Structural integrity assessment of plates containing embedded cracks-part I: Finite element fracture analyses

Abstract In this two-part paper, guidance for assessing plates containing embedded elliptical cracks under complex loading conditions is developed, based on the fracture mechanics validation of the limit load solutions using the finite element (FE) J solutions. In Part I of this paper, elastic-plastic 3D FE analyses are performed for plates with embedded off-set elliptical cracks under combined biaxial stresses and through-thickness bending for developing a FE J database containing 612 cases. Totally 18 cracked plate models are created. For each cracked plate, 17 load combinations are considered and two material strain hardening exponents are analysed. The obtained plastic J solutions are correlated as the EPRI type fully-plastic J factor h1. The effect of the applied normal stress parallel to the crack plane, σ2, on the elastic-plastic J behaviour is investigated and it is found that the EPRI linear addition J estimation scheme may not describe the elastic-plastic J behaviour very well for cases under combined bending moment and σ2. The limit load validation using the FE J solutions is detailed in Part II of this paper.