【新文速递】2023年10月7日固体力学SCI期刊最新文章

今日更新：International Journal of Solids and Structures 5 篇，Journal of the Mechanics and Physics of Solids 1 篇，International Journal of Plasticity 1 篇，Computer Methods in Applied Mechanics and Engineering 2 篇，Thin-Walled Structures 1 篇

International Journal of Solids and Structures

Light-powered self-propelled trolley with a liquid crystal elastomer pendulum motor

Zuo Wei, Sun Tianle, Dai Yuntong, Li Kai, Zhao Jun

doi:10.1016/j.ijsolstr.2023.112500

配备液晶弹性摆式电机的轻型自走小车

Conventional liquid crystal elastomer (LCE)-based robots require complex controllers and bulky power supplies, limiting their applications in areas such as microrobots and soft robots. In this paper, a light-powered self-propelled trolley with a LCE pendulum motor is proposed, and the dynamics of its self-propelled motion is investigated theoretically. Under steady illumination, the periodic radial contraction and relaxation of LCE can trigger the trolley to move forward through the self-rotation of the LCE pendulum. The coupling of the optically-induced deformation with its motion facilitates the energy input from ambient illumination to compensate for the damping dissipation so as to maintain the sustained motion. Through theoretical modeling and numerical calculations, three typical motion states of the LCE pendulum are identified, namely static state, self-oscillation state and self-rotation state. Among them, the LCE pendulum can propel the trolley when it is self-rotating. The influences of different physical parameters on the system motion are studied quantitatively. The results show that the period of the simple pendulum and the trolley speed can be controlled by adjusting the illumination range, optical intensity, damping coefficient of pendulum and damping coefficient of trolley. The light-powered self-propelled trolley constructed in current paper does not require complex controllers or self-contained power supplies, and possesses the characteristics of simple structure, light weight and energy efficient, which is of latent applied value in microrobots, soft robots and other fields.

基于液晶弹性体（LCE）的传统机器人需要复杂的控制器和笨重的电源，限制了其在微型机器人和软体机器人等领域的应用。本文提出了一种采用 LCE 摆式电机的光动力自走小车，并对其自走运动的动力学特性进行了理论研究。在稳定光照下，LCE 的周期性径向收缩和松弛可通过 LCE 摆的自转触发小车前进。光学诱导的形变与其运动的耦合，有利于从环境光照中输入能量来补偿阻尼耗散，从而维持持续运动。通过理论建模和数值计算，确定了 LCE 摆的三种典型运动状态，即静止状态、自振状态和自转状态。其中，LCE 摆在自转状态下可以推动小车。定量研究了不同物理参数对系统运动的影响。结果表明，可以通过调节光照范围、光照强度、摆锤阻尼系数和小车阻尼系数来控制单摆周期和小车速度。本文构建的光动力自走小车不需要复杂的控制器或自带电源，具有结构简单、重量轻、高效节能等特点，在微型机器人、软体机器人等领域具有潜在的应用价值。

Heterogeneous beam element for multiscale modeling of non-prismatic composite beam-like structures

