Effect of strain rate on the mechanical behaviors of SiC fiber

In the present paper, tensile experiments of SiC fiber bundles under different strain rates (quasi-static: 10^–4–10^–3 s^–1, dynamic: 200–1200 s^–1) are carried out and the corresponding stress-strain curves are obtained. It is found that the mechanical properties of SiC fiber bundles are rate-dependent: the elastic modulus E, strength _b and the failure strain _b remain unchanged under quasi-static condition, while they apparently increase with increasing strain rate under dynamic condition. Based on the fiber bundles model and the statistical theory of fiber strength, a bi-modal Weibull statistical model of the strain rate dependence is adopted to describe the strength distribution of SiