SUBCRITICAL CRACK GROWTH IN CVI SiC_f/SiC COMPOSITES AT ELEVATED TEMPERATURES: DYNAMIC CRACK GROWTH MODEL

摘要

A dynamic crack-growth model has been developed to predict slow crack growth in ceramic composites containing nonlinear, creeping fibers in an elastic matrix. Mechanics for frictional bridging and nonlinear fiber-creep equations are used to compute crack extension dynamically. Discrete, two-dimensional fiber bridges are employed, which allows separate bridge "clocks", to compute slow crack-growth rates for composites containing Nicalon-CG and Hi-Nicalon fibers.