effects of mould clamping on parison deformation. Then the study extends to analysing a real bottle manufactured via EBM, employing Stereolithography (STL) digitization and thickness mapping to quantify the material distribution. The simulation results closely replicates experimental observations, capturing the inherent non-linearity of these process stages, including large deformations and displacements, hyperelasticity and parison-mould contacts. This interdisciplinary research enhances understanding of the EBM process phases and analogous processes, providing valuable insights for plastic manufacturing. It improves the design process for meeting specific requirements and offers guidelines to avoid potential failures. The findings underscore the importance of such studies in advancing sustainable and efficient plastic manufacturing practices, with applications ranging from inflatable structures to EBM processes.本文研究了挤压吹塑成型(EBM)工艺的力学原理,重点是夹模和充气阶段。本研究中采用的模拟框架是利用 OpenFOAM ® 开发的,并以顶点为中心扩展了现有的有限区域法。这一尖端技术的发展将矢量计算与准静态近似结合在一起。计算代码和算法通过分析解决方案、实验测量和模拟结果之间的比较进行了验证和确认,确保了所建议方法的准确性和可靠性。通过球形气球的等轴变形,检查超弹性材料行为的基本原理,验证了所实施的代码。通过使用新胡克恩和穆尼-里夫林材料模型,可以深入了解材料在不同充气条件下的反应。研究首先在 EBM 过程中使用概念模具,以检查模具夹紧对型坯变形的影响。然后,研究扩展到分析通过 EBM 制造的真实瓶子,采用立体光刻(STL)数字化和厚度映射来量化材料分布。模拟结果与实验观察结果非常接近,捕捉到了这些工艺阶段固有的非线性,包括大变形和位移、超弹性和型坯与模具接触。这项跨学科研究加深了对 EBM 工艺阶段和类似工艺的理解,为塑料制造提供了宝贵的见解。它改进了满足特定要求的设计过程,并提供了避免潜在故障的指导原则。研究结果强调了此类研究在推进可持续和高效塑料制造实践方面的重要性,其应用范围包括充气结构和 EBM 工艺。Behavior of reinforced CHS T-joints by welding collar plates under loadZhaowei Li, Hongfei Chang, Tenglong Ren, Ziyang Meng, Yichao Yin, Ningtao Liu, Yuner Huang, Junwu Xiadoi:10.1016/j.tws.2024.112187通过焊接领圈板加固的 CHS T 型接头在荷载作用下的行为The paper presents a comprehensive test program on collar plate reinforced CHS T-joints under different preload conditions, in order to investigate the effect of preload and welding thermal on reinforced joints. A total of four specimens, including specimens with and without preload when the collar plates were welded, were tested under brace axial loading. The test results, including welding temperature field, development of strain as well as welding residual deformation during the welding process are measured and presented in this paper. Furthermore, the failure model and compressive strength of the collar plate reinforced T-joints were determined. The test results demonstrated that the localized high temperature and rapid attenuation are the characteristics of the welding temperature field, which instantaneous peak temperature rose to 1808 °C at the local area and attenuated to 600 °C in an elliptic range of about 3.1 cm × 1.7 cm. The failure modes of collar plate reinforced CHS T-joints do not change with preload on the chord and welding thermal. Furthermore, preload on the chord reduces the compressive strength of reinforced joints. The strain distribution and residual deformation are affected by the thermal expansion and cold shrinkage, while the development of the welding temperature field is not affected by the preload. Finally, for compressive strength of CHS T-joints reinforced with collar plate by welding, the applicability of the reduction coefficient due to preload calculated by existing codes was assessed by comparing design values with experimental results. A finite element model by ANSYS, considering the welding heat, was established. Key parameters affecting the strength of the T-joint at the reinforced collar plate under load were identified through parametric study with finite element models. Construction recommendations of welded CHS T-joints are proposed.本文介绍了不同预紧力条件下领圈板加固 CHS T 型接头的综合测试方案,以研究预紧力和焊接热对加固接头的影响。在支撑轴向载荷下,共测试了四个试样,包括领圈板焊接时有预载和无预载的试样。本文测量并展示了测试结果,包括焊接温度场、应变发展以及焊接过程中的焊接残余变形。此外,还确定了领圈板加固 T 型接头的失效模型和抗压强度。试验结果表明,局部高温和快速衰减是焊接温度场的特征,局部区域的瞬时峰值温度升至 1808 ℃,并在约 3.1 cm × 1.7 cm 的椭圆范围内衰减至 600 ℃。领圈板加固 CHS T 型接头的破坏模式并不随弦杆预紧力和焊接热而变化。