Chiu Rong, Yu Wenbin

doi:10.1016/j.ijsolstr.2023.112490

用于非棱柱复合梁状结构多尺度建模的异质梁元素

Anisotropy, heterogeneity, and geometry make full system-level three-dimensional (3D) finite element analysis (FEA) simulation of a real composite beam-like structure, such as wind blades, impossible due to limitations on computation resources. A popular approach is to cut the structure into multiple cross-sections, from which the beam properties based on the Euler–Bernoulli or Timoshenko beam models are extracted using two-dimensional (2D) cross-sectional analyses. These properties are then utilized in beam elements for system-level analyses. However, the mechanics behind 2D cross-sectional analyses are based on prismatic beams, limiting the accuracy of this approach on non-prismatic structures, especially in predicting stresses. In this work, we present a new multiscale method based on a novel application of the recently developed Mechanics of Structure Genome to analyze the beam-like non-prismatic composite structure. The beam-like structure is homogenized into a series of 3-node Heterogeneous Beam Elements (HBE) with 18 × 18 effective beam element stiffness matrices, which are used as input for one-dimensional (1D) beam analysis using Abaqus User Element subroutine (UEL). Using the macroscopic beam analysis results as input, we can also perform dehomogenization to predict the stresses and strains in the original structure. We use three examples (a prismatic composite beam, an isotropic homogeneous tapered beam, and a composite tapered beam) to demonstrate the capability of HBE and show its advantages over the traditional cross-sectional analysis approach. HBE can capture macroscopic behavior and detailed stresses due to non-prismatic geometry. HBE provides a new concept to model non-prismatic composite beams by modeling heterogeneous beam-like structures into equivalent beam elements rather than beam properties of material points of the reference line.

由于计算资源的限制，各向异性、异质性和几何形状使得对风力叶片等实际复合材料梁状结构进行全系统级三维（3D）有限元分析（FEA）模拟成为不可能。一种常用的方法是将结构切割成多个横截面，然后通过二维（2D）横截面分析提取基于欧拉-伯努利或季莫申科梁模型的梁属性。然后在梁元素中利用这些属性进行系统级分析。然而，二维截面分析背后的力学原理是基于棱柱梁的，这限制了这种方法在非棱柱结构上的准确性，尤其是在预测应力方面。在这项工作中，我们提出了一种新的多尺度方法，该方法基于最近开发的结构力学基因组的新应用，用于分析梁状非棱柱复合结构。我们将类梁结构均匀化为一系列具有 18 × 18 有效梁元素刚度矩阵的 3 节点异质梁元素（HBE），并使用 Abaqus 用户元素子程序（UEL）将其作为一维（1D）梁分析的输入。使用宏观梁分析结果作为输入，我们还可以进行去均质化，以预测原始结构中的应力和应变。我们用三个例子（棱柱复合梁、各向同性均质锥形梁和复合锥形梁）来展示 HBE 的能力，并显示其与传统截面分析方法相比的优势。HBE 可以捕捉宏观行为和非棱柱几何形状引起的详细应力。通过将异质梁状结构建模为等效梁元素，而不是参考线材料点的梁属性，HBE 为非棱柱复合梁建模提供了一个新概念。

Investigation of stress states around a finite-height crack

Chen Yifeng, Adams George G., Hills David A.

doi:10.1016/j.ijsolstr.2023.112499

有限高度裂缝周围应力状态研究

This paper is concerned with the analysis of a crack that has a finite-height at its crack tip, loaded under Mode I and II loading. The stress field around the “crack-height” region has been analysed and local Williams’ eigensolutions collocated using the H-integral. Results of the analysis help us to predict which one of the three possible places that fracture failure could occur is most likely, i.e., (1) at the middle plane of the crack tip (collinear with the sharp crack problem), (2) at the “notch corner” or (3) at the intermediate plane between the notch corner and the middle plane (intermediate state). A practical example of an infinite plane with a rectangular shaped crack has also been shown to demonstrate the practical use of the results of this paper.

本文主要分析在模式 I 和模式 II 载荷作用下，裂纹顶端具有有限高度的裂纹。对 "裂纹高度 "区域周围的应力场进行了分析，并使用 H 积分对局部 Williams 特征进行了定位。分析结果有助于我们预测断裂失效最可能发生的三个位置，即 (1) 裂纹尖端的中间平面（与尖锐裂纹问题相邻），(2) "缺口角 "或 (3) 缺口角和中间平面之间的中间平面（中间状态）。本文还举例说明了一个无限平面上的矩形裂缝，以证明本文结果的实用性。

