Salmi, H, EL Had, Kh, EL Bhilat, H, Hachim, A. Numerical Analysis of the Effect of External Circumferential Cracks in Transition Thickness Zone of Pressurized Pipes Using XFEM – Elastic-Plastic Behavior. Journal of Solid Mechanics. 2020;12(3):620-631. 10.22034/jsm.2019.1882104.1511