Expression of Inherent strain in Form of Function and its Estimation

Estimating and Measuring Methods of Residual Stresses Using Inherent Strain Distribution Described as Functions (Report 1)

Abstract

When three dimensional welding residual stresses are measured based on inherent strains using Finite Element Method, too many inherent strain components in elements have to be specified to express their distribution. If these are determined experimentally, measurements of elastic strains must be made for points more than the inherent strain components. In order to reduce the number of measurements and to find the general distribution pattern of inherent strains, the functions are introduced to express the distribution of inherent strains instead of specifying those in individual elements. With the aid of functions describing the distribution of the inherent strains, the total number of unknown constants can be greatly reduced.
To verify this new method, residual stresses and inherent strains in bead-on-plate welds are estimated. The estimated residual stresses by simple functions show very good accuracy compared with those computed by thermal elastoplastic Finite Element analysis.