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【新文速递】2024年5月22日固体力学SCI期刊最新文章

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今日更新:Journal of the Mechanics and Physics of Solids 2 篇,International Journal of Plasticity 1 篇,Thin-Walled Structures 8 篇

Journal of the Mechanics and Physics of Solids

Energy transmission through and reflection from a layer of random composite

J.R. Willis

doi:10.1016/j.jmps.2024.105689

能量通过和反射一层随机复合材料

An approximate solution to the title problem for a scalar model elastic medium is obtained via a variational formulation. The layer of random composite is a mixture of two materials both of which have the same elastic modulus but different densities while the adjoining homogeneous half-spaces may have any moduli and densities. No information on the composite is assumed, other than statistical uniformity with the one- and two-point probabilities assigned. With the additional assumption of an exponential two-point correlation function, the composite supports exactly two mean plane waves and the solution is correspondingly explicit. Particular attention is paid to the total fluxes of energy. The system is excited by a plane harmonic wave incident from the lower half-space. All of the disturbance so generated is random and can be split into a mean disturbance (which is independent of the sample of the random composite) plus a disturbance whose mean is zero. Both contribute to the mean flux of energy, which conforms to the requirement of conservation of energy, both exactly and in the variational approximation. The entire solution is studied without any approximation other than that in the variational formulation.

通过变分公式,得到了标量模型弹性介质标题问题的近似解。随机复合材料层是弹性模量相同但密度不同的两种材料的混合物,而相邻的均匀半空间可以具有任意模量和密度。除了给定的一点和两点概率的统计一致性外,不假设有关该组合的任何信息。通过对指数两点相关函数的附加假设,该复合结构恰好支持两个平均平面波,其解相应显式。特别注意的是总能量通量。系统由下半空间入射的平面谐波激发。这样产生的所有干扰都是随机的,可以分成一个平均干扰(与随机组合的样本无关)加上一个平均值为零的干扰。两者都有助于平均能量通量,这符合能量守恒的要求,无论是在变分近似中还是在变分近似中。研究整个解时,除了变分公式外,没有任何近似。


Willis dynamic homogenization method for acoustic metamaterials based on multiple scattering theory

Zhanyu Li, Peixin Han, Gengkai Hu

doi:10.1016/j.jmps.2024.105692

基于多重散射理论的声学超材料Willis动态均匀化方法

This paper presents a spatial dispersive Willis dynamic homogenization method for acoustic metamaterials based on multiple scattering theory, which is valid for each physical dimension – 1D, 2D and 3D, and valid for arbitrary inhomogeneities/scatterers – passive or active. The homogenization can be viewed as the monopole and dipole truncation of multiple scattering theory. With the help of layer-doubling scheme, both propagating and evanescent waves can be characterized by the homogenization theory. Further, besides effective field, the theory also considers inner field (often neglected by traditional homogenizations), making it possible to study interface problems with a higher precision than traditional methods. To validate the homogenization theory, a two dimensional acoustic metamaterial composed of a square lattice of C-shape resonators is carefully studied as an application. By the proposed method, we can predict not only effective properties of bulk materials, including real and complex band structures, but also properties of interfaces, including transmission/reflection properties of a layer and dispersion of interface waves. An experiment of interface waves supported by the metamaterials is also conducted, and the results of experiments, simulations and homogenization are all in good agreement. Interestingly, two essentially different evanescent modes of the interface wave are observed in the experiment, and they can be distinguished by the proposed homogenization method, but are undistinguishable via traditional homogenizations. Finally, a detailed discussion on the limitations and some opening questions of the homogenization theory is presented. And the physical restrictions for the case of a reciprocal, passive and lossless material are additionally given and discussed. Our method paves the way for designing Willis’ type metamaterials and further realizing more novel acoustic wave-control functions.

