Simulation of Crack Propagation in a Pre-Cracked Tube Subject to Thermal Cyclic Loading

Felix, S.

This study was undertaken to reproduce numerically crack propagation tests in a pre-cracked tube subject to thermal cyclic loading (radial temperature gradients varying with time). The experimental tests simulated are part of the ATTF experimental program (Air cooled Thermal Transient Test Facility), carried out at OEC/PNC. The simulation is performed using two techniques, the Energy Release Rate Method (or G-Theta Method), Programmed in the Finite Element computer code CASTEM 2000 developped at CEA (FRANCE), and the Js Simpilified Method of the A-16 Appendix of the French RCCMR. It is then compared to experimental data and to numerical results obtained from PNC's Finite Element computer code FINAS. From elastic and plastic Finite Element analysis, the G-Theta procedure and the Js Method allow us to obtain the evolution of the J-variation versus the crack length. Paris' law then leads to an evaluation of the crack length versus the number of cycles. It is shown that the elastic prediction of crack growth using the G-Theta Method is close to FINAS' results, and very close to measured values. The plastic prediction using the Simplified Method is slightly better than the one using the G-Theta Procedure, but both agree well with the experimental results. FINAS' predictions in the plastic case are better, but a different definition of the J-variation is used. This study confirms that the G-Theta procedure of CASTEM 2000 and the Js-Method of the A-16 Appendix of the French RCCMR are in good agreement with PNC's simulation methods, and that they are well suited for crack propagation analysis in the case of thermal cyclic loading.