Multi-configuration rigidity: Theory for statically determinate structures

Dorn Charles, Pellegrino Sergio

doi:10.1016/j.ijsolstr.2023.112502

多配置刚度：静定结构理论

This paper introduces the concept of multi-configuration rigidity for kinematically indeterminate structures with elastic springs and unilateral constraints. A simple example is provided by a structure with a single mechanism and a spring that engages two different unilateral constraints. In each of these configurations, the structure can rigidly support loads up to a critical magnitude at which the unilateral constraints become inactive. The general design problem of embedding springs throughout a structure to achieve multi-configuration rigidity, with multiple unilateral constraints and springs, is studied. This problem is cast as a linear program that maximizes the critical loads required to break free from the unilateral constraints, in all target configurations. This problem can be efficiently solved with guarantees of optimality. The formulation is generally applicable to a variety of discrete structures (e.g., linkages, pin-jointed bars, or origami) with unilateral constraints (e.g., contacts or cables).

本文介绍了具有弹性弹簧和单边约束的运动学不确定结构的多配置刚度概念。一个简单的例子是一个具有单个机构和弹簧的结构，弹簧与两个不同的单边约束相啮合。在每种配置中，结构都能刚性支撑负载，直至达到单边约束失效的临界值。本文研究了在整个结构中嵌入弹簧以实现具有多个单边约束和弹簧的多配置刚性的一般设计问题。该问题被视为一个线性程序，在所有目标配置中，最大化挣脱单边约束所需的临界载荷。该问题可以高效求解，并保证最优性。该公式一般适用于各种具有单边约束（如触点或缆线）的离散结构（如连杆、针接杆或折纸）。

A light-powered liquid crystal elastomer semi-rotary motor

Li Kai, Qian Peipei, Hu Haoyu, Dai Yuntong, Ge Dali

doi:10.1016/j.ijsolstr.2023.112509

光动力液晶弹性体半旋转电机

Self-excited oscillators are characterized by active energy harvesting from the stable external environment, autonomy and portability, which allow them to act as engines to drive other working devices. Taking inspiration from the pump drill, a semi-rotary motor consisting of a motor rotor and three liquid crystal elastomer (LCE) fibers is constructed in this paper, which can realize self-rotation under stable illumination. Considering the existing twisted wire model and the dynamic LCE model, a nonlinear dynamics model for the semi-rotary motor under stable illumination is established. Numerical calculations witness the existence of two motion modes for the semi-rotary motor under stable illumination, namely the static mode and the self-rotation mode. Under stable illumination, the light-driven contraction of twisted segments in LCE fibers for the winding state can trigger the self-rotation and maintain the continuous periodic motion through the interrelationship between optical energy and damping dissipation. The critical conditions required to trigger the self-rotation are also investigated in detail, as well as the crucial system parameters affecting the self-rotation frequency and amplitude. The proposed self-rotating semi-rotary motor has a simple structure, customizable dimensions and high speed, prompting its potential use in soft robots, energy harvesters, and micro-machines.

自激振荡器的特点是从稳定的外部环境中主动采集能量，具有自主性和便携性，可以作为引擎驱动其他工作装置。受泵钻的启发，本文构建了一种由电机转子和三根液晶弹性纤维（LCE）组成的半旋转电机，它可以在稳定的光照下实现自旋转。考虑到现有的扭线模型和动态 LCE 模型，本文建立了半旋转电机在稳定光照下的非线性动力学模型。数值计算证明了半旋转电机在稳定光照下存在两种运动模式，即静态模式和自转模式。在稳定光照下，LCE 光纤中缠绕状态的捻段在光驱动下收缩，通过光能和阻尼耗散的相互关系触发自旋转并保持连续的周期运动。此外，还详细研究了触发自旋转所需的关键条件，以及影响自旋转频率和振幅的关键系统参数。所提出的自旋转半旋转电机具有结构简单、尺寸可定制和速度高的特点，有望用于软机器人、能量收集器和微型机械。

