CONSIDERATION ON IDENTIFICATION METHOD OF RESIDUAL-STRESSES BY BOUNDARY ELEMENT METHOD

Residual stresses in structural members occur due to machining, welding, and so on. For estimating the residual stresses, it is necessary to clarify numerous unknown qualities, the shape and dimension of the body force acting region. The boundary element method (BEM) has the advantage of transforming a region type problem into a boundary type one. So, as a method for estimating in a nondestructive manner some unknown internal residual stresses from the data of known boundary displacements and tractions, BEM is in principle of analysis, considered to be one of the most suitable methods. In the present paper, inverse analysis based on BEM was formulated and the method for identifying residual stresses in a plate and a cylindrical tube was developed. As an example of the method, an identification simulation of residual stresses which occurs owing to local heating and cooling was performed. As a result, it turned out that the evaluation parameter R1 and R2, the sum of body forces with opposite direction, are useful indices for the location search of the acting body force in inverse analysis. It is possible to identify the residual stressess in a plate with sufficient accuracy by thus using the obtained body force. Next, we extended the method to the identification problem of residual stresses in an axisymmetric body and demonstrated that it is possible to identify the magnitude of the residual stresses occurring at the welding region in a cylindrical tube. © 1990.