Warm pre-stressing tests on specimens with semi-elliptical cracks and analysis of the results

This paper describes a study, made in France, of the effect of warm pre-stressing (WPS) in the presence of semi-elliptical defects. bjective was to confirm the validity of our approach which combines testing and modelling for analysing a more complex geometrical configuration than one with a simple crack under WPS conditions. nvolved ad hoc tests on compact tension (CT) specimens of 18MND5 steel (equivalent to ASTM A533B plate) with semi-elliptical cracks:• sts were conducted under isothermal and warm pre-stress conditions in order to quantify discrepancies associated with the shape of the defect and the type of thermal transient. ent types of thermal transients were studied to assess any impact on the positive effect of warm pre-stressing. nvolved also 3D modelling of tests in order to be able to apply either global approach with the use of the master curve and the Wallin method or local approach criteria with the modified Beremin model. confirmed the warm pre-stressing had an effect, even in the case of tests conducted at low levels of pre-stressing. The supporting numerical interpretations made demonstrated the ability of the simplified global approach (Wallin method) and the local approach (modified Beremin model) to predict the positive effects of warm pre-stressing.