本文提出了一种基于多重散射理论的声学超材料空间色散Willis动态均匀化方法,该方法适用于一维、二维和三维物理维度,适用于任意非均匀性/散射体(被动或主动)。均匀化可以看作是多重散射理论的单极子和偶极子截断。在双层方案的帮助下,传播波和倏逝波都可以用均匀化理论来表征。此外,除了有效场之外,该理论还考虑了内场(通常被传统的均质化方法所忽略),使得该理论能够以比传统方法更高的精度研究界面问题。为了验证均匀化理论,本文研究了一种由c形谐振器的方形晶格组成的二维声学超材料的应用。通过该方法,我们不仅可以预测块状材料的有效性质,包括真实带结构和复杂带结构,还可以预测界面性质,包括层的透射/反射性质和界面波的色散。并进行了超材料支撑界面波的实验,实验结果、模拟结果和均质化结果吻合较好。有趣的是,在实验中观察到两种本质上不同的界面波的消失模式,它们可以通过所提出的均匀化方法进行区分,而通过传统的均匀化方法则无法区分。最后,详细讨论了均质化理论的局限性和一些开放性问题。另外给出并讨论了互易、被动和无损材料的物理限制。我们的方法为设计威利斯型超材料和进一步实现更多新颖的声波控制功能铺平了道路。


International Journal of Plasticity

Calculating the grain size effect during strain hardening through a probabilistic analysis of the mean slip distance in polycrystals.

Rafael Schouwenaars

doi:10.1016/j.ijplas.2024.104012

通过多晶平均滑移距离的概率分析计算应变硬化过程中的晶粒尺寸效应。

Grain refinement is an important mechanism to produce stronger alloys. Strain hardening is an essential phenomenon in metal forming processes. The interaction between grain size and strain hardening is evident: a decrease in grain size (dg) causes an increase in ultimate tensile strength but a decrease in uniform elongation. The Kocks-Mecking (KM) model for strain hardening is based on the relationship between shear strain and the path length for dislocation slip. It provides good general estimates for stress-strain curves, and empirical modifications have been made to include dg. Here, the empirical approach is substituted by theoretical probability calculations, accounting for the fact that the grain size imposes a bound on the mean slip distance, while strain compatibility defines a relationship between grain boundary-dislocation interaction and bulk storage and annihilation. The resulting differential only uses the two parameters inherent to KM. Fitting to published tensile curves for Al, Cu, and Ni produces excellent results. The fitting parameters allow to predict the tensile strength as a function of dg to good approximation, for dg > 1μm. Below this limit, fundamental changes in dislocation statistics impose the activation of grain boundary dislocation sources and may induce dislocation density gradients, which seem to determine the flow stress in the sub-μm range.

晶粒细化是生产强度更高的合金的重要机制。应变硬化是金属成型过程中的一个基本现象。晶粒大小与应变硬化之间的相互作用是显而易见的:晶粒大小(dg)的减小会导致极限抗拉强度的增加,但均匀伸长率却会减小。应变硬化的 Kocks-Mecking (KM) 模型基于剪切应变与位错滑移路径长度之间的关系。该模型为应力-应变曲线提供了良好的一般估计,并根据经验进行了修改,将 dg 包括在内。在这里,理论概率计算取代了经验方法,并考虑到晶粒尺寸对平均滑移距离施加了约束,而应变相容性定义了晶界-位错相互作用与块体存储和湮灭之间的关系。由此产生的差分只使用 KM 固有的两个参数。对已公布的铝、铜和镍的拉伸曲线进行拟合,结果非常好。在 dg > 1μm 的情况下,拟合参数可以很好地近似预测抗拉强度与 dg 的函数关系。在此极限以下,位错统计的基本变化会导致晶界位错源的激活,并可能引起位错密度梯度,这似乎决定了亚微米范围内的流动应力。


Thin-Walled Structures

Vibration Analysis of Graphene-Reinforced Porous Aluminum-Based Variable-Walled Thickness Sandwich Joined Conical-Conical Panel with Elastic Boundary Conditions Using Differential Quadrature Method

