Development of visualizing method for loading history and design method under non-proportional multiaxial loading

Abstract

This paper presents a design method to visualize the loading history under non-proportional multiaxial loading with the principal direction change. Definitions of principal stress and strain ranges and mean stress and strain were firstly introduced by utilizing Itoh-Sakane criterion for general multiaxial loading including non-proportional loading. Secondly, the method of calculating the non-proportional factor which expresses the severity of non-proportional loading was discussed for the general multiaxial 3D loading. The paper proposed a method of visually presenting the principal stress and strain trajectory under non-proportional loading histories that assists designers to understand the loading mode whether proportional or non-proportional under 3D multiaxial loading. An actual method of taking account of the stress and strain multiaxiality into practical design of components and structures was described. © 2013 The Japan Society of Mechanical Engineers.