Stress concentration factors in two-dimensional composites: effects of material and geometrical parameters |
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Authors: | HD Wagner A Eitan |
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Affiliation: | Department of Materials and Interfaces, The Weizmann Institute of Science, Rehovot 76100, Israel |
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Abstract: | In the study of fracture processes in composite materials, the interactions between broken and intact fibers are of critical importance. Indeed, the redistribution of stress from a failed fiber to its unfailed adjacent neighbors, and the stress concentration induced in these, determine the extent to which a break in one fiber will cause more breaks in neighboring fibers. The overall failure pattern is a direct function of the stress concentration factors (SCFs). In this paper, we propose a new model for the SCFs in two-dimensional unidirectional composites containing broken fibers. A closed-form expression is derived for the SCF profiles as a function of material and geometrical parameters. The model differs significantly from earlier schemes, as the local effect of a fiber break on nearest neighbors is much milder than previously calculated, both as a function of the inter-fiber distance and of the number of adjacent broken fibers. Comparison with experimental results for silicon-carbide/epoxy composites demonstrates the validity of the proposed scheme. Since the overall fracture pattern in fiber composites is a direct function of the SCFs, the model may help shed light on fracture nucleation and growth in composites. |
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Keywords: | stress concentration interfacial shear stress critical length fracture fiber composites |
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