THERMAL-STRESS CONCENTRATION DUE TO IMPERFECT ADHESION IN FIBER-REINFORCED COMPOSITES

Thermal stress and strain analyses have been performed in unidirection al fiber-reinforced composites by considering the concept of an interp hase between the fiber and matrix phases. The thermal and elastic mate rial properties of the interphase are assumed to be variable and to de pend on the degree of adhesion developed between fiber and matrix. An analytical approach is developed for the solution of the appropriate g eneralized plane strain steady-state thermoelastic problem. This appro ach is an extension of the homogeneous subdomain method, requiring app ropriate discretization of the problem domain into an appropriate numb er of subdomains. Application of continuity and compatibility conditio ns for the temperature field and the thermoelastic stress potential re sult in a system of linear equations, the numerical solution of which supplies all necessary constants for evaluation of the solution of the problem. Numerical results are given for a wide range of the paramete rs involved, including material properties and imperfect adhesion coef ficients. The introduction of the so-called degree-of-adhesion coeffic ients gives new insight into the failure mechanisms developed along th e fiber/matrix interface. Application to the proposed model of imperfe ctions in the adhesion between fiber and matrix shows very interesting results and explains the failure mechanisms for such materials. (C) 1 997 Elsevier Science Limited.