H. Li, W. Zhang, Y.F. Zhang

doi:10.1016/j.tws.2024.112016

用微分正交法分析弹性边界条件下石墨烯增强多孔铝基变壁厚夹层连接锥形-锥形板的振动

In this paper, a unified solution is proposed to investigate the vibration characteristics of the variable-walled thickness graphene-reinforced porous aluminum-based (GRPA) sandwich joined conical-conical panel (JCCP) with the arbitrary elastic support boundary conditions by using the differential quadrature method (DQM). The two surfaces of the sandwich JCCP are made of metallic aluminum and the central core layer is the GRPA. The core thickness of each conical plate varies linearly with its generatrix. Three types of the graphene distributions and two types of porosity distributions are considered along the core thickness direction. Based on the first-order shear deformation theory (FSDT), von-Karman strain displacement relationship, constitutive relationship and Hamiltonian principle, the partial differential governing equations of motion are obtained for the variable wall thickness GRPA sandwich JCCP. Using the DQM, the dynamic equation is discretized into the ordinary differential equation. The matrix of the characteristic equation is analyzed to solve the frequencies and mode shapes of the variable wall thickness GRPA sandwich JCCP. The effects of the spring stiffness, boundary conditions, graphene distributions, porosity distributions and geometric parameters on the vibration properties are studied for the variable wall thickness GRPA sandwich JCCP with two interesting elastic supported boundary conditions. At the same time, this article provides a useful approach for studying the arbitrary boundary coupled plate and shell structures with the variable wall thickness.

本文采用微分正交法(DQM)对任意弹性支承边界条件下变壁厚石墨烯增强多孔铝基(GRPA)夹层连接锥形-锥形板(JCCP)的振动特性进行了统一求解。夹层JCCP的两个表面由金属铝制成,中央芯层为GRPA。每个锥形板的芯厚随其母线呈线性变化。沿岩心厚度方向考虑了三种类型的石墨烯分布和两种类型的孔隙度分布。基于一阶剪切变形理论(FSDT)、von-Karman应变位移关系、本构关系和哈密顿原理,得到变壁厚GRPA夹层JCCP的运动偏微分控制方程。利用DQM将动力学方程离散为常微分方程。分析了变壁厚GRPA夹层JCCP的特性方程矩阵,求解了变壁厚GRPA夹层JCCP的频率和振型。研究了弹性支承边界条件下变壁厚GRPA夹层JCCP的弹性刚度、边界条件、石墨烯分布、孔隙率分布和几何参数对其振动性能的影响。同时,本文也为研究变壁厚板壳结构的任意边界耦合提供了一种有用的方法。


Fold defects mechanism of aluminum alloy thin-walled stiffened cylinders during flow forming

Yehui Meng, Zhongqi Yu, Yixi Zhao

doi:10.1016/j.tws.2024.112018

铝合金薄壁加筋汽缸流动成形时褶皱缺陷机理

Flow forming is an advanced technology for manufacturing integrally thin-walled cylinders with orthometric stiffeners (longitudinal stiffeners (LSs) and transverse stiffeners (TSs)), and fold is a typical defect in this process. To understand the forming mechanism of fold defects, a flow forming finite element (FE) model of a representative cylinder with orthometric stiffeners was established, based on physical experiments. Meanwhile, the influence of geometry and process parameters on fold defects was investigated. In order to eliminate fold defects, the influence of sensitive parameter coupling on fold defects was investigated. It was found that the gap between the stiffener and groove wall in the flow forming process is the primary factor for the formation of fold defects, which is larger at the cross-region than that at TS and LS, and forms a surface pit during the subsequent forming process. Finally, the surface pit develops into the fold defect under the compression of material circumferential flow. Parametric analysis shows that the roller attack angle, groove corner radius and rotation trajectory of roller are sensitive to the development of fold defects. By coupling any two sensitive parameters, fold defects can be further weakened. By utilizing all three of them simultaneously, it is possible to completely eliminate fold defects. The results provide methods and guidance for improving the quality of aluminum alloy cylinders with orthometric stiffeners during flow forming.

