Analysis of dynamic fracture propagation in steel pipes using a shell-based constant-CTOA fracture model

Abstract

In this paper, a finite element (FE) model with shell elements using a constant crack tip opening angle (CTOA) as fracture criterion was implemented for the simulation of dynamic fracture propagation in steel pipes. The new model was developed to improve computational efficiency over current CTOA models while retaining a high level of numerical accuracy. The commercial FE code ABAQUS was used to generate the meshes and perform the analyses. The proposed model was first used to reproduce data from an existing CTOA model of an American Petroleum Institute (API) X65 steel, matching the steady-state fracture velocity within a maximum difference of 5% while drastically reducing the computational time required. The model was then used to analyze recent experimental data from a full-scale pipe burst test of a Japanese Industrial Standard (JIS) steel STPG370, matching the crack velocity data within 4%. It was thereby demonstrated that FE analysis using this shell-based constant-CTOA model is an efficient method for describing dynamic fracture propagation in steel pipes and can be used as an engineering tool to develop fracture driving force based on CTOA.