自卸车后桥壳有限元应力计算

通过建立后桥壳有限元力学计算模型，确定了计算中的边界约束条件，并对原模型、加筋模型两种有限元模型七种工况的所有结点进行了应力分析与比较。应力计算结果为该车的改进设计和结构优化提供了理论依据。     

结构件焊缝弹塑性强度有限元分析

对有缺陷焊缝弹塑性分析的理论研究与推导．分析有缺陷焊缝的承载能力,给出结构的安全系数。     

汽车后桥有限元疲劳寿命分析

利用Unigraphics软件,建立了汽车后桥三维CAD模型,利用UG的Structures模块对后桥的应力分布及疲劳寿命进行了有限元分析,得出了该构件的应力及疲劳寿命分布图,并提出了提高疲劳寿命的改进方案.     

随机加载下缺口局部应力应变的弹塑性有限元计算

根据材料在塑性变形后引起的各向异性和Bauschinger效应,利用Jhansale模型原理,对缺口件在随机加载下的缺口根部的局部应力和应变进行弹塑性有限元分析,有限元分析采用了随动强化模型,并考虑材料瞬态局部应力应变的响应特性,最后,将本文有限元的局部应力应变历程分析结果与工程上常用的Neuber法进行了比较。     

自卸车后桥壳有限元应力计算

通过建立后桥壳有限元力学计算模型,确定了计算中的边界约束条件,并对原模型、加筋模型两种有限元模型七种工况的所有结点进行了应力分析与比较.应力计算结果为该车的改进设计和结构优化提供了理论依据.     

胶焊接头的三维弹塑性应力分析

采用三维弹塑性有限元方法,数值分析了胶焊搭接接头的应力分布,并与点焊接头、胶接接头的应力分布情况相比较。结果表明,胶焊接头搭接区中应力分布均匀,其焊点内部不存在点焊接头焊点中所具有的高应力,消除了点焊接头中焊点边缘处的应力集中。胶焊接头的应力分布特征与胶接接头十分相似。由应力分析预测的接头强度与已有的试验结果一致。     

宏观力学性能不均匀裂纹体弹塑性断裂行为的有限元分析

根据实际工程结构中存在的力学性能非均匀性的特点,对中—硬—软、软—中—硬、硬—软—中三种典型非均匀裂纹体进行了有限元分析,研究了夹层宽度对 J 积分、裂纹尖端张开位移(CTOD)、裂纹嘴张开位移(CMOD)的影响.     

汽车后桥壳工艺分析及解决方案

通过对汽车后桥壳的工艺分析,介绍了汽车焊接式后桥在组合机床上的常规工艺流程,并针对用户的一些特殊要求,提出了解决方案,总结出一条规范可靠的加工工艺方案。     

SAP5程序中的弹塑性有限元初应力变模量模块化方法与结构绘图

概述了弹塑性有限元分析的一种新算法——初应力变模量法。给出了模块化程序与SAP5程序的联接方案,并利用西德Siemens-7570.C大型计算机现有绘图软件,完成结构弹性、弹塑性变形图的缩放旋转,局部修正、汉字信息显示以及平面应力、应变彩色剖面分布线的绘制。与现有大型程序中弹、塑性有限元增量算法比较,在SPA5程序中引入新算法可显著提高计算效率和收敛速度。     

Experimental verification of rate-dependent elastoplastic analogy friction model and its application to FE analysis

When two solid bodies in contact slide slowly past each other without lubrication, an intermittent vibration phenomenon might be observed. Such rate-dependent frictional behaviors are referred to as stick–slip motions, and such motions can impair the stability of machines and structures. The aim of this study is to propose a numerical approach for analyzing stick–slip motion; the approach is based on the finite element method implemented using a rate-dependent friction model. First, we demonstrate the capability of the rate-dependent friction model by comparing its results with experimental results obtained under various material and dynamic conditions. Then, a simple finite element analysis of rate-dependent frictional sliding behavior, including stick–slip motion, is carried out to examine the effect of the material and geometric properties and boundary conditions on the numerical results. The present numerical approach can consider not only the properties of friction and materials but also variations in boundary conditions.     

汽车半轴套管失效载荷数值模拟

本文对我国生产的一种汽车半轴套管进行了大位移、大应变弹塑性有限元模拟,求得了加载点的栽荷-位移曲线、最大应力点的弹塑性应变-载荷曲线、危险截面的弹塑性应力-载荷曲线、危险截面达到全面屈服时的失效载荷等,为汽车半轴套管的强度评价及疲劳寿命估算提供了有关数据.     

