BOUNDARY-ELEMENT METHODS FOR THE ANALYSIS OF CRACK-GROWTH IN THE PRESENCE OF RESIDUAL-STRESS FIELDS

Two boundary element methods of simulating crack growth in the presenc e of residual stress fields are presented, and the results are compare d to experimental measurements. The first method utilizes linear elast ic fracture mechanics (LEFM) and superimposes the solutions due to the applied load and the residual stress field. In this method, the resid ual stress fields are obtained from an elastoplastic BEM analysis, and numerical weight functions are used to obtain the stress intensity fa ctors due to the fatigue loading. The second method presented is an el astoplastic fracture mechanics (EPFM) approach for crack growth simula tion, A nonlinear J-integral is used in the fatigue life calculations. The methods are shown to agree well with experimental measurements of crack growth in prestressed open hole specimens. Results are also pre sented for the case where the prestress is applied to specimens that h ave been precracked.