今日更新:International Journal of Solids and Structures 1 篇,Journal of the Mechanics and Physics of Solids 1 篇,Thin-Walled Structures 6 篇
Finite strain modelling of shape memory alloys in the logarithmic strain space: A comparative study with other finite strain approaches
Saswata Chattopadhyay, Lucas A. Woodworth, Michael Kaliske
doi:10.1016/j.ijsolstr.2024.112892
对数应变空间中形状记忆合金的有限应变建模:与其他有限应变方法的比较研究
Finite strain models for Shape Memory Alloys (SMAs) offer significant advantages over small strain models in that they excel in their ability to characterise SMA behaviour under large strain and finite rotations while eliminating the inherent assumptions associated with the small strain framework. The paper at hand presents a numerical model for SMAs at finite strain, employing the logarithmic strain measure to obtain an additive split of the total strain into its elastic and inelastic (transformation) parts. Notably, the model maintains the thermodynamic consistency validated using the Clausis-Duhem inequality. Additionally, we compare this model with two other finite strain SMA models employing logarithmic strain measures: a hypoelastic model, which splits the rate of deformation tensor additively, and a hyperelastic model, which decomposes the deformation gradient multiplicatively. The numerical formulation for the three finite strain models is specifically tailored to address superelasticity in SMAs. It is derived from the established small strain model and seamlessly extended into the domain of finite strain framework. Several numerical examples are carried out to showcase the logarithmic strain space approach applied to SMAs and to compare its response with that of the other aforementioned finite strain models in SMAs. The meticulous examination reveals that the logarithmic strain space approach aligns well with the existing finite strain models, demonstrating its effectiveness and compatibility.
形状记忆合金(SMA)的有限应变模型比小应变模型具有显著的优势,因为它们在描述大应变和有限旋转下SMA行为的能力方面表现出色,同时消除了与小应变框架相关的固有假设。本文提出了有限应变下sma的数值模型,采用对数应变测度得到了总应变在弹性和非弹性(转换)部分的加性分裂。值得注意的是,该模型保持了使用Clausis-Duhem不等式验证的热力学一致性。此外,我们将该模型与另外两种采用对数应变测量的有限应变SMA模型进行了比较:一种是将变形张量速率相加的低弹性模型,另一种是将变形梯度相乘分解的超弹性模型。三种有限应变模型的数值公式是专门为解决sma中的超弹性而量身定制的。它是从已有的小应变模型中衍生出来的,并无缝地扩展到有限应变框架领域。通过几个数值算例,展示了对数应变空间方法在sma中的应用,并将其与上述其他有限应变模型的响应进行了比较。结果表明,对数应变空间方法与现有的有限应变模型吻合良好,证明了其有效性和兼容性。
Phase-field model for 2D cohesive-frictional shear fracture: An energetic formulation
Ye Feng, Francesco Freddi, Jie Li, Yu E. Ma
doi:10.1016/j.jmps.2024.105687
二维黏结-摩擦剪切断裂的相场模型:一个能量公式
This paper presents a phase-field model for cohesive-frictional shear fracture. The model is derived based on two energetic principles: the energy conservation law and a variational inequality of virtual work that serves as a stability condition. We show that all the governing equations for frictional fracture can be obtained from the above two principles, including the equilibrium condition, the phase-field evolution law and, most importantly, the yield function and flow rule for the plasticity-like frictional slip. The information of crack direction is naturally included in the flow rule. Theoretical and numerical results show that the proposed model is faithfully consistent with the Mohr–Coulomb theory of frictional failure in terms of the crack nucleation stress and direction. In addition, the presented phase-field model has an explicit frictional cohesive law.
