Brittle Fracture Strength of Fillet Welded Joints with Partial Penetrations

Abstract

The brittle fracture strength of fillet welded joints was investigated through fracture mechanics techniques.
Three point bend specimens of 50 mm thickness were extracted from the butt joint with partial penetration of mild steel. The critical crack opening displacement at fracture, δ_c, was evaluated and converted to the fracture toughness value in the linear fracture mechanics, K_c, by the use of the equation, K_c=√Eσ_Yδ_c, where E and σ_Y are Young's modulus and yield stress, respectively.
Brittle fracture tests on various types of fillet welded joints of 50 mm thickness were performed at low temperature. The stress intensity factors at the root of these fillet welded joints where combined modes of deformation appear were analyzed with the aid of the finite element method.
It was found that the fracture strength of the fillet welded joint can be evaluated on the basis of maximum tangential stress criterion.