Estimation of the Stress Intensity Factor for 3D Cracked T – Joint

Abstract

This paper presents the numerical determination of stress intensity factor for a 3D cracked T -- joint using FRANC 3D software. The analysis preformed were linked between the finite element analysis using Abaqus software to obtain the stress state used in Franc 3D for stress intensity factor determination in crack presence in structure. For many applications like hydraulic Francis turbine rotors, the joints between blades and crow, and blades and rings are T-joints types with connections radius. In this paper an example of simplified T-joint with cracks presence is presented. For this cracked T joint structure a numerical analysis in bending and tension loadings was performed to obtain the stress intensity factors. The material used in analysis is a stainless steel named AISI 304. A stress state analysis was performed to obtain the maximum stress zone in T joint from where the crack can occurs. From this zone were initiate a quarter elliptical corner crack and propagated in the structure. For this crack propagated were obtained the stress intensity factors KI in loading mode I along the crack fronts. The stress intensity factor offer information for a future analysis, when in structure occur defects of cracks type related the operating condition.