Development of a Computer Code for Modeling the Progressive Damage and Failure of Fiber-Reinforced Ceramic Composites

Development of a computer code for simulating the progressive damage and failure of fiber-reinforced composites is described in this Phase I Small Business Innovation Research Proposal. The computer code will combine a fracture mechanics treatment of the stable growth of partially-bridged surface and internal (penny-shaped) cracks with a compliance analysis to predict progressive damage (decreasing elastic modulus) with increasing monotonic or cyclic loads. The input to the code will include constituent material properties (elastic modulus, Poisson's ratio and fracture toughness), interface properties (friction stress), bulk properties (fiber volume fraction, laminate geometry, residual stresses), an initial distribution of microcracks governed by the microstructure (fiber distribution) or contact-induced damage, and nature of loading. The code output may take the form of a simulated stress-strain curve for monotonically increasing loading, or progressive change in compliance under static or cyclic loading. The Phase I effort will be restricted to unidirectional composites and modeling of the inert (rate independent) behavior of ceramic composites. Extension of the code to multi-ply laminates to predict progressive damage under sustained time-dependent crack growth and/or cycle-dependent crack growth (fatigue) will be deferred to Phase II.