轮盘剖面形状的优化设计

本文提出一种实用的轮盘优化模型,它可用中心孔半径、轮毂轴向厚度和外半径、轮颈半径以及轮毂、轮缘与轮辐转接处的转接角等几何参数来描述,整个轮盘可近似为由一系列不等轴向厚度的圆环组成。一个能自动生成计算截面的子程序,响应上述诸参数的变化,灵活地生成任意个径向厚度各异的不等轴向厚度的小圆环,以这些小圆环的轴向厚度和上述诸几何参数为设计变量,以轮盘设计的五个应力准则为约束条件,以轮盘重量为目标函数,采用随机射线法+随机投点法的组合优化方法,加速收敛,达到轮盘重量最轻,剖面形状最优。

HIGH- AND LOW-CYCLE COMBINED FATIGUE AND ITS TEST TECHNIQUE

A simple combined fatigue test facility is introduced, which produces and controls high- and low-frequency combined load spectra by means of a closed circuit consisting of a microcomputer and a hydraulic servo unit. The minor-cycle frequency attains 100Hz with a force amplitude of about 500kg,but higher frequency(say, 400-500Hz) may be attained if a better servo unit be available.About 50 specimens of aluminum alloy LY12-CZ have been tested and the results show that both the minor-cycle frequency and force amplitude have a detri-mental effect on crack initiation life.A ratchetting phenomenon appeared as the minor-cycle frequency was lowered to l0Hz. It is probably a "deformation failure" in this case.