Stress-based optimization of assembly surface mechanical properties oriented to stress-uniform assembly

Abstract

Stress-uniform assembly is favorable for ensuring the precision and performance stability of precision electromechanical systems. Process compensation, assembly process optimization and assembly surface topography optimization are three typical ways to regulate the assembly stress distribution. Assembly surface mechanical properties optimization is a new and promising technique for achieving uniform stress distribution in assembled parts. This study takes that direction and investigates how variation in assembly surface material stiffness (i.e., Young's modulus) give rise to the variation in von Mises stress in assembled parts. To homogenize the von Mises stress distribution in assembled parts, the stress-uniform assembly-oriented material stiffness optimization model is constructed on the basis of finite element discretization. A stress-based material stiffness optimization method, which does not require sensitivity analysis, is developed by directly linking the amount of change in material stiffness to the value of von Mises stress. The feasibility and effectiveness of the stress-based assembly surface material stiffness optimization are demonstrated by a design case containing three elastic contact bodies, where both single-load and multi-loads conditions are considered. Some new phenomena during the assembly surface material stiffness optimization are also observed and explained.