此外,弦上的预紧力会降低加固接头的抗压强度。应变分布和残余变形受热膨胀和冷缩的影响,而焊接温度场的发展则不受预紧力的影响。最后,通过比较设计值和实验结果,评估了现有规范计算的因预载而降低的系数是否适用于通过焊接用领圈板加固的 CHS T 型接头的抗压强度。通过 ANSYS 建立了一个考虑到焊接热量的有限元模型。通过对有限元模型进行参数化研究,确定了影响加固领圈板 T 型接头在荷载作用下强度的关键参数。提出了焊接 CHS T 型接头的构造建议。Towards accurate prediction of the dynamic behavior and failure mechanisms of three-dimensional braided composites: a multiscale analysis schemeYangxuan Zhu, Chunwang He, Tian Zhao, Ying Lidoi:10.1016/j.tws.2024.112188准确预测三维编织复合材料的动态行为和失效机理:多尺度分析方案In this paper, a dynamic multiscale model is proposed for three-dimensional four-directional (3D4D) braided composites, considering the effects of strain rate and shear enhanced failure mechanism. The strain rate-dependent constitutive models are established for both resin and yarns. The accuracy of the yarn model is validated by comparing the simulated stress-strain curves with the experimental results obtained from the Split Hopkinson Pressure Bar (SHPB) tests with various strain rates. The shear enhancement coefficient of the yarn is determined from the failure envelopes with a discussion of crack propagation angles. The results show that, based on the calculated microscale properties, the mesoscale model accurately predicts both the longitudinal and transverse compressive strain-stress behavior of 3D4D braided composites at different strain rates. A comparative analysis reveals that the shear-enhanced failure model achieves a better prediction compared with other counterparts, such as Hashin-Rotem and Tsai-Wu Models. The proposed dynamic multiscale scheme for 3D braided composites is an efficient and accurate tool to characterize their multiscale features and strain rate-dependent behavior.本文提出了三维四向(3D4D)编织复合材料的动态多尺度模型,考虑了应变率和剪切增强失效机制的影响。为树脂和纱线建立了与应变速率相关的构成模型。通过比较模拟应力-应变曲线和不同应变率下的裂开霍普金森压力棒(SHPB)试验结果,验证了纱线模型的准确性。通过对裂纹扩展角度的讨论,从失效包络线中确定了纱线的剪切增强系数。结果表明,根据计算得出的微观特性,中尺度模型可以准确预测 3D4D 编织复合材料在不同应变速率下的纵向和横向压缩应变应力行为。对比分析表明,与其他同类模型(如 Hashin-Rotem 和 Tsai-Wu 模型)相比,剪切增强失效模型实现了更好的预测效果。针对三维编织复合材料提出的动态多尺度方案是表征其多尺度特征和应变速率相关行为的有效而精确的工具。Experimental behaviour of axially loaded circular high-strength concrete-filled high-strength steel tubular stub columns after exposure to fireYing Li, Faqi Liu, Tao Du, Yanchong Pan, Hua Yang, Yinglong Lidoi:10.1016/j.tws.2024.112189轴向加载的圆形高强度混凝土填充高强度钢管桩柱受火烧后的实验行为The high-strength concrete-filled high-strength steel tubular (HCFHST) column is an innovative type of high-performance steel-concrete composite component, which has a broad prospect for engineering applications. To investigate the axial compressive behaviour of post-fire HCFHST stub columns with circular cross-sections, twenty-five specimens were heated following ISO 834 standard fire and then loaded to failure under axial compression after being cooled. The effects of various heating durations, concrete and steel strength on the temperature distribution, spalling of the steel-concrete interface, post-fire ultimate bearing capacity and axial stiffness were analyzed. The residual ultimate capacity and axial stiffness of HCFHST stub columns experience a pronounced decrease as the heating duration increases. High strength steel has no significant contribution to the enhancement of the post-fire axial stiffness of HCFHST stub columns, and the effect level of high-strength concrete on the failure load of composite columns subjected to different heating durations is similar. Finally, the applicability of relevant equations for the residual compressive capacity of the ordinary strength CFST column to HCFHST stub columns was evaluated. The evaluation results revealed that available methods of conventional strength CFST stub columns cannot obtain accurate post-fire resistance predictions of circular HCFHST stub columns.高强度混凝土填充高强度钢管(HCFHST)柱是一种创新型高性能钢-混凝土复合材料构件,在工程应用中具有广阔的前景。为了研究火灾后圆形截面 HCFHST 短柱的轴向压缩行为,我们按照 ISO 834 标准对 25 个试件进行了火灾加热,冷却后对其进行轴向压缩加载至破坏。