Delamination failure in ceramic matrix composites: Numerical predictions and experiments

Analysis of coupled ply damage and delamination failure processes in ceramic matrix composites

“…The CMC material, the sub-elements, and the experiments discussed in the present paper are exactly the same as those reported in a previous work [19] and, hence, only a brief summary is provided here for completeness. Two CMC sub-element geometries, namely, tapered and insert, were considered in the experiments and analyses (Fig.…”

“…6 shows the FEA models of the sub-elements adopted in this work. These models are similar to those used in a previous work [19], and complete details may be found there. The sub-element geometry and test conditions allow for a 2-D modeling idealization.…”

“…Parametric studies revealed that including nominal friction between the sub-element and the fixture did not significantly affect the overall response. As discussed in Kumar and Welsh [19], a special loading arrangement was used in the experiment to allow for offset loading, and for consistency the same fixture with a rod was used to apply the load without any offset, i.e. for the axial pull load case discussed in this paper.…”

“…These test articles are referred to as sub-elements in the rest of the paper, primarily for two reasons: (1) it is a common terminology in the industry when referring to subsets of a component assembly, and also allows a distinction to be made between such specimens and standard test coupons used for material property determination; (2) to be consistent with the terminology used in a previous paper [19]. Both the ply damage mechanisms and the delamination process are modeled in a coupled fashion using finite element analysis (FEA).…”

“…Note that all of these methods require a pre-existing delamination crack. More recently, Kumar and Welsh [19] have used the cohesive zone finite element approach to predict both the initiation and the propagation of delamination in CMC sub-elements without requiring pre-existing cracks. This paper is an extension of the previous work reported in Kumar and Welsh [19] by including ply damage mechanisms in conjunction with delamination models.…”