Micromechanical FE Analysis of SiCf/SiC Composite with BN Interface

Abstract

The current study presents a micromechanical Finite Element Analysis (FEA) methodology to predict the room temperature transverse tensile failure behavior of a SiCf/SiC composite (Silicon Carbide Fiber/Silicon Carbide Matrix) with Boron Nitride (BN) fiber coating. In order to accurately capture the constituent level damage initiation and propagation, three-dimensional Representative Volume Element (RVE) models are generated by discreetly modeling the fiber, the matrix, and the coating material. In addition, various geometrical parameters such as the random distribution of the fibers, the fiber-coating, and the matrix-coating interface decohesions were taken into account. For modeling the fiber-coating and the matrix-coating interface interactions, cohesive surface approach within the cohesive zone module of Abaqus® was used. In order to capture the coating and the matrix material fracture behavior, the eXtended Finite Element Method (XFEM) approach was employed. Using the proposed numerical methodology, detailed local stress-strain and damage analysis lead to an observation that the chosen interface interactions have a predominant effect on the RVE damage behavior. Moreover, local fiber placement and the RVE size have a significant influence on the damage initiation threshold and hence the predicted strength and failure strain of the RVE. © 2019, Springer Nature B.V.