Shear-Lag Analysis of a Hybrid, Unidirectional Composite With Fiber Damage.
CLEMSON UNIV SC DEPT OF MECHANICAL ENGINEERING
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This study considers the development of a method of analysis capable of predicting accurately the fracture behavior of unidirectional hybrid buffer strip composite laminates. Three particular solutions are discussed in detail first, the case of broken fibers in a unidirectional half-plane second, the case of adjoined half-planes of different fiber and matrix properties and finally, the solution of two half-planes bounding a third distinct region of finite width. This finite width region represents a buffer strip and primary attention is given to the potential of this strip to arrest a crack that originates in one of the half-planes. The analysis is based on a materials modeling approach using the classical shear-lag assumption to describe the stress transfer between fibers. Explicit fiber and matrix properties of the three regions are retained, and changes in the laminate behavior as a function of the relative material properties, buffer strip width, and initial crack length are discussed. Ultimate failure of the laminate after crack arrest can occur under increasing load, either by continued crack extension through the buffer strip or by fiber breakage in the undamaged half- plane. That is, for certain choices of relative material properties and width, the crack can jump the buffer strip. As a special case of the buffer strip problem, a solution is obtained for a unidirectional finite width strip containing an arbitrary number of broken fibers. The stress concentration factors for the finite width strip are compared with those for an infinite region and finite width correction factors are given. MM
- Laminates and Composite Materials