Influence of Temperature and Strain Rate on the Mechanical Properties of B83 Babbitt with Different Structures

We experimentally establish the dependences of the mechanical characteristics of the B83 babbitt (yield limit, ultimate strength, relative elongation, the coefficient of strain-rate sensitivity, yield stress, and microhardness) with different types of structure on the strain rate and temperature.     

碳纳米管力学性能分析的分子结构有限元模型

基于分子结构力学理论,将C—C共价键等效比拟为空间梁单元,利用ANSYS的二次开发工具APDL语言编程创建能够恰当模拟碳纳米管原子间相互作用势的分子结构有限元模型,应用该模型详细研究碳纳米管在简单拉伸和纯扭转时的力学性能及其尺度效应,即手性角和管径变化对碳纳米管杨氏模量、泊松比和剪切模量的定量影响。计算结果表明,杨氏模量和剪切模量与大部分相关文献的结果吻合,但泊松比的数值结果和尺度依赖性规律在国内外文献中尚未获得统一观点,且在弹性模量、泊松比和剪切模量之间未发现明确的定量关系。     

Computer Experiment on Deformation of Nanocrystals of the Chromium-Niobium System. Part 2. Mechanical Properties

Molecular-dynamic simulation of the process of stretching of chromium and niobium nanocrystals and chromium-niobium bicrystals was performed to a pair-potential approximation. The authors obtained and analyzed the dependences of the potential energy, the number of pair interactions, work of deformation, stress, reduction in the cross-sectional area, and Poissons ratio on the strain with various orientations of nanocrystals with respect to the tensile force. They calculated the characteristics of elasticity, yielding, and strength of nanocrystals.__________Translated from Problemy Prochnosti, No. 2, pp. 5 – 18, March – April, 2005     

受冲板壳结构的弹塑性力学特性分析

采用基于随动坐标系的 4节点假设应变场壳单元及显式有限元方法分析受冲板壳结构的弹塑性力学特性。材料模型采用弹塑性等向强化模型 ,接触搜寻采用一体化接触搜寻方法 ,接触力由罚参数法计算 ,算例表明 :该方法简明、直观、快捷、方便     

Local Assessment Concepts for the Structural Durability of Complex Loaded Components

As fatigue damage is a local phenomenon, the design of components must put emphasis on local supportable stress/strain values. In critical areas of components, because of local stress/strain concentrations and appertaining stress/strain gradients, much higher local values can be allowed than the usual design data obtained with unnotched specimens. Only the knowledge of these local values can realize light‐weight design exploiting the material limits. Using component examples like pressure vessels, gears and wheel‐hub assemblies, different variants of local concepts, i.e. strain and stress based methods, are presented for assessing their structural durability. For this, an interaction of numerical and experimental procedures, supported by experience, is necessary.