本文提出了黏结-摩擦剪切断裂的相场模型。该模型基于两个能量原理:能量守恒定律和作为稳定条件的虚功的变分不等式。结果表明,上述两种原理均可得到摩擦断裂的控制方程,包括平衡条件、相场演化规律,以及最重要的类塑性摩擦滑移的屈服函数和流动规律。裂纹方向信息自然包含在流动规律中。理论和数值结果表明,该模型在裂纹形核应力和方向上与Mohr-Coulomb摩擦破坏理论完全一致。此外,所提出的相场模型具有明确的摩擦内聚规律。
Three-dimensional hygro-thermo-mechanical bending analysis of anisotropic skewed parallelogram plates on a tri-parameter foundation using a wavelet method
Qiang Yu, Junfeng Xiao, Hang Xu
doi:10.1016/j.tws.2024.112006
基于三参数基础的各向异性倾斜平行四边形板三维水热力学弯曲分析
In the paper, a brand-new three-dimensional hygro-thermo-mechanical bending model of anisotropic skewed parallelogram plates with extreme skew angle in large deformation supported by a tri-parameter nonlinear elastic foundation is proposed. By investigating the mutual coupled interaction of hygrothermal effects between in-plane distribution and thickness variation, nine kinds of spatially analytical hygrothermal fields in parallelogram domain are established by analyzing the Dirichlet, Neumann and Robin thermal boundary conditions of sinusoidally induced heat conduction at top and bottom surfaces. With coordinate transformation in oblique system considering the Von Kármán membrane strains, the highly coupled and strongly nonlinear governing partial differential equations have been derived. A wavelet solving procedure has been developed with the convergence process validated and precision of obtained solutions verified in good accordance with published results. Parametric studies have been carried out to investigate the large-deflection behavior of simply supported or clamped skew plates on Winkler-Pasternak foundation under combined mechanical and hygrothermal loads. The influence of skew angle, material orthotropy and foundation contact nonlinearity is examined, which reveals the geometrically nonlinear responses of plates are highly affected by large oblique angle, principle orientation of material orthotropy and foundation parameters.
本文提出了三参数非线性弹性地基支撑的各向异性极斜角平行四边形板在大变形条件下的全新三维水热力学弯曲模型。通过对上下表面正弦诱导热传导的Dirichlet、Neumann和Robin热边界条件的分析,建立了平行四边形域中9种空间解析型热场,研究了平面内分布与厚度变化之间的热效应相互耦合作用。在考虑Von Kármán膜应变的斜坐标系下进行坐标变换,导出了高耦合、强非线性的控制偏微分方程。提出了一种小波求解方法,并验证了该方法的收敛性,得到的解的精度与已发表的结果一致。对温克勒-帕斯捷尔纳克基础上简支或夹紧斜板在机械和湿热联合荷载作用下的大挠度行为进行了参数化研究。分析了斜倾角、材料各向异性和基础接触非线性对板的几何非线性响应的影响,表明大斜倾角、材料各向异性主取向和基础参数对板的几何非线性响应影响较大。
Meshing behavior assessment methods for hybrid metal-composite gears with anisotropic and quasi-isotropic webs
Zhou Sun, Siyu Chen, Jinyuan Tang, Zehua Hu, Xuan Tao, Duncai Lei, Hongtao Dong
doi:10.1016/j.tws.2024.112031
具有各向异性和准各向同性腹板的混合金属-复合齿轮啮合行为评估方法
Thin-web structures are the primary strategy for lightweight gears in the aerospace and automotive fields, but current research mainly focuses on metal thin web, lacking understanding of the application of anisotropic and quasi-isotropic composite thin-web gears. Focusing on accurate and efficient calculations of mesh stiffness and load sharing ratio, this work develops a unified numerical analysis method to assess the meshing behavior of the two hybrid metal-composite gears. Multi-scale numerical prediction methods for elastic properties of anisotropic composite and homogeneous laminated webs are established, and two tooth-loading deformation calculation methods for metal-composite-metal gear bodies with different web widths are developed separately. A numerical analysis method is proposed by unifying the iterative calculation process of the two hybrid gears through deformation coordination relationships, which is also applicable to full metal gears. Finally, extensive comparisons with the finite element method (FEM) and existing numerical method verify the proposed analytical method (PAM). The investigation results reveal the impact of replacing full metal gears with these two hybrid gears on the meshing behavior and further elucidate the advantages of using composite webs for micro and macro parameters design in adjusting the mass and stiffness and reducing mesh stiffness fluctuations. This work provides a new analytical method for the structural design and performance assessment of lightweight hybrid metal-composite gear systems.
