Dynamic stress analysis of plates of different kinds material.

Abstract

Structures of machine parts subjected impact load often suffer unexpected damage, which is remarkably different from the observed in static cases. Generally, the reflection and interferference of stress-wave play an important role in dynamic cases, and it is desirable to study the time variation of the stress distribution, and especially the value of dynamic stress concentration factors around the boundaries of different kinds of materials. Hence, we analyzed stress propagation and dynamic stress concentration phenomena around the boundary of different kinds of materials in a plate by utilizing the strain gage method, the dynamic photoelastic method and also the finite element method. We found that two-dimensional dynamic stress concentration factors obtained by the present three methods are in general agreement and if the ratio of E2 (young's modulus for the different materials)/E1 (young's modulus for the matrix) is small, the dynamic stress concentration factor is small, but the position of maximum stress occurs at the circular bounday of the matrix. On the other hand, if the ratio of E2/E1 is large, the dynamic stress concentration factor is large, and the position of maximum stress occurs at the boundary of the circular hole in various types of materials.