检索结果-南通市图书馆

Elastic stress fields caused by a dislocation in Ge_xSi_(1-x)/Si film-substrate system

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2014年第6期57卷 1078-1089页

作者： wang huyi YU Yong YAN ShunPing Institute of Systems Engineering China Academy of Engineering Physics

The elastic stress fields caused by a dislocation in GexSil~ epitaxial layer on Si substrate are investigated in this work. Based on the previous results in an anisotropic bimaterial system, the image method is further developed to determine the stress field of a dislocation in the film-substrate system under coupled condition. The film-substrate system is firstly transformed into a bimaterial system by distributing image dislocation densities on the position of the free surface. Then, the unknown image dis- location densities are solved by using boundary conditions, i.e., traction free conditions on the free surface. Numerical simula- tion focuses on the Ge0.1Si0.9/Si film-substrate system. The effects of layer thickness, position of the dislocation and crystallo- graphic orientation on the stress fields are discussed. Results reveal that both the stresses σxx,σxz at the free surface and the stress o-σx, σyy, σyz on the interface are influenced by the layer thickness, but the former is stronger. In contrast to the weak de- pendence of stress field on the crystallographic orientation the stress field was strongly affected by dislocation position. The stress fields both in the film-substrate system and bimaterial system are plotted.

关键词： elastic dislocation anisotropic image method couple

Stress fields caused by a dislocation in an anisotropic 3-layer system

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2011年第3期54卷 542-551页

作者： wang huyi YIN YiHui YU ShaoRong Institute of Structural Mechanics China Academy of Engineering Physics Mianyang 621900 China

We investigated the stress fields caused by a dislocation in an anisotropic 3-layer system. Based on the image method, the original 3-layer system is firstly decomposed into three infinite homogenous systems. The image dislocation densities used as unknowns are then strategically distributed in order to satisfy the boundary conditions. The resulting governing equations are singular Cauchy integral ones. Removing the singular terms yields non-linear Fredhom integral equations of the second kind. The obtained stress fields satisfy the boundary conditions, i.e., the traction free condition on the free surface and continuous conditions across the interfaces. Also, a comparison with previous results is made and good agreement is achieved. Numerical investigations show that under the plain strain condition, layer thickness and dislocation position play stronger roles in the stress fields than crystallographic orientation, and these effects more significantly affect the stress fields caused by an edge dislocation than by a screw dislocation.

关键词： stress field dislocation anisotropic 3-layer system

A CONSTITUTIVE MODEL FOR TRANSFORMATION, REORIENTATION AND PLASTIC DEFORMATION OF SHAPE MEMORY ALLOYS

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2012年第3期25卷 285-298页

作者： Xianghe Peng Bin Chen Xiang Chen Jun wang huyi wang Department of Engineering Mechanics Chongqing UniversityChongqing 400044China State Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing UniversityChongqing 400044China China Academy of Engineering Physics Mianyang 621900China

A constitutive model is developed for the transformation, reorientation and plastic deformation of shape memory alloys （SMAs）. It is based on the concept that an SMA is a mixture composed of austenite and martensite, the volume fraction of each phase is transformable with the change of applied thermal-mechanical loading, and the constitutive behavior of the SMA is the combination of the individual behavior of its two phases. The deformation of the martensite is separated into elastic, thermal, reorientation and plastic parts, and that of the austenite is separated into elastic, thermal and plastic parts. Making use of the Tanaka＇s transformation rule modified by taking into account the effect of plastic deformation, the constitutive model of the SMA is obtained. The ferroelasticity, pseudoelastieity and shape memory effect of SMA Au-47.5 at.%Cd, and the pseudoelasticity and shape memory effect as well as plastic deformation and its effect of an NiTi SMA, are analyzed and compared with experimental results.

关键词： shape memory alloys two-phase mixture transformation reorientation plasticity,constitutive model

NUMERICAL SIMULATION OF QUASI-STATIC COMPRESSION ON A COMPLEX RUBBER FOAM

在线全文

学校读者我要写书评

暂无评论

NUMERICAL SIMULATION OF QUASI-STATIC COMPRESSION ON A COMPLE...

Gamma radiation induced compressive response of silicon rubber foam: Experiments and modeling

中国力学大会-2017暨庆祝中国力学学会成立60周年大会

作者： huyi wang Wenjun Hu Fengpeng Zhao Institute of Systems Engineering CAEP

A complex rubber foam under quasi-static compression is numerically simulated by finite element method(FEM). Uniaxial compression is firstly tested on the base material. The obtained test data are used to calculate the parameters for the phenomenological constitutive model. Then computerized tomography(CT) technique is utilized to reconstruct the real complex foam structure. After implanting the phenomenological constitutive model into ABAQUS, simulation is done on the foam structure under quasi-static compression. The present FEM results are compared with those obtained by the multi-scale simulation and the experiments, and good agreements are achieved.

关键词： complex rubber foam quasi-static compression

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Gamma radiation induced compressive response of silicon rubb...