薄腹板结构是航空航天和汽车领域轻量化齿轮的主要策略,但目前的研究主要集中在金属薄腹板上,缺乏对各向异性和准各向同性复合薄腹板齿轮应用的了解。着眼于准确、高效地计算啮合刚度和载荷分担比,本文开发了一种统一的数值分析方法来评估两个金属-复合材料混合齿轮的啮合性能。建立了各向异性复合材料和均匀层合腹板弹性性能的多尺度数值预测方法,分别开发了两种不同腹板宽度的金属-复合-金属齿轮体齿载变形计算方法。通过变形协调关系统一了两种混合齿轮的迭代计算过程,提出了一种数值分析方法,该方法同样适用于全金属齿轮。最后,通过与有限元法(FEM)和现有数值方法的比较,验证了所提出的解析法(PAM)的有效性。研究结果揭示了用这两种混合齿轮代替全金属齿轮对啮合性能的影响,进一步阐明了采用复合腹板进行微观和宏观参数设计在调节质量和刚度、减小啮合刚度波动方面的优势。为轻量化金属复合材料混合齿轮系统的结构设计和性能评价提供了一种新的分析方法。
Design and Analysis of a Solid Surface Deployable Antenna Mechanism Based on Flasher Rigid Origami
Dake Tian, Xihua Yang, Lu Jin, Zuwei Shi, Hongwei Guo, Rongqiang Liu
doi:10.1016/j.tws.2024.112033
基于Flasher刚性折纸的固体表面可展开天线机构设计与分析
This study proposes a mechanism for solid surface deployable antennas based on flasher rigid origami. The mechanism scheme design and degree-of-freedom analysis were conducted utilizing a Kirigami release constraint strategy. Subsequently, a spatial geometric model of the key points was established incorporating the folding and unfolding characteristics and geometric relationships within the mechanism. Furthermore, a comprehensive 3D model of the antenna was developed by determining the hinge locations, geometric parameters, and driving mechanism, followed by a kinematic simulation analysis. Finally, a prototype was constructed, and a microgravity deployment experiment was conducted to verify the feasibility of the mechanism.
本研究提出了一种基于闪光刚性折纸的固体表面可展开天线机制。采用Kirigami释放约束策略进行了机构方案设计和自由度分析。随后,结合机构内部的折叠展开特性和几何关系,建立了关键点的空间几何模型。通过确定天线的铰链位置、几何参数和驱动机构,建立了天线的三维模型,并进行了运动学仿真分析。最后,搭建了原型机,并进行了微重力展开实验,验证了该机构的可行性。
Anti-plane dynamic response characteristics of a semi-infinite plate with cylindrical hole defect
Fan Zhiyu, Qi Hui, Zhang Yufeng, Wu Hao, Chu Fuqing, Guo Jing
doi:10.1016/j.tws.2024.112038
半无限圆孔缺陷板的反平面动力响应特性
The semi-infinite thin plate structure, widely used in aerospace industry devices and spliced functional composites, fails to meet the dynamic response performance and stability requirements due to the dynamic stress concentration or displacement mutation caused by the structure boundary and internal defect under specific external dynamic loads. This study has established an analytical method for the dynamic response characteristics in steady-state frequency-domain and transient time-domain of a semi-infinite thin plate with a cylindrical hole under the excitation of external anti-plane dynamic loads. Based on the wave function expansion method, cumulative mirroring method, and complex variable function method, the distribution of dynamic stress concentration and displacement amplitude under steady-state anti-plane excitation has been given. Based on the Fourier transform and inverse Fourier transform, the analysis of dynamic response behavior under transient anti-plane excitation has been given. Numerical results indicate that the coupled scattered waves generated by multiple boundaries will cancel and amplify the dynamic stress and displacement amplitude within the plate under different parameter combinations, leading to the dynamic stress concentration and displacement mutation of the structure. Therefore, reasonable structural design optimization will benefit the dynamic response performance and stability requirements of the structure.
