Stressed oxidation life predication of 3D C/SiC composites in a combustion wind tunnel

To improve safety and reliability, a method which can predict the life of C/SiC structures in severe environments accurately is need for designers. A multi-zone load bearing model for stressed oxidation of 3D C/SiC was suggested. Based on the model, the life prediction functions for wind tunnel environments were derived from the nature of oxidation of carbon fibers. Most of material and environmental parameters are taken into consideration. The former include properties of carbon fiber (i.e., density, modulus and thermal expansion coefficient (CTE)), CTE of SiC matrix, braid angle of fiber perform, and thickness of sample. The latter involve gas flow velocity, gas composites, molar fraction of oxidant, load and temperature. The effects of temperature, load, atmosphere pressure and partial pressure of oxygen were also introduced to the equation by the width of crack. It is proved by the experimental results that the predication results are accurate under the loading ranging from 100 to 160 MPa in a wind tunnel.