MATRIX STRESS VARIATION DUE TO FIBER DEBONDING IN FIBROUS COMPOSITE MATERIALS
Abstract
In this study the stress field around a single fiber in a fibrous composite is investigated as the fiber debonds from the matrix. Both the problem of the discontinuous fiber with tip debonding and the problem of the broken fiber with debonding at the breakage site are discussed. To obtain the solution to the problem, three avenues of approach are employed. The first is a photoelastic experimental analysis performed on the two-dimensional analog of the problem in order to obtain insights into the expected stress field. Secondly, a three-dimensional axi-symmetric finite-element analysis is performed on a concentric cylinder element. Finally, the solution is obtained to an approximate boundary value problem for the concentric cylinder material element. A displacement function is assumed on the debonded portion of the fiber-matrix interface to overcome the difficulties associated with mixed boundary conditions on a single coordinate surface. The function is chosen consistent with the finite-element results. Results and insights gained from the three approaches are compared and interrelated to yield information on the stress field due to fiber debonding.
Degree
Ph.D.
Subject Area
Mechanics
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