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 4 篇
Evolution of fiber distributions in homogenized constrained mixture models of soft tissue growth and remodeling: Uniaxial loading
Gizzi Alessio, Cyron Christian J., Falcinelli Cristina, Vasta Marcello
doi:10.1016/j.jmps.2023.105491
软组织生长和重塑的均质约束混合物模型中纤维分布的演变:单轴加载
Growth and remodeling in soft tissue changes, in general, the orientation distribution of the collagen fibers in the tissue. So far, the governing principles are still incompletely understood. In this paper, we derive from the homogenized constrained mixture theory of soft tissue growth and remodeling - under some simplifying assumptions - a theoretical framework that enables simple analytical solutions that help to understand the evolution of the collagen fiber distribution in soft tissues during growth and remodeling under uniaxial loading. Our analysis suggests a natural tendency of the collagen fiber distribution to form a peak in the direction of loading and a spread increasing with the ratio of the fiber half-life time and the time constant governing loading-related fiber production. This observation helps to understand why in vivo collagen fiber reinforcement is typically organized in the form of (often von Mises-like) distributions with a finite spread. Our analysis also suggests a considerable history dependence of the fiber distribution evolution, which may explain why, in tissues under the same type of loading, sometimes considerably different fiber orientation distributions are observed.
软组织的生长和重塑一般会改变组织中胶原纤维的定向分布。迄今为止,人们对其原理的理解还很不全面。在本文中,我们根据软组织生长和重塑的均质约束混合物理论(在一些简化假设条件下)推导出了一个理论框架,该框架可提供简单的分析解决方案,有助于理解在单轴载荷作用下,软组织在生长和重塑过程中胶原纤维分布的演变。我们的分析表明,胶原纤维分布的自然趋势是在加载方向形成一个峰值,并随着纤维半衰期时间与加载相关纤维生成时间常数之比增加而扩散。这一观察结果有助于理解为什么体内胶原纤维加固通常以(通常是冯-米塞斯式的)有限扩散分布的形式组织。我们的分析还表明,纤维分布的演变与历史有相当大的关系,这或许可以解释为什么在同一种加载下的组织中,有时会观察到截然不同的纤维取向分布。
Low cycle fatigue behaviour of engineering metallic materials: Review on cyclic deformation micro-mechanism
Ghosh Atasi
doi:10.1016/j.mechmat.2023.104852
工程金属材料的低循环疲劳行为:循环变形微观机制综述
The micro-mechanism of low cycle fatigue deformation behaviour has been summarised, utilising the recent advances in the state-of-the-art facility for the characterisation of deformation microstructure, and micro-texture. Besides, recent development in the approach of numerical simulation of cyclic stress-strain behaviour of polycrystalline metallic materials at multi-scale has been discussed. It has been carried out by reviewing, and re-interpreting the evidences from the investigations carried out over the last few decades on several engineering metallic materials having critical applications in various industries. The understanding of the existing material behaviour will help us in the better characterisation of the low cycle fatigue deformation microstructure of the new generation metallic materials having complex microstructure.
利用最新的先进设备对变形微观结构和微观纹理进行表征,总结了低循环疲劳变形行为的微观机制。此外,还讨论了多晶金属材料多尺度循环应力应变行为数值模拟方法的最新发展。本研究通过回顾和重新解释过去几十年来对各行各业中具有重要应用价值的几种工程金属材料的研究证据来进行。对现有材料行为的理解将有助于我们更好地描述具有复杂微观结构的新一代金属材料的低循环疲劳变形微观结构。
Role of grain boundary crystallography on void growth in FCC metals
Christodoulou Paul G., Zecevic Miroslav, Lebensohn Ricardo A., Beyerlein Irene J.
doi:10.1016/j.ijplas.2023.103803
晶界晶体学对催化裂化金属中空隙增长的作用
The growth of an isolated spherical void at and near a grain boundary or a triple junction is studied by means of full-field crystal plasticity simulations with explicit representation of the void. The particular focus of this work is on the role of crystallography (grain orientations, grain boundary misorientation and inclination angle with respect to the largest component of the applied stress) and type of loading on void growth. To examine fundamental aspects of void/grain boundary interactions, a three-dimensional large-strain elasto-viscoplastic fast-Fourier transform (LS-EVP-FFT) model with axisymmetric tensile periodic boundary contditions was extended and adapted for this purpose. The use of periodic boundary conditions allow for a garnering of fundamental insight, but cannot fully capture the behavior of a real material. It was found that grain orientation was the primary crystallographic feature governing void growth in strain-rate controlled simulations. For strains small enough to not significantly alter the local geometry, the overall growth of the void in bicrystal boundaries was not strongly affected by grain boundary inclination angle when the grain orientations were set with respect to the axis of loading, but the relative amount of void growth experienced within each grain in a bicrystal or tri-crystal was strongly dependent on the grain boundary inclination angle. We found a subset of orientations with similar void growth in single crystals that exhibit faster void growth in bicrystals. When placed primarily in one grain at or near the grain boundary, the total void growth was consistent with void growth at the grain boundary, but the void remained in the original grain without any shift towards the other, regardless of crystallographic character.