流动成形是制造具有正交加强筋(纵向加强筋和横向加强筋)的整体薄壁圆柱体的先进工艺,而褶皱是该工艺的典型缺陷。为了解褶皱缺陷的形成机理,在物理实验的基础上,建立了具有代表性的带正交加强筋圆柱的流动成形有限元模型。同时,研究了几何形状和工艺参数对褶皱缺陷的影响。为了消除折痕缺陷,研究了敏感参数耦合对折痕缺陷的影响。研究发现,流动成形过程中加强筋与槽壁之间的间隙是形成褶皱缺陷的主要因素,其在交叉区域的缺陷大于TS和LS,并在后续成形过程中形成表面凹坑。最后,表面凹坑在材料周向流动的压缩下发展为褶皱缺陷。参数化分析表明,轧辊攻角、槽角半径和轧辊旋转轨迹对褶皱缺陷的发展较为敏感。通过耦合任意两个敏感参数,可以进一步削弱褶皱缺陷。通过同时使用这三种方法,可以完全消除褶皱缺陷。研究结果为提高带正交加强筋的铝合金圆柱流动成形质量提供了方法和指导。


Stress localization investigation of additively manufactured GRCop-42 thin-wall structure

Subhadip Sahoo, Mohammad M. Keleshteri, Jason R. Mayeur, Kavan Hazeli

doi:10.1016/j.tws.2024.112022

增材制造GRCop-42薄壁结构应力局部化研究

A full-field crystal plasticity (CP) framework is presented for the GRCop-42 alloy to study microscopic mechanical behavior and local stress heterogeneities. The microstructures of additively manufactured (AM) materials are often unique relative to conventionally processed materials, and the local thermal histories drive these differences during the build process. These thermal histories depend on the process parameters (laser power, scan speed, and scan strategy) and the part geometry. Prior research has shown that the mechanical properties of thin-walled structures can vary significantly with wall thickness due to changes in the thermal boundary conditions during manufacturing. It is, therefore, desirable to perform CP simulations based on the phenomenological constitutive model to predict the local mechanical responses induced by microstructural heterogeneities. This work generates representative microstructures based on experimentally collected grain information (i.e., texture) for grain scale stress analysis, and the material constitutive parameters are calibrated using the experimental mechanical testing data. We specifically investigated the effect of crystallographic texture and grain morphologies on the size-dependent mechanical properties of AM GRCop-42. The selection of appropriate material properties for implementing an effective free surface boundary condition and the influence of adjacent buffer layers are also discussed. Analysis of local field results reveals a strong correlation between stress localization and the initial grain orientation. However, no significant relationship between the misorientation of the individual adjacent grains and the average misorientation is observed.

提出了一种用于研究GRCop-42合金微观力学行为和局部应力非均质性的全场晶体塑性框架。与传统加工材料相比,增材制造(AM)材料的微观结构通常是独特的,而在构建过程中,局部热历史驱动了这些差异。这些热历史取决于工艺参数(激光功率、扫描速度和扫描策略)和零件几何形状。先前的研究表明,由于制造过程中热边界条件的变化,薄壁结构的力学性能会随着壁厚的变化而发生显著变化。因此,需要基于现象学本构模型进行CP模拟,以预测微观结构非均质性引起的局部力学响应。本工作基于实验收集的晶粒信息(即织构)生成具有代表性的微观组织,用于晶粒尺度应力分析,并利用实验力学测试数据校准材料本构参数。我们专门研究了晶体织构和晶粒形态对AM GRCop-42的尺寸相关力学性能的影响。为实现有效的自由表面边界条件选择合适的材料性能以及相邻缓冲层的影响也进行了讨论。局部实测结果分析表明,应力局部化与初始晶粒取向之间存在较强的相关性。然而,单个相邻晶粒的取向偏差与平均取向偏差之间没有显著的关系。


Topology optimization of stiffened revolution shell structures using multi-regional anisotropic MFSE method