Journal of the Mechanics and Physics of Solids

Nonlinear mechanics of remodeling

Kumar Aditya, Yavari Arash

doi:10.1016/j.jmps.2023.105449

重塑的非线性力学

In this paper, we present a large-deformation formulation of the mechanics of remodeling. Remodeling is anelasticity with an internal constraint—material evolutions that are mass and volume-preserving. In this special class of material evolutions, the explicit time dependence of the energy function is via one or more remodeling tensors that can be considered as internal variables of the theory. The governing equations of remodeling solids are derived using a two-potential approach and the Lagrange-d’Alembert principle. We consider both isotropic and anisotropic solids and derive their corresponding remodeling equations. We study a particular remodeling of fiber-reinforced solids in which the fiber orientation is time-dependent in the reference configuration—SO(3)-remodeling. We define an additional remodeling energy, which is motivated by the energy spent in collagen fiber-reinforced living systems to remodel to enhance stiffness or strength in the direction of loading. We consider the examples of a solid reinforced with either one or two families of reorienting fibers and derive their remodeling equations. This is a generalization of some of the proposed remodeling equations in the literature. We study three examples of material remodeling, namely finite extensions and torsion of solid circular cylinders, which are universal deformations for incompressible isotropic solids and certain anisotropic solids. We consider both displacement and force-control loadings. Detailed parametric studies are included for the effects of various material and loading parameters on fiber remodeling. It is observed that during remodeling, there is a competition between the action of the internal strain energy function and the remodeling energy. For a given material, a remodeling process dominated by strain energy works to align fibers in a direction that minimizes strain energy. On the other hand, a remodeling process dominated by the remodeling energy aligns fibers in the direction of the maximum principal strain according to a constitutive choice. We finally linearize the governing equations of the remodeling theory and derive those of linear remodeling mechanics.

在本文中，我们提出了重塑力学的大变形公式。重塑是一种具有内部约束的弹性力学--材料演化是质量和体积保值的。在这一类特殊的材料演化中，能量函数的明确时间依赖性是通过一个或多个重塑张量实现的，这些张量可视为理论的内部变量。重塑固体的支配方程是利用双势能法和拉格朗日-达朗贝尔原理推导出来的。我们同时考虑了各向同性和各向异性固体，并推导出相应的重塑方程。我们研究了纤维增强固体的一种特殊重塑，在这种重塑中，参考构型中的纤维取向是随时间变化的。SO(3)-重塑。我们定义了一种额外的重塑能量，这种能量来自于胶原纤维加固的活体系统为增强加载方向的刚度或强度而进行重塑所消耗的能量。我们考虑了用一个或两个重新定向纤维系列加固固体的例子，并推导出它们的重塑方程。这是对文献中提出的一些重塑方程的概括。我们研究了材料重塑的三个例子，即实心圆柱体的有限延伸和扭转，它们是不可压缩各向同性固体和某些各向异性固体的普遍变形。我们同时考虑了位移和力控制载荷。详细的参数研究包括各种材料和加载参数对纤维重塑的影响。据观察，在重塑过程中，内部应变能函数的作用与重塑能之间存在竞争。对于给定的材料，应变能主导的重塑过程会使纤维向应变能最小的方向排列。另一方面，由重塑能主导的重塑过程会根据构成选择使纤维向最大主应变方向排列。最后，我们将重塑理论的控制方程线性化，并推导出线性重塑力学方程。

International Journal of Plasticity

Element-dependent evolution of chemical short-range ordering tendency of NiCoFeCrMn under irradiation