通过明确表示空隙的全场晶体塑性模拟,研究了晶界或三重交界处及附近孤立球形空隙的生长。这项工作的重点是晶体学(晶粒取向、晶界错向和相对于外加应力最大分量的倾角)和加载类型对空隙生长的作用。为了研究空隙/晶界相互作用的基本方面,对带有轴对称拉伸周期性边界条件的三维大应变弹塑性-粘弹性快速傅里叶变换(LS-EVP-FFT)模型进行了扩展和调整。使用周期性边界条件可以获得基本的洞察力,但不能完全捕捉真实材料的行为。研究发现,在应变速率控制模拟中,晶粒取向是支配空隙增长的主要晶体学特征。在应变小到不会显著改变局部几何形状的情况下,当晶粒取向设定为相对于加载轴时,双晶边界中空隙的整体增长并不受晶粒边界倾角的强烈影响,但双晶或三晶中每个晶粒内空隙增长的相对量却与晶粒边界倾角密切相关。我们发现,在单晶中具有类似空隙增长的取向子集在双晶中表现出更快的空隙增长。当主要置于晶界处或接近晶界处的一个晶粒时,总的空隙增长与晶界处的空隙增长一致,但空隙仍保留在原来的晶粒中,没有向另一个晶粒转移,而与晶体学特征无关。
A symplectic analytical wave propagation model for forced vibration of thin plate with acoustic black hole indentation
Zhang Sen, Cheng Qingfeng, Ma Yongbin, Deng Zichen
doi:10.1016/j.tws.2023.111339
带有声学黑洞压痕的薄板受迫振动的交点分析波传播模型
In recent years, acoustic black holes (ABHs) have been revealed as an effective bending wave control technology and widely used to regulate the vibration and noise reduction performance of plate structure. However, the isolation effect of most traditional ABH plate can only be aroused at frequencies above the cut-off frequency. In order to widen the frequency range of the ABH effect, this paper embedded single and multiple ABH indentations at the end of plate. For the forced vibration response of the ABH indentation plate, an analytical wave propagation model was proposed based on the symplectic method. The governing equations of bending vibration of thin plate was first introduced into the symplectic dual system, then the symplectic analytical solution of wave propagation parameters and waveforms were obtained. A Gaussian-discretization scheme was used to discretize the ABH indentation, whereas the proposed method was used to evaluate the wave amplitude. The vibration response was finally obtained using the superposition principle and wave propagation, reflection, and transmission relationships. The effectiveness of the proposed method was verified using the finite element results. The results showed that the ABH indentation plate, especially the plate with multiple ABH indentations, had significant vibration reduction performance. Considering that embedding ABH indentation can weaken the structural rigidity of the plate, the ABH indentation plate with reinforcing stiffeners was then proposed to alleviate this limitation, and the influence of the width and quantity of reinforcing stiffeners on the vibration response was studied. The results indicated that the increase of width will to some extent weaken the ABH effect, and the quantity of stiffeners had a significant impact on the ABH effect.
近年来,声学黑洞(ABHs)作为一种有效的弯曲波控制技术,被广泛应用于调节板结构的减振降噪性能。然而,大多数传统 ABH 板的隔振效果只能在截止频率以上的频率下产生。为了拓宽 ABH 效果的频率范围,本文在板端嵌入了单个和多个 ABH 压痕。针对 ABH 压痕板的受迫振动响应,提出了一种基于交点法的解析波传播模型。首先将薄板弯曲振动的支配方程引入交点二元系统,然后得到波传播参数和波形的交点解析解。使用高斯离散化方案对 ABH 压痕进行离散化,并使用建议的方法评估波幅。最后利用叠加原理和波的传播、反射和透射关系得到了振动响应。利用有限元结果验证了所提方法的有效性。结果表明,ABH 压痕板,尤其是具有多个 ABH 压痕的板,具有显著的减振性能。考虑到嵌入 ABH 压痕会削弱板的结构刚度,为缓解这一限制,提出了带有加强加劲件的 ABH 压痕板,并研究了加强加劲件的宽度和数量对振动响应的影响。结果表明,宽度的增加会在一定程度上削弱 ABH 效果,而加强筋的数量对 ABH 效果有显著影响。
Nonlinear vibration of porous truncated conical shell under unified boundary condition and mechanical load
Hao Y.X., Li H., Zhang W., Gu X.J., Yang S.W.