形状记忆合金单晶细观本构关系的一种相变动力学模型及算法

中国力学大会（CCTAM2019）

作者： huyi wang Yong Qiu Wenjun Hu Yongmei Chen Institute of Systems Engineering CAEP Shock and Vibration of Engineering Materials and Structures Key Laboratory of Sichuan Province

Utilizing the experimental and numerical approaches, the gamma radiation induced compressive response of the silicon rubber foams under quasi-static compression are investigated. In the experimental research, the quasi-static compression is carried out on the samples of the silicon rubber and the silicon rubber foam. Both the samples are next exposed to the gamma radiation dose of 500 kGy with the dose rate of 100 Gy/min. The data comparison reveals that the gamma radiation hardens the samples. As the nominal strain is 20%, the compressive stresses of the rubber and the rubber foam both increase over 5 times after the gamma radiation. In the present work, a multi-scale method combined with finite element method is developed to numerically predict the compressive response of the silicon rubber foam before and after the gamma radiation. The micro-scale model is constructed according to the real micro-structures of the silicon rubber foam. Its stress and strain relationship is then simulated by using the phenomenological constitutive models, which are setup based on the testing data of the silicon rubber before and after the gamma radiation. Simulation results show that the gamma radiation strongly affect the compressive response of the micro-scale model. Based on the mechanical behaviors of the micro-scale model, the macro-scale models of the silicon rubber foam are investigated numerically. Results also reveal that the gamma radiation obviously increases the compressive stress. The obtained simulation results agree with the testing data well, which verifies the developed method. The present work develops a new method to predict the gamma radiation effects on mechanical properties of rubber foams.

关键词： gamma radiation compressed rubber foams quasi-static

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

固体力学学报 2012年第1期33卷 8-16页

作者：陈斌彭向和王军王沪毅重庆大学工程力学系重庆大学煤矿灾害动力学及控制国家重点实验室重庆400044 中国工程物理研究院总体工程研究所绵阳621900

形状记忆合金是由马氏体相和奥氏体相组成的非均质材料,热力载荷及相变不可避免地在材料中引起残余微应力场,它与外界驱动力的叠加可能导致低应力水平下发生马氏体相变或逆相变.论文假设马氏体相变及逆相变的驱动力是马氏体体积分数的... 详细信息

形状记忆合金是由马氏体相和奥氏体相组成的非均质材料,热力载荷及相变不可避免地在材料中引起残余微应力场,它与外界驱动力的叠加可能导致低应力水平下发生马氏体相变或逆相变.论文假设马氏体相变及逆相变的驱动力是马氏体体积分数的连续函数,发展了形状记忆合金伪弹性的本构描述及相应的数值分析方法.分析表明,所发展的方法与理想相变模型间的误差远小于已有工作中引入的容许误差.对形状记忆合金单晶伪弹性响应的计算结果与试验结果或已有模型计算结果的比较表明所发展的方法具有较高的精度.此外,所发展的方法具有明晰的物理背景,且无需对每个变体的相变发生与否及其方向进行判断,简化了计算过程,提高了计算效率和收敛性.

关键词：形状记忆合金马氏体变体相变伪弹性本构关系

硅橡胶泡沫材料与刚性面准静态摩擦接触数值分析研究

在线全文

学校读者我要写书评

暂无评论

机械强度 2018年第6期40卷 1490-1494页

作者：王沪毅胡文军邱勇中国工程物理研究院总体工程研究所绵阳621999

基于有限元方法模拟研究硅橡胶泡沫材料与刚性接触面在准静态摩擦接触过程中的力学性能。基于多尺度方法建立与实际泡孔结构相符的细观模型-单胞泡孔模型。考虑泡孔壁之间摩擦因素,计算获得细观模型的力学性能。将细观模型性能通过数据... 详细信息

基于有限元方法模拟研究硅橡胶泡沫材料与刚性接触面在准静态摩擦接触过程中的力学性能。基于多尺度方法建立与实际泡孔结构相符的细观模型-单胞泡孔模型。考虑泡孔壁之间摩擦因素,计算获得细观模型的力学性能。将细观模型性能通过数据传递机制植入宏观模型,据此模拟研究硅橡胶泡沫材料与刚性加载面相互作用时的压缩载荷和结构变形情况,并讨论界面摩擦因数对该材料力学性能的影响。模拟结果表明,摩擦因数对硅橡胶泡沫材料的准静态单轴压缩力学性能影响较小,且所得模拟结果与实验结果吻合良好。

关键词：有限元硅橡胶泡沫材料刚性接触面摩擦接触多尺度

数值模拟中细观泡孔构型对硅橡胶泡沫材料力学性能的影响

在线全文

学校读者我要写书评

暂无评论

材料科学与工程学报 2019年第1期37卷 112-116页

作者：王沪毅胡文军尹益辉中国工程物理研究院总体工程研究所四川绵阳621999

基于有限元方法模拟准静态单轴压缩过程中硅橡胶泡沫材料的力学响应,并基于硅橡胶泡沫材料的泡孔特征,建立具有均匀分布且球孔尺寸一致的周期性物理模型,采用多尺度结合有限元数值方法进行模拟。根据已有的实验数据,拟合了实体硅橡胶材... 详细信息

基于有限元方法模拟准静态单轴压缩过程中硅橡胶泡沫材料的力学响应,并基于硅橡胶泡沫材料的泡孔特征,建立具有均匀分布且球孔尺寸一致的周期性物理模型,采用多尺度结合有限元数值方法进行模拟。根据已有的实验数据,拟合了实体硅橡胶材料的唯像本构方程。多尺度模拟研究中,建立了四种不同的细观泡孔单元,模拟了四种细观泡孔单元在准静态单轴压缩条件下的力学响应。模拟结果表明,四种细观泡孔单元均具有典型的超弹性力学特性,不同泡孔构型能造成细观模型力学响应的显著差异,四种细观泡孔单元中应力最大差值超过300%。细观模型的力学性能通过数据传递机制传输到均匀化的宏观模型后,采用有限元方法对宏观模型进行数值模拟。结果表明:宏观模型具有典型的超弹性力学特性,不同的细观泡孔构型能导致宏观模型力学响应的显著差异,其中应力最大差值超过300%。

关键词：有限元准静态单轴压缩硅橡胶泡沫多尺度模拟

在线全文

学校读者我要写书评

暂无评论

异氟烷抑制星形胶质细胞葡萄糖摄取