Classification of stress in the ligament of a longitudinal crack in an ovalizing elbow

This paper deals with an experimental study aiming at developing an assessment procedure to analyze the stability of a part through thickness longitudinal crack in an elbow subjected to bending. The material is a very ductile 316 L steel tested at room temperature. Fourteen tests were performed with blunted notches. A refined instrumentation was installed close to the cracked section in order to give strain distribution in the remaining ligament. Evaluation of experimental results was conducted together with a complete 3D finite elements elastoplastic analysis. The aim is defining the limit state in the cracked section. Some proposals are presented and discussed. A simple kinematical model of the cracked ligament gives interesting comparisons with experimental and numerical results