doi:10.1016/j.tws.2023.111355
统一边界条件和机械载荷下多孔截顶锥形壳的非线性振动
The aim of this article is to research nonlinear vibration responses of a metal porous truncated conical shell undergoing mechanical harmonic loads in thickness direction. The artificial spring technique is employed to unify boundary condition which can arrive at arbitrary classical boundary condition in real-word by changing the stiffness of springs. Utilizing Hamilton's principle, theoretical formulations of the conical shell are developed in view of FSDT and von-Kármán geometric relation. Afterwards, by employing generalized differential quadrature method (GDQM), the governing equation of nonlinear vibration in the form of partial differential equation is truncated and discretized into an ordinary differential equation which is a high-dimensional nonlinear dynamic system described in physical space rather than the mode space. On this basis, the analysis of effect of exciting frequency on the amplitude is carried out for three different distributing types of porous truncated conical shells by numerical integration. The frequency-amplitude responses of the system are depicted utilizing the sweeping frequency. The bifurcation diagrams, time series and phase diagrams are utilized to analyze the nonlinear dynamics of the porous truncated conical shell under unified boundary condition. It is found that the multiple solutions high-incidence area is near the 1st primary resonance, and vibration amplitude is dominated by the 1st order primary resonance and the 3rd one. The hardening-spring nature decreases for Type3, Type2 and Type1 successively.
本文旨在研究金属多孔截顶锥壳在厚度方向上承受机械谐波载荷时的非线性振动响应。文章采用了人工弹簧技术来统一边界条件,通过改变弹簧的刚度,可以得到任意经典的实际边界条件。利用汉密尔顿原理,结合 FSDT 和 von-Kármán 几何关系,建立了锥形壳的理论公式。随后,利用广义微分正交法(GDQM),将偏微分方程形式的非线性振动控制方程截断并离散化为常微分方程,这是一个在物理空间而非模态空间描述的高维非线性动力系统。在此基础上,通过数值积分对三种不同分布类型的多孔截顶锥形壳进行了激励频率对振幅影响的分析。利用扫频描绘了系统的频幅响应。利用分岔图、时间序列和相位图来分析统一边界条件下多孔截顶锥形壳的非线性动力学。研究发现,多解高发区位于第 1 次主共振附近,振动振幅以第 1 次主共振和第 3 次主共振为主。第 3 类、第 2 类和第 1 类的硬化弹簧性质依次减弱。
Advantages and design of inerters for isolated storage tanks incorporating soil conditions
Zhao Zhipeng, Hu Xiuyan, Zhang Ruifu, Xie Ming, Liu Songhe
doi:10.1016/j.tws.2023.111356
考虑到土壤条件的隔离储罐灭火器的优点和设计
Inerter-based isolation systems are effective in providing seismic protection for storage tanks. However, the vibration control-oriented mechanism of inerter-based seismic isolation systems on the seismic response of liquid storage tanks remains unclear, with designs limited to rigid base assumptions. Moreover, the objective existence of the soil-structure interaction (SSI) is overlooked. This study contributes to a discovered advantage of the inerter-based isolation system, including the reduction of input energy and precise control of specific or multiple modes of sloshing heights. Furthermore, an advantageous feature-oriented optimal design for storage tanks with an inerter-based isolation system and with the incorporation of soil conditions is proposed in this study. Initially, an analytical model is developed, considering a storage tank with multi-mode sloshing responses and representing SSIs with frequency-dependent stiffness and damping coefficients. Stochastic response analysis is performed, leading to a novel formulation of multi-mode control and an empirical power equation that quantifies the input energy reduction effect. An advantageous feature-oriented optimal design framework, in which the SSI effect, tank geometric parameters, and inerter-based isolation system parameters are implemented, is established through comprehensive parametric analysis. The results demonstrate that the inerter-based isolation system can be intentionally designed to mitigate specific modes of sloshing height, with the inerter effectively reducing the input power of the entire tank. This study emphasizes the importance of incorporating the SSI effect in the seismic analysis and optimal design of inerter-based tanks. Particularly, the inerter-based isolation system designed assuming a rigid base cannot perform as expected due to the SSI effect, significantly resulting in larger seismic responses and energy dissipation burdens. The developed optimal design method guarantees a target base shear force and sloshing height regarding the considered soil condition.