Zhonghao Gao, Yan Li, Lili Fu, Kai Yang, Yangjun Luo

doi:10.1016/j.tws.2024.112030

基于多区域各向异性MFSE方法的加劲旋转壳结构拓扑优化

Stiffened revolution shell structures, prevalent in thin-walled load-bearing components across engineering disciplines, pose challenges in optimizing structural load-bearing capacity while maintaining ease of manufacturability and regularity of the structure. This paper presents an innovative anisotropic correlation-based material field series expansion (MFSE) method for topology optimization of stiffened revolution shell structures with multi-region strategy. In contrast to classical continuum topology optimization methods, the proposed approach directly represents regular stiffeners and provides smooth structural boundary description, without external manufacturing constraints. Leveraging the unique characteristics of revolution shell structures, a single anisotropic material field depicts uniformly oriented regular straight stiffeners organized into clusters. Multiple clusters of stiffeners are derived from two fundamental orthogonal stiffener clusters and integrated into a unified topological configuration through an innovative superposition function. Throughout the optimization process, the number, location and size of the optimized stiffeners are entirely determined by the specific problem and optimization procedure without necessitating special initial guess. Moreover, customizing or optimizing the shape of stiffener clusters to accommodate diverse loading conditions can be achieved through predefined structural forms. Ultimately, several numerical examples are solved using a gradient-based optimization algorithm incorporating the provided design sensitivity analysis program, validating the effectiveness of the proposed method.

在工程学科薄壁承重部件中普遍存在的加筋转壳结构,在保持结构易于制造性和规律性的同时,对优化结构承载能力提出了挑战。提出了一种新颖的基于各向异性相关的材料场序列展开(MFSE)方法,用于多区域加筋旋转壳结构拓扑优化。与传统的连续体拓扑优化方法相比,该方法直接表示规则加强筋,并提供平滑的结构边界描述,不受外部制造约束。利用旋转壳结构的独特特性,单一的各向异性材料场描绘了组织成簇的均匀定向规则直加强筋。从两个基本的正交加劲筋簇中衍生出多个加劲筋簇,并通过创新的叠加函数集成为统一的拓扑构型。在整个优化过程中,优化加强筋的数量、位置和尺寸完全由具体问题和优化程序决定,无需特别的初始猜测。此外,通过预定义的结构形式,可以定制或优化加强筋簇的形状,以适应不同的加载条件。最后,结合所提供的设计灵敏度分析程序,用基于梯度的优化算法求解了几个数值算例,验证了所提方法的有效性。


Verification of Euler–Bernoulli beam theory model for wind blade structure analysis

Pratiwi Fudlailah, David H. Allen, Roger Cordes

doi:10.1016/j.tws.2024.111989

欧拉-伯努利梁理论模型在风叶片结构分析中的验证

This paper presents a computational tool for analyzing the structural response of wind turbine blades using the advanced Euler–Bernoulli Beam theory. The objective is to achieve efficient computation of blade structural response under aerodynamic loading without sacrificing computational accuracy. This study involves the development of a Python-based computer program as a numerical tool, which utilizes inputs such as blade geometry and aerodynamic loading from Blade Element Momentum theory. The program outputs axially varying moments of inertia, spatial deflections of the blade, and stress distributions within the blade. The numerical tool is verified by comparing the results with both analytical solutions and far more time-consuming commercial finite element solvers. One of the key contribution of this research is the application of the polygon algorithm, which efficiently calculates the moments of inertia of web-stiffened turbine blades along the blade length. It is shown herein that this algorithm significantly reduces computational time while maintaining numerical accuracy as compared to the results obtained from commercially available finite element codes. The study confirms that the advanced Euler–Bernoulli beam theory, when combined with the polygon algorithm, is capable of accurately predicting the structural response of cambered and twisted wind turbine blades during the initial design phase.

本文提出了一种利用先进的欧拉-伯努利梁理论分析风力机叶片结构响应的计算工具。目的是在不牺牲计算精度的前提下,实现气动载荷下叶片结构响应的高效计算。本研究涉及开发基于python的计算机程序作为数值工具,该程序利用叶片几何形状和叶片单元动量理论的气动载荷等输入。该程序输出轴向变化的惯性矩、叶片的空间挠度和叶片内的应力分布。通过将结果与解析解和更耗时的商业有限元解进行比较,验证了数值工具的有效性。本研究的关键贡献之一是多边形算法的应用,该算法有效地计算了腹板加筋涡轮叶片沿叶片长度的转动惯量。本文表明,与商业上可用的有限元代码获得的结果相比,该算法在保持数值精度的同时显著减少了计算时间。研究证实,先进的欧拉-伯努利梁理论与多边形算法相结合,能够准确预测弯曲和扭曲风力发电机叶片在初始设计阶段的结构响应。


