ANALYSIS OF BIAXIAL LOADING EFFECT ON FRACTURE-TOUGHNESS OF REACTOR PRESSURE-VESSEL STEELS

The local stress-strain state (SSS) near the crack tip and its connect ion with the crack tip opening displacement and J-integral under biaxi al loading have been studied by finite element methods in elastic-plas tic finite strain statement. Numerical investigations have been perfor med for various crack lengths and two types of biaxial loading (tensio n and bending) under conditions of small- and large-scale yielding. To predict the biaxial loading effect on cleavage fracture toughness, th e procedure has been elaborated, this being based on the revealed regu larities for SSS near the crack tip under biaxial loading and brittle fracture criterion proposed earlier. Prediction of the biaxial loading effect on cleavage fracture toughness has been performed as applied t o reactor pressure vessel steel. The calculated results have been comp ared with available experimental data. Alternative approaches for pred iction of the biaxial loading effect on fracture toughness have been d iscussed. (C) 1998 Elsevier Science Ltd. All rights reserved.