基于惯性体的隔震系统能有效地为储罐提供抗震保护。然而,由于设计局限于刚性基础假设,以振动控制为导向的隔震系统对液体储罐地震响应的影响机制仍不明确。此外,土壤-结构相互作用(SSI)的客观存在也被忽视。这项研究有助于发现基于感应器的隔震系统的优势,包括减少输入能量和精确控制特定或多种模式的坍塌高度。此外,本研究还提出了基于惯性隔离系统并结合土壤条件的储罐优化设计方案。首先,建立了一个分析模型,考虑了具有多模式坍塌响应的储油罐,并用频率相关的刚度和阻尼系数表示 SSI。通过随机响应分析,得出了多模式控制的新表述,以及量化输入能量减少效果的经验功率方程。通过综合参数分析,建立了一个有利的面向特征的优化设计框架,其中包括 SSI 效应、水箱几何参数和基于电抗器的隔离系统参数。结果表明,可以有意识地设计基于电感耦合器的隔离系统,以减轻特定模式的荡高,电感耦合器可有效降低整个水箱的输入功率。这项研究强调了将 SSI 效应纳入基于电抗器的水箱的抗震分析和优化设计的重要性。特别是,由于 SSI 效应,假设刚性基座设计的电抗器隔震系统无法达到预期性能,从而导致更大的地震响应和能量消耗负担。所开发的优化设计方法可确保在所考虑的土壤条件下达到目标基底剪力和坍塌高度。
Thermal vibration analysis of FG-GPLRC doubly curved shells partially resting on Kerr foundation based on higher-order shear deformation theory
Vu Ngoc Viet Hoang, Shi Peng, Toledo Lester, Vu Ha
doi:10.1016/j.tws.2023.111357
基于高阶剪切变形理论的 FG-GPLRC 部分位于克尔地基上的双曲面壳体的热振动分析
In this paper, we present a novel analytical approach for investigating the influence of non-homogeneous Kerr elastic foundations on the nonlinear dynamical characteristics of functionally graded graphene platelets reinforced composite (FG-GPLRC) doubly curved shells. A new aspect of this study is the investigation of various distributions of the Kerr foundation, either centrally within or along the edges of the nanocomposite shells, a model not previously explored. Three distinct distributions of graphene nanoplatelets reinforcement are examined, utilizing the rule of mixtures and the Halpin-Tsai micromechanical model. The theoretical framework is based on Reddy's third-order shear deformation theory. The equations of motion, formulated as partial differential equations, are efficiently resolved through the application of Galerkin's method. The effectiveness of this approach resides in its utilization of integration to tackle the distribution issue of the elastic foundation, all without the need for deploying intricate algorithms. The validity of our proposed method is established through meticulous comparisons with findings from prior literature. Furthermore, this paper delves into the effect of material properties, thermal conditions, boundary conditions, geometrical parameters, and four configurations of the shells on the vibrational responses. Of notable significance is our thorough investigation of the impact of variations in the distributions, stiffness, and geometrical parameters of the elastic foundation on natural frequencies and the nonlinear transient response of these shells, all of which hold great importance in structural design. We present the obtained results systematically in various formats, including tables, 2D and 3D graphs, and contour plots, providing a comprehensive overview of the research outcomes. These findings have profound implications for the field of engineering, contributing to advancements in novel structural designs and their diverse applications.
本文提出了一种新的分析方法,用于研究非均质克尔弹性基础对功能分级石墨烯平板增强复合材料(FG-GPLRC)双曲面壳体非线性动力学特性的影响。这项研究的一个新方面是研究了克尔基础的各种分布,无论是在纳米复合材料壳体的中心还是沿边缘分布,这是以前从未探索过的一种模式。利用混合物法则和 Halpin-Tsai 微机械模型,研究了三种不同的石墨烯纳米片增强分布。理论框架基于 Reddy 的三阶剪切变形理论。运动方程被表述为偏微分方程,通过应用 Galerkin 方法得到有效解决。这种方法的有效性在于它利用积分来解决弹性地基的分布问题,而无需部署复杂的算法。通过与先前文献的研究结果进行细致比较,我们确定了所提方法的有效性。此外,本文还深入探讨了材料特性、热条件、边界条件、几何参数和壳体的四种配置对振动响应的影响。值得注意的是,我们深入研究了弹性地基的分布、刚度和几何参数的变化对自然频率和这些壳体的非线性瞬态响应的影响,所有这些在结构设计中都非常重要。我们以表格、二维和三维图以及等值线图等多种形式系统地展示了所获得的结果,为研究成果提供了一个全面的概览。这些发现对工程领域有着深远的影响,有助于推动新型结构设计及其多样化应用的发展。