A mixed XFEM and CZM approach for predicting progressive failure in advanced SiC/SiC CMC component

Abstract

This research work focused on simulating different fracture modes in the high-stress concentrated region of an advanced SiC/SiC CMC component at the macroscopic scale in consideration of increasing cost and time during experimental tests of CMCs. A hybrid of extended-finite-element-method (XFEM) and cohesive-zone-modeling (CZM) was utilized to predict mode-I and mode-II fracture behavior, respectively. The cohesive element (CE) layers were used as fiber-tow interfaces in the stress-concentrated region where mode-II failure was supposed to occur. The 1st crack initiation and its further propagation were found to be dependent on XFEM damage criteria, whereas delamination was observed at the damage-front CE layers. The simulated force-displacement relationships were compared with the experimental ones, where stiffness and serrations in the force-displacement curve corresponding to the delamination matched quite well. With concern to predicting the fracture behavior in a complex-shape component of SiC/SiC CMCs, XFEM with CZM methodology can be a reliable method in the near future.

Keywords

• SiC/SiC CMC
• FEM
• XFEM
• CZM
• 1st cracking
• Delamination