Zhou Yundi, Shi Tan, Li Jing, Wu Lu, Peng Qing, Lu Chenyang

doi:10.1016/j.ijplas.2023.103768

辐照下镍钴铁铬锰化学短程有序趋势的元素依赖性演化

The evolution of short-range order (SRO) structures under irradiation has a great impact on the mechanical properties of high-entropy alloys. In this study, the atomistic mechanism of the evolution of SRO during and after cascade collisions was investigated in NiCoFeCrMn by multiscale modeling using molecular dynamics and lattice kinetic Monte Carlo simulations. SRO structures could be destructed by cascade collisions in short time and recovered by atomic diffusion in a much longer time. The destruction rate depends on the primary knock-on atom energies in cascade collisions and shows a universal law with respect to the number of replacement-per-atom. The vacancy diffusion simulations reveal that the SRO recovery rates of different element pairs vary significantly due to the distinct diffusion rates. Consequently, the SRO state under irradiation differs from that in thermodynamic equilibrium due to the difference of destruction and recovery rate for each element pair. The evolution of SRO is a result of the competition between the destruction and recovery mechanisms and depends heavily on the irradiation conditions.

辐照下短程有序结构（SRO）的演变对高熵合金的力学性能有很大影响。本研究利用分子动力学和晶格动力学蒙特卡洛模拟，通过多尺度建模研究了级联碰撞过程中和碰撞后镍钴铁铬锰中短程有序结构演变的原子机制。级联碰撞可在短时间内破坏 SRO 结构，并在更长的时间内通过原子扩散恢复结构。破坏率取决于级联碰撞中的主要碰撞原子能量，并与每个原子的置换数量呈普遍规律。空位扩散模拟显示，由于扩散速率不同，不同元素对的 SRO 恢复速率差异很大。因此，由于每个元素对的破坏和恢复速率不同，辐照下的 SRO 状态与热力学平衡状态也不同。SRO 的演变是破坏和恢复机制竞争的结果，在很大程度上取决于辐照条件。

Computer Methods in Applied Mechanics and Engineering

Design and analysis of an exactly divergence-free hybridised discontinuous Galerkin method for incompressible flows on meshes with quadrilateral cells

Dean Joseph P., Rhebergen Sander, Wells Garth N.

doi:10.1016/j.cma.2023.116493

四边形单元网格上不可压缩流动的精确无发散混合非连续伽勒金方法的设计与分析

We generalise a hybridised discontinuous Galerkin method for incompressible flow problems to non-affine cells, showing that with a suitable element mapping the generalised method preserves a key invariance property that eludes most methods, namely that any irrotational component of the prescribed force is exactly balanced by the pressure gradient and does not affect the velocity field. This invariance property can be preserved in the discrete problem if the incompressibility constraint is satisfied in a sufficiently strong sense. We derive sufficient conditions to guarantee discretely divergence-free functions are exactly divergence-free and give examples of divergence-free finite elements on meshes with triangular, quadrilateral, tetrahedral, or hexahedral cells generated by a (possibly non-affine) map from their respective reference cells. In the case of quadrilateral cells, we prove an optimal error estimate for the velocity field that does not depend on the pressure approximation. Our analysis is supported by numerical results.

我们将不可压缩流动问题的混合非连续 Galerkin 方法推广到了非非线性单元，证明了在合适的元素映射下，这种推广方法保留了大多数方法无法保留的关键不变性，即规定力的任何非旋转分量都会被压力梯度精确平衡，并且不会影响速度场。如果不可压缩性约束在足够强的意义上得到满足，离散问题中就能保留这一不变性。我们推导出保证离散无发散函数完全无发散的充分条件，并举例说明了网格上的无发散有限元，网格上的三角形、四边形、四面体或六面体单元是由各自的参考单元映射（可能是非线性的）生成的。在四边形单元的情况下，我们证明了速度场的最佳误差估计值，该误差估计值与压力近似值无关。我们的分析得到了数值结果的支持。

Stabilized immersed isogeometric analysis for the Navier–Stokes–Cahn–Hilliard equations, with applications to binary-fluid flow through porous media

Stoter Stein K.F., van Sluijs Tom B., Demont Tristan H.B., van Brummelen E. Harald, Verhoosel Clemens V.