广泛应用于航空航天工业器件和拼接功能复合材料的半无限薄板结构,在特定的外部动载荷作用下,由于结构边界和内部缺陷引起的动应力集中或位移突变,不能满足动态响应性能和稳定性要求。建立了外反平面动载荷作用下带圆柱孔的半无限薄板在稳态频域和瞬态时域的动态响应特性分析方法。基于波函数展开法、累积镜像法和复变函数法,给出了稳态反平面激励下动应力集中和位移幅值的分布。基于傅里叶变换和傅里叶反变换,分析了瞬态反平面激励下的动力响应特性。数值结果表明,在不同参数组合下,由多个边界产生的耦合散射波会抵消和放大板内的动应力和位移幅值,导致结构的动应力集中和位移突变。因此,合理的结构设计优化有利于结构的动力响应性能和稳定性要求。
Free vibration analysis of pre-twisted rotating dovetailed blade under the flexible connection with macro-micro rough contact topography
Hehe Kang, Zhi-Min Li, Tao Liu, Wei Yuan, Jianping Jing
doi:10.1016/j.tws.2024.112039
宏微粗糙接触地形柔性连接下预扭旋转燕尾叶片自由振动分析
The dynamic characteristic of the dovetailed blade plays a key role in the performance and service life of the whole aero-engine. Due to the current manufacturing accuracy and process, the macro-micro contact topography is random and various, which causes the change of the contact response in the blade root as well as the vibration of the blade body. In this paper, a new dynamic model of the pre-twisted rotating dovetailed blade under the flexible connection is established to investigate the free vibration of the blade with macro-micro rough contact topography. First, the elastic boundary of the blade root is quantified by the connection stiffness deduced from the rough contact theory. The governing equation of the blade is formulated by the thin shell theory, and the orthogonal polynomials are employed as the admissible displacement function to calculate the natural frequency though the Ritz method. Then, the effectiveness of the proposed model is validated by comparing it with the theoretical and experimental data. Finally, the influences of the pre-twisted angle, the rotational speed, the macroscopic geometrical deviation, and microscopic topography parameters on free vibration of the blades are investigated in detail. The results show that the natural frequencies have the crossover phenomenon as the parameters vary. The macro-micro topography parameters of the contact interface have a stronger ability to influence the frequency when the rotating speed is low than the high rotating speed. The presented work builds a bridge between the vibration characteristic of the blade body and the macro-micro rough contact topography of the dovetailed joint, which is very meaningful to guide the design of the aero-engine.
燕尾叶片的动态特性对整个航空发动机的性能和寿命起着至关重要的作用。由于目前的制造精度和工艺,宏观微观接触形貌是随机的、多样的,这导致了叶根接触响应的变化以及叶体的振动。建立了柔性连接下预扭旋转燕尾叶片的动力学模型,研究了具有宏微观粗糙接触形貌的预扭旋转燕尾叶片的自由振动问题。首先,利用粗糙接触理论推导出的连接刚度对叶根的弹性边界进行量化;采用薄壳理论建立了叶片的控制方程,采用正交多项式作为允许位移函数,采用里兹法计算叶片的固有频率。然后,通过与理论和实验数据的比较,验证了所提模型的有效性。最后,详细分析了预扭角、转速、宏观几何偏差和微观形貌参数对叶片自由振动的影响。结果表明,随着参数的变化,固有频率存在交叉现象。转速较低时,接触界面的宏微观形貌参数对频率的影响能力强于转速较高时。本文所做的工作在叶体振动特性与燕尾接头宏微观粗糙接触形貌之间架起了一座桥梁,对指导航空发动机的设计具有重要意义。
Static Mechanical Properties and Failure Behaviors of Self-Piercing Riveted Joints in Aluminum Alloy 5A06 after Aging
Kai Ye, Zhao Lun, Zeshan Abbas, Chengwang Li, Gaoyu Liu, Le Lei, Jiehao Lu, Md Shafiqul Islam
doi:10.1016/j.tws.2024.112041
5A06铝合金自穿铆接接头时效后的静态力学性能及失效行为
This paper conducts an investigation on the static mechanical properties and failure behavior of self-piercing riveted joints in aluminum alloy 5A06 after being subjected to the aging process. The study involves three distinct categories of joint specimens: original specimens, 1-year aged specimens and 1-year aged specimens that have been additionally heat-treated at 200°C. The research findings affirm that strain aging is responsible for a reduction in the peak strength of the joints. Furthermore, the weakest failure chain within the self-piercing riveted joint shifts towards the upper sheet due to a more significant reduction in internal stress experienced by the upper plate. This leads to a failure model characterized by upper sheet pull-off. Through Weibull distribution analysis, it has been established that the 5% lower limit value for the strength of the SPR joint experiences an 86% decline following 1-year aging. In practical terms, this means that for a vehicle structure with 7,000 riveting points will lose an overall structural strength equivalent to the initial strength of 1,000 riveting points within one year.
研究了5A06铝合金自穿铆接接头在时效过程中的静态力学性能和失效行为。本研究涉及三种不同类型的关节试件:原始试件、1年时效试件和经200℃额外热处理的1年时效试件。研究结果证实,应变老化是导致接头峰值强度降低的主要原因。此外,自穿铆接接头内最弱的破坏链向上板移动,因为上板所经历的内应力更显著地减少。这导致了一种破坏模式,其特征是上部板的拉脱。通过Weibull分布分析可知,SPR接头强度下限为5%,时效1年后强度下降86%。实际上,这意味着对于具有7,000个铆接点的车辆结构,在一年内将失去相当于1,000个铆接点的初始强度的整体结构强度。