Numerical investigation of joinability and forming quality improvement on self-piercing riveting process with varying sheet stack combinations

Chao Wang, Zhanpeng Du, Aiguo Cheng, Zhicheng He

doi:10.1016/j.tws.2024.112017

不同板堆组合自穿孔铆接性能及成形质量改善的数值研究

Reducing complexity and increasing efficiency of the self-piercing riveting (SPR) process in joining varying sheet stack combinations by reducing the required rivet-die combinations have attracted great attention in the automobile industry. In this paper, the SPR joinability and the joining ranges of material strength and thickness of three types of stack combinations (e.g., steel-aluminium (SA), aluminium-aluminium (AA), and aluminium-steel (AS)) are investigated. In particular, the forming quality improvement process is developed to solve the forming quality defects generated in the riveting process. Two-dimensional axisymmetric finite element (FE) models are developed for each stack combination to simulate the SPR process, and the effects of rivet hardness, die type, sheet material and sheet thickness on the SPR joinability are studied numerically. The results show that the SPR joinability decreases with the increase in the thickness ratio, and the SPR joinability approaches zero when the thickness ratio exceeds 1.47. The rivet H4 and rivet H6 with a flat die can achieve higher SPR joinability compared to rivet H1. Specifically, the rivet H4 is suitable for joining the AA stack, and the rivet H6 is suitable for joining the SA and AS stacks. The average undercut ratio increases with the increase in rivet hardness, while a decreasing tendency is observed with the increase in thickness ratio. The rivet stiffness and hardness can be adjusted to solve the forming quality parameter defects and overcome upsetting deformation defects. Switching the riveting direction for the large thickness ratios (1.47 and 2.08) has proven to be an effective method to achieve successful joining.

通过减少铆钉与模具的组合,降低不同板层组合的自穿孔铆接的复杂性,提高其效率,已成为汽车工业关注的焦点。本文研究了钢-铝(SA)、铝-铝(AA)和铝-钢(AS)三种堆叠组合的SPR接合性以及材料强度和厚度的接合范围。特别针对铆接过程中产生的成形质量缺陷,开发了成形质量改进工艺。建立了各叠层组合的二维轴对称有限元模型,对SPR焊接过程进行了数值模拟,研究了铆钉硬度、模具类型、板材材料和板材厚度对SPR焊接性能的影响。结果表明:随着厚度比的增大,SPR的可焊性逐渐降低,当厚度比超过1.47时,SPR的可焊性趋于零;与铆钉H1相比,带平模的铆钉H4和铆钉H6可以获得更高的SPR接合性。具体来说,铆钉H4适用于连接AA堆栈,铆钉H6适用于连接SA和AS堆栈。平均凹边率随铆钉硬度的增大而增大,随厚度比的增大而减小。通过调整铆钉刚度和硬度,解决了成形质量参数缺陷,克服了镦粗变形缺陷。在大厚度比(1.47和2.08)时,改变铆接方向是实现成功连接的有效方法。


Capture Dynamics and Driving method of Origami capture mechanism in Orbit

Gang Wang, Qihui Zhang, Xi Hu, Kun Wang, Fei Yang, Honghao Yue

doi:10.1016/j.tws.2024.112019

折纸捕获机构在轨捕获动力学及驱动方法

This article focuses on the dynamic problem of origami capture mechanism capturing space debris in orbit. It delves into the envelope characteristics of the origami capture mechanism, analyzing the motion laws of its axisymmetric folding state. Furthermore, it establishes a kinematic model for the axisymmetric envelope of the origami capture mechanism. A rigid body dynamic model of the origami capture mechanism and a generalized torque equation for the hinge at the crease were established based on the D-H parameter method and the Lagrange method. The enveloping process of the origami capture mechanism in the microgravity environment was simulated using ADAMS software, and the accuracy of the rigid body dynamics model of the origami capture mechanism and the generalized moment equation of the hinge at the crease was verified. Using Ls-Dyna software to simulate the capture process of space debris by force-driven and displacement-driven flexible origami capture mechanisms in microgravity environments, the results show that displacement-driven origami capture mechanisms can quickly capture space debris and are suitable for capturing large-sized space debris; The force-driven origami capture mechanism can quickly complete envelope capture of space debris, suitable for capturing small-sized space debris.