doi:10.1016/j.cma.2023.116483

纳维-斯托克斯-卡恩-希利亚德方程的稳定沉浸等距分析，应用于流经多孔介质的二元流体流动

Binary-fluid flows can be modeled using the Navier–Stokes–Cahn–Hilliard equations, which represent the boundary between the fluid constituents by a diffuse interface. The diffuse-interface model allows for complex geometries and topological changes of the binary-fluid interface. In this work, we propose an immersed isogeometric analysis framework to solve the Navier–Stokes–Cahn–Hilliard equations on domains with geometrically complex external binary-fluid boundaries. The use of optimal-regularity B-splines results in a computationally efficient higher-order method. The key features of the proposed framework are a generalized Navier-slip boundary condition for the tangential velocity components, Nitsche’s method for the convective impermeability boundary condition, and skeleton- and ghost-penalties to guarantee stability. A binary-fluid Taylor–Couette flow is considered for benchmarking. Porous medium simulations demonstrate the ability of the immersed isogeometric analysis framework to model complex binary-fluid flow phenomena such as break-up and coalescence in complex geometries.

二元流体流动可以使用纳维-斯托克斯-卡恩-希利亚德方程建模，该方程用扩散界面表示流体成分之间的边界。扩散界面模型允许二元流体界面的复杂几何形状和拓扑变化。在这项工作中，我们提出了一种沉浸式等距分析框架，用于求解具有几何形状复杂的二元流体外部边界的域上的纳维-斯托克斯-卡恩-希利亚德方程。通过使用最优规则 B-样条曲线，产生了一种计算高效的高阶方法。所提框架的主要特点是针对切向速度分量的广义纳维-滑移边界条件、针对对流不透性边界条件的尼采方法，以及保证稳定性的骨架和幽灵惩罚。为进行基准测试，考虑了二元流体 Taylor-Couette 流动。多孔介质模拟证明了沉浸等距分析框架能够模拟复杂的二元流体流动现象，如复杂几何形状中的破裂和凝聚。

Thin-Walled Structures

Natural frequencies of Prismatic and Tapered Composite Girders with Corrugated Steel Webs

Li Qiangbo, Zhou Man

doi:10.1016/j.tws.2023.111250

带波纹钢腹板的棱柱形和锥形复合梁的自然频率

The present study proposed an analytical formula to predict the natural frequencies of prismatic and tapered composite girders with corrugated steel webs (CSWs), and rigorously provides the derivation process. It is experimentally and numerically verified that the proposed formula is more applicable for predicting the natural frequencies of girders with CSWs, in comparison to the traditional formula based on Euler-Bernoulli beam theory. The study demonstrates that the traditional formula used for determining the natural frequencies of prismatic girders with CSWs leads to significant overestimation, mainly because it ignores the effects of shear deformation. The finite element (FE) simulation suggests that the free vibration mode shapes of tapered girders with CSWs exhibit sinusoidal patterns. Consequently, an equivalent stiffness method has been developed for accurately and conveniently estimating the natural frequencies of tapered girders with CSWs. This paper establishes a theoretical foundation for modifying the natural frequency calculation formula of prismatic and tapered girders with CSWs in current specifications, the research findings hold significant implications for the structural dynamic analysis and design of such girders.

本研究提出了预测带波纹钢腹板（CSW）的棱柱形和锥形复合梁固有频率的分析公式，并严格提供了推导过程。实验和数值验证表明，与基于欧拉-伯努利梁理论的传统公式相比，所提出的公式更适用于预测带 CSW 的大梁的固有频率。研究表明，用于确定带 CSW 的棱柱梁固有频率的传统公式会导致严重高估，这主要是因为它忽略了剪切变形的影响。有限元（FE）模拟表明，带 CSW 的锥形大梁的自由振动模式形状呈现正弦模式。因此，我们开发了一种等效刚度方法，用于准确、方便地估算带 CSW 的锥形梁的固有频率。本文为修改现行规范中带有 CSW 的棱柱梁和锥形梁的固有频率计算公式奠定了理论基础，其研究成果对此类梁的结构动态分析和设计具有重要意义。