The focus of this study is aimed at characterizing the weave architecture in orthogonally woven polymer and ceramic—matrix composites. Three-dimensional (3D) geometric models of the unit-cells of four harness (4HS), five harness (5HS), and eight harness (8HS) satin weave morphologies are developed. The fiber bundle and matrix architecture in the 4HS, 5HS, and 8HS morphologies is represented via mathematical shape functions within the domain of the repeating unit-cells of the woven fabrics. This work brings together the non-uniform layer methodology of Kuhn and Charalambides [1] and the sub-cell modeling approach developed by Hewitt et al. [2]. In addition, this article introduces the novel concept of a `middle matrix layer' in capturing the ingress of matrix material away from undulating bundle regions, as documented by Morscher [3]. The geometry models developed herein account for a porous polymer matrix deposited over the woven mat via either resin film infusion (RFI) or resin transfer molding (RTM). This modeling also incorporates micro-structural intricacies observed in woven CMCs fabricated using chemical vapor infiltration (CVI) techniques for the deposition of the ceramic—matrix phase. Finally, results on the overall volumetric composite characteristics are reported.

No abstract

In this study, we employ detailed three-dimensional (3D) finite element models of plain and satin weave ceramic matrix composites (CMCs) as needed to establish the stress concentration around existing voids and their effect on the elastic response of these complex material systems. Fundamental 3D elasticity boundary value problems addressing the response of these materials under a combination of remote biaxial tension, in-plane shear, and thermal loading are utilized to characterize the matrix micro-stresses in the vicinity of large-scale macroscopic voids. The combined stress fields are then used to assess the conditions for the initiation of matrix cracking in such regions of high-stress concentration. Comparison of model results with available experimental data is discussed. Extensive parametric studies have yielded broad matrix cracking loci, which may be critical for the reliable use of woven CMCs in engineering applications.