研究了折纸捕获机构捕获在轨空间碎片的动力学问题。深入研究了折纸捕获机构的包络特性,分析了其轴对称折叠态的运动规律。建立了折纸捕获机构轴对称包络的运动学模型。基于D-H参数法和拉格朗日方法,建立了折纸捕获机构的刚体动力学模型和折痕处铰链的广义力矩方程。利用ADAMS软件对微重力环境下折纸捕获机构的包络过程进行了仿真,验证了折纸捕获机构刚体动力学模型和折痕处铰链广义力矩方程的准确性。利用Ls-Dyna软件模拟了在微重力环境下力驱动和位移驱动柔性折纸捕获机构对空间碎片的捕获过程,结果表明:位移驱动折纸捕获机构能够快速捕获空间碎片,适合于捕获大尺寸空间碎片;力驱动折纸捕获机构能快速完成空间碎片包络捕获,适用于小尺寸空间碎片的捕获。


Stiffness and ultimate strength of multi-ring-stiffened tube-gusset X-joints with dual-function stiffeners

Songzhao Qu, Jun Yuan, Quan Zhang, Qing Sun

doi:10.1016/j.tws.2024.112021

带双功能加强筋的多环加筋管扣板x型节点的刚度和极限强度

Tube-gusset (TG) joints that use stiffener plates as connecting plates for the crossarm chord are the main method for joining chords to tower bodies of transmission steel pipe towers. These joints experience the highest compression loads of the entire transmission tower structure. This study presents experimental research, numerical simulations, and theoretical analysis on the TG joint with a five-ring stiffener, where the middle stiffener plate serves as a connecting plate (referred to as C-Stiffener). This study elucidates the failure mechanism and mechanical characteristics of the C-Stiffener, identifies the key factors influencing its local buckling under compression, and proposes a stiffness calculation method for this type of stiffener plate. A calculation approach for the ultimate bearing capacity of the C-Stiffener is established by utilising its stiffness-deformation curve and a calculation method for the ultimate bearing capacity of the five-ring-stiffened TG joint under axial compression loading is proposed. The findings of this study can provide guidance for the meticulous design of joints between the crossarms and bodies of steel pipe transmission towers, thereby ensuring the safety and stability of transmission lines.

采用加劲板作为横臂弦连接板的管扣节接是传输钢管塔与塔体连接弦的主要方式。这些节点承受着整个输电塔结构中最高的压缩载荷。本文对中间加劲板作为连接板(简称c -加劲板)的五环加劲板TG接头进行了实验研究、数值模拟和理论分析。阐明了c型加劲板的破坏机理和力学特性,确定了影响c型加劲板受压局部屈曲的关键因素,提出了c型加劲板的刚度计算方法。利用c型加筋刚度-变形曲线建立了c型加筋极限承载力的计算方法,提出了轴压载荷下五环加筋TG节点极限承载力的计算方法。研究结果可为钢管输电塔横臂与塔身连接处的精细设计提供指导,从而保证输电线路的安全稳定。



来源:复合材料力学仿真Composites FEM
ACTMechanicalLS-DYNAAdditiveSystem振动复合材料拓扑优化汽车增材声学焊接理论电机材料控制模具
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首次发布时间:2024-11-14
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【新文速递】2024年5月3日复合材料SCI期刊最新文章