辊式矫直过程应力演变及其对反弯特性的影响

通过对辊式矫直连续反弯过程中的应力遗传与反弯特性的耦合关系的研究,论证在弹塑性连续反弯过程的分析中考虑截面弯曲历史的必要性;并应用弹塑性理论的基本理论,建立考虑变形历史时求解多次反弯过程参数的数值解法,进而详细研究小变形矫直过程的应力遗传规律及其对弯矩—曲率(M-C)关系曲线的影响等。研究发现变形历史对条材断面的反弯特性具有不可忽略的影响,反弯特性的差异使同一工艺条件下不同截面的M-C曲线无法收敛。矫直过程中,具有不同初始曲率的截面在通过同一矫直设备后会经历不同的变形历史,从而产生不同反弯特性,最终导致无法实现残留曲率范围随反弯次数的增加而逐步减小的预期。这从理论上解释了小变形原则在生产现场应用效果不佳的原因。     

Numerical analysis of stick-slip instability by a rate-dependent elastoplastic formulation for friction

In various fields of engineering, it is important to clarify friction-induced vibration, such as stick-slip motion, for a wide range of scales from microscopic elements to continental plates. In the present study, we apply a rate- and state-dependent friction model [30] (Hashiguchi and Ozaki, 2008), which can rationally describe the reciprocal transition between the static friction and the kinetic friction by a unified formulation, to the simulation of stick-slip instability for a one-degree-of-freedom spring-mass system under various conditions. It is verified that the various basic experimental findings on stick-slip motion can be pertinently described by the present approach. Moreover, the effect of the dynamic characteristics of the system, such as the mass, stiffness and driving velocity, is discussed, and parameters prescribing the rate of reciprocal transition of static-kinetic frictions and the preliminary microscopic sliding on the instability of the stick-slip motion are also discussed.     

基于ANSYS主减速器壳应力及模态分析

主减速器壳在工作过程中常受到多种载荷的共同作用,工况复杂。基于有限元理论,运用ANSYS软件对主减速器壳进行了数值分析,得到了主减速器壳的机械应力分布规律,同时对其进行了模态分析,得到了主减速器壳的固有频率等。分析结果可为主减速器壳设计提供理论依据。     

汽车变速器模态分析及振动噪声测试实验研究

在PRO/E环境下建立SG13 5汽车变速器的 3D实体模型 ,应用I DEAS对变速器箱体进行动力学有限元分析 ,获得动力学参数。设计实验方案 ,测试和分析了箱体不同部位的振动与噪声信号 ,为变速器的减振降噪优化设计奠定了基础。     

基于ANSYS的汽车发动机连杆有限元分析

采用ANSYS软件建立汽车连杆三维模型，并通过ANSYS软件对连杆进行应力分析，得到变形过程中的应力场、应变场分布，为进行发动机连杆的优化设计建立基础。     

An adjoint variable method for design sensitivity analysis of elastoplastic structures

Design sensitivity analysis of structural problems obeying an elastoplastic material behavior is developed using adjoint variable method. An elastoplastic constitutive equation with yield surface and kinematic hardening is considered to describe the material behavior. The traditional incremental procedure and its design variation need special treatments in order to predict the discontinuity of the structural response sensitivity because the contribution from the design sensitivity at the material transition point is lost during the calculation. In this study, discontinuities of the design variations at the material transition points are alleviated in the adjoint variable method. Analytical and numerical examples are used not only to demonstrate the developed sensitivity procedure but also to gain insights of numerical implementation for the design sensitivity analysis of the elastoplastic structure based on the adjoint variable method. The comparisons between adjoint variable and direct variation methods are also discussed.     

Modelling the evolution of residual stresses during tensile testing of elastoplastic wires subjected to a previous bending operation

During coiling operations high residual stresses are frequently developed in steel wire. In this paper the stress distribution in wires during coiling, unwinding and subsequent tensile testing is modelled for numerous bending degrees, assuming perfect Voce plastic deformation and linear elastic behaviour. The influence of such residual stresses on the observed tensile test data can be deduced. It is shown that coiling with spool radii as used today industrially can lead to measurement of wire properties deviating significantly from the “true” properties of a properly coiled wire. Also, a method is proposed to deduce the original flow behaviour of coiled samples from tensile test curves, hence filtering the effect of the residual stresses.     

On the rotating elastic–plastic solid disks of variable thickness having concave profiles

In this paper, an analytical solution for the elastic–plastic stress distribution in rotating variable thickness solid disks is presented. The analysis is based on Tresca's yield criterion, its associated flow rule and linear strain hardening material behavior. It is shown that depending on the shape of the disk profile, the radial stress in the central region may exceed the circumferential stress. The plastic zone which develops away from the axis of the disk consists of three annular regions governed by different mathematical forms of the yield criterion. The propagation of these plastic regions with increasing angular velocity is obtained together with the distributions of stresses and deformations in nondimensional forms.