Three-dimensional asymptotic stress field at the front of an unsymmetric bimaterial wedge associated with matrix cracking or fiber break

• Published in: Composite structures Vol. 78; no. 2; pp. 254 - 263
• Main Authors: Chaudhuri, Reaz A., Jack Chiu, Sou-Hsiung
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.04.2007; Elsevier Science
• Subjects: Applied sciences; Bimaterial wedge; Composite; Composites; Exact sciences and technology; Fiber; Fiber break; Forms of application and semi-finished materials; Fundamental areas of phenomenology (including applications); Interfacial crack; Matrix; Matrix crack; Physics; Polymer industry, paints, wood; Solid mechanics; Static elasticity (thermoelasticity...); Stress singularity; Structural and continuum mechanics; Technology of polymers; Three dimensional; Stress singularity; Matrix; Interfacial crack; Composite; Bimaterial wedge; Fiber break; Fiber; Matrix crack; Three dimensional; Elastic constant; Fibre fracture; Singularity; Free field; Solid solid interface; Half space; Modeling; Series expansion; Eigenvalue problem; Stress concentration; Stress analysis; Free boundary; Breaking in; Deformation modulus; Far field; Wedge; Matrix fiber interface; Matrix fracture; Interface crack; Fiber orientation; Asymptotic approximation; Angle of incidence
• ISSN: 0263-8223; 1879-1085
• DOI: 10.1016/j.compstruct.2005.09.013

A combined approach for prediction of the singular stress fields at the interfacial fronts of fiber breaks and matrix cracks is presented. A recently developed eigenfunction expansion method is employed for obtaining three-dimensional asymptotic displacement and stress fields in the vicinity of a point located at the front of a bimaterial wedge of general (unsymmetric) geometrical configuration (with respect to bimaterial interface), and subjected to extension/bending (mode I) and in-plane shear/twisting (mode II) far field loading and free–free wedge-side boundary condition. Each material is isotropic and elastic, but with different material properties. The material 2 (fiber in the case of matrix cracking or matrix in the case of fiber break) is always taken to be a half-space, while the wedge aperture angle of the material 1 is varied to represent varying matrix cracking or fiber break incidence angles at the interfaces. Numerical results pertaining to the variation of the lowest eigenvalues (or stress singularities) for various wedge aperture angles of the material 1, subjected to the afore-mentioned wedge-side boundary condition, are also presented. Variation of the same with the shear moduli ratio of the component material phases is also an important part of the present investigation. The conclusion drawn from the present asymptotic analysis of the matrix cracking problem is in agreement with that of an earlier investigation based on the energy based criterion. Similar conclusion drawn from the present asymptotic analysis of fiber break problem is in agreement with that of an energy based criterion derived here in analogy to the corresponding matrix crack problem by another investigator.