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The elongation at break and tensile strength of TPPA@PAO-Co/PAN increased by 36.5 % and 45.4 % due to the formed three-dimensional cross-linked supramolecular network among TPPA@PAO, Co2+ and PAN. Furthermore, the limiting oxygen index of TPPA@PAO-Co/PAN increased from 17.3 % of the control PAN to 33.7 %. The peak of heat release rate, total heat release, peak of smoke production rate, total smoke production and CO production rate were reduced by 78.1 %, 63.5 %, 81.1 %, 85.0 % and 73.1 %, respectively. The work developed a novel approach for fabricating PAN composite fibers with simultaneous flame retardant, smoke suppression and enhanced mechanical properties, expanding its application field.为制备具有优异阻燃、抑烟和增强力学性能的聚丙烯腈(PAN)复合纤维,合成了一种新型水不溶性生物质阻燃剂TPPA@PAO,将其与PAN纺丝液混纺,以Co2+溶液为混凝浴制备改性PAN复合纤维(TPPA@PAO-Co/PAN)。由于TPPA@PAO、Co2+和PAN之间形成三维交联超分子网络,TPPA@PAO-Co/PAN的断裂伸长率和抗拉强度分别提高了36.5% %和45.4% %。此外,TPPA@PAO-Co/PAN的极限氧指数由对照PAN的17.3 %提高到33.7 %。放热速率峰值、总放热速率峰值、产烟速率峰值、总产烟速率和CO速率分别降低了78.1 %、63.5 %、81.1 %、85.0% %和73.1 %。本研究为制备同时具有阻燃、抑烟和增强力学性能的PAN复合纤维开辟了一条新途径,拓展了其应用领域。Fabrication of TiB2/6061Al composite with tailoring heterostructure and superior mechanical properties and investigation on deformation behaviorsZhigang Li, Liang Chen, Zhenming Yue, Lihua Qian, Biaohua Que, Cunsheng Zhangdoi:10.1016/j.compositesa.2024.108245 具有定制异质结构和优异力学性能的TiB2/6061Al复合材料的制备及变形行为研究Overcoming the trade-off between strength and ductility remains a critical challenge for Al matrix composites. Here, TiB2/6061Al composites with harmonic and lamellar heterostructures were fabricated via hot press sintering by altering the size of Al powders. The discontinuous dynamic recrystallization (DDRX) and DRX take place, with DDRX being particularly promoted by the presence of fine grains around coarse grains. The activated slip systems of the grains with similar orientations are nearly identical during tension, while those of the randomly orientated grains vary significantly. Geometrically necessary dislocations form in fine grains due to their limited deformation compatibility, and also in the boundaries between fine and coarse grains. The heterostructured composite exhibits a superior strength-ductility synergy compared to the homogeneous composite, attributed to the hetero-deformation induced strengthening and dislocation strengthening. 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Here, a nacre-mimetic composite with anti-impact, force-sensing and thermal-regulating performance was developed by introducing shear-stiffening gel (SSG) into montmorillonite (MMT)-MXene hierarchical network. A 4 mm-thick SSG-MMT-MXene (SMM) composite effectively reduced the impact force from 1308.1 N to 370.4 N, which was superior to many engineering materials. SMM implemented significant improvement of both structural stability and environmental adaptability. In addition, its ΔR/R0 increased from 230.3% to 14608.6% under impact, indicating SMM’s potential as an electronic skin for environmental monitoring. Besides, its temperature reached 110.4 °C at 9 V loading-voltage and remained stable during multiple loading-unloading stimuli. Eventually, an SMM-based customizable intelligent protector was developed, enabling the detection of environmental variations and providing protection against mechanical impact and cold conditions. This novel strategy showed promising applications in lightweight body-armor and wearable electronics.开发具有高能量耗散性能的结构复合材料对于个人防护装备的发展至关重要。在这里,通过在蒙脱石(MMT)-MXene 分层网络中引入剪切增韧凝胶(SSG),开发出了一种具有抗冲击、力传感和热调节性能的珍珠岩仿生复合材料。4 毫米厚的 SSG-MMT-MXene 复合材料(SMM)有效地将冲击力从 1308.1 牛顿减少到 370.4 牛顿,优于许多工程材料。SMM 显著提高了结构稳定性和环境适应性。此外,在冲击力作用下,其 ΔR/R0 从 230.3% 增加到 14608.6%,这表明 SMM 具有作为环境监测电子皮肤的潜力。此外,在 9 V 加载电压下,其温度达到 110.4 °C,并在多次加载-卸载刺 激下保持稳定。最终,我们开发出了一种基于 SMM 的可定制智能保护器,能够检测环境变化,并提供机械冲击和寒冷条件下的保护。这种新颖的策略在轻型护甲和可穿戴电子设备中的应用前景广阔。来源:复合材料力学仿真Composites FEM

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