PREDICTION OF MATRIX-INITIATED TRANSVERSE FAILURE IN POLYMER COMPOSITES

A study has been conducted of failure in unidirectionally-reinforced f iber composites loaded in tension normal to the fibers. The case consi dered is when this failure is governed by failure of the matrix rather than fiber/matrix debonding. Both yielding and cavitation-induced bri ttle failure of the matrix are considered. The latter mode of failure was suggested previously as the likely mode to occur in epoxies under stress stares that are purely or nearly hydrostatic tension. Three fib er packing arrangements (square, hexagonal and square-diagonal) with d ifferent fiber volume fractions were studied numerically by a finite e lement method to determine the local stress states. It is found that c avitation-induced brittle failure occurs much before yielding in all c ases. Experimental data taken from the literature support this finding . (C) 1996 Published by Elsevier Science Limited