分析了各种加热持续时间、混凝土和钢强度对温度分布、钢-混凝土界面剥落、火灾后极限承载力和轴向刚度的影响。随着加热时间的延长,HCFHST 存根柱的残余极限承载力和轴向刚度明显下降。高强度钢对 HCFHST 存根柱火后轴向刚度的增强作用不明显,高强度混凝土对不同加热持续时间下复合材料柱破坏荷载的影响程度相似。最后,评估了普通强度 CFST 柱的残余抗压能力相关公式对 HCFHST 存根柱的适用性。评估结果表明,常规强度 CFST 存根柱的现有方法无法准确预测圆形 HCFHST 存根柱的耐火后性能。Bending-bearing capacity design of transformed triangular corrugated plates with top stringersYanguo Hou, Chenbao Wen, Yanlin Guo, Haojun Sundoi:10.1016/j.tws.2024.112191 带顶梁的变形三角形波纹板的弯曲承载力设计This study investigates the bending-bearing capacity and design method of Transformed Triangular Corrugated Steel Plates (TT-CSPs) with top stringers adopted in trestles subjected to possible pure bending. Elastic buckling load and ultimate strength are derived through theoretical deduction and numerical analysis. Exploration focuses on the impact of boundary conditions, aspect ratio, corrugation density, and top stringers on buckling behavior and ultimate strength. This paper advances a design approach for the bending-bearing capacity of TT-CSPs with top stringers. Findings indicate that the vertical boundaries of TT-CSPs cannot meet the plane assumption and are close to being free-warping. Higher corrugation densities increase structural stiffness and uniformity, while TT-CSP height variations significantly affect stability. Top stringers behave as lateral constraints and undergo significant bending stresses, with their various buckling modes influencing the bending-bearing stability capacity of TT-CSPs.本研究探讨了变形三角形波纹钢板(TT-CSP)的抗弯承载能力和设计方法,该钢板在栈桥中采用了上弦杆,可能会受到纯弯曲的影响。通过理论推导和数值分析得出了弹性屈曲载荷和极限强度。探讨的重点是边界条件、长宽比、波纹密度和上弦对屈曲行为和极限强度的影响。本文提出了一种带有顶弦杆的 TT-CSP 弯曲承载能力设计方法。研究结果表明,TT-CSP 的垂直边界无法满足平面假设,接近于自由弯曲。较高的波纹密度可提高结构刚度和均匀性,而 TT-CSP 高度变化则会严重影响稳定性。顶部弦杆起横向约束作用,承受巨大的弯曲应力,其各种屈曲模式影响着 TT-CSP 的弯曲承载稳定性能力。Dynamic Response of Girder Bridges with Corrugated Steel Webs Subjected to Moving LoadsQiangbo Li, Man Zhoudoi:10.1016/j.tws.2024.112180波形钢腹板梁桥在移动荷载作用下的动态响应Girders with corrugated steel webs (CSWs), replacing traditional concrete webs in prestressed concrete box girders, exhibit a unique dynamic behavior due to the accordion effect and the thinner dimension of CSWs. The study aims to investigate the dynamic response of girder bridges with CSWs under moving loads. Utilizing the Timoshenko beam theory and modal analysis method, the analytical formula for the dynamic response, considering shear deformation and rotational inertia, was developed. The proposed analytical formula was validated through finite element simulation. Employing dimensionless parameters, a parametric analysis was conducted to examine the effects of multi-modes, loading position and shear deformation on the dynamic response of girders with CSWs. The results highlighted the significant influence of the shear parameter αS and the speed parameter SE1 on the magnitude of the impact factor. Precise calculations for deflection and bending moment only require consideration of low-order modes, whereas accurate estimation of shear force requires attention to higher-order modes. In particular, a high-frequency resonance phenomenon is identified when the speed parameter SE1 and the shear parameter αS conformed to the formula “πSE1αS = 1”. The suggested impact factor formulas for midpoint deflection, midpoint bending moment and end shear force have been develop and categorized into three groups based on the magnitude of the shear parameter αS.波形钢腹板(CSW)梁取代了预应力混凝土箱梁中传统的混凝土腹板,由于波形钢腹板的风琴效应和较薄的尺寸,CSW 表现出独特的动态特性。本研究旨在探讨采用 CSW 的梁桥在移动荷载作用下的动态响应。利用季莫申科梁理论和模态分析方法,考虑剪切变形和转动惯量,建立了动态响应分析公式。通过有限元模拟对所提出的分析公式进行了验证。采用无量纲参数,进行了参数分析,以研究多模式、加载位置和剪切变形对带有 CSW 的大梁动态响应的影响。结果表明,剪切参数 αS 和速度参数 SE1 对影响因子的大小有显著影响。挠度和弯矩的精确计算只需要考虑低阶模态,而剪力的精确估算则需要关注高阶模态。特别是,当速度参数 SE1 和剪切参数 αS 符合公式 "πSE1αS=1 "时,就会出现高频共振现象。根据剪力参数 αS 的大小,中点挠度、中点弯矩和端面剪力的影响系数公式被分为三组。来源:复合材料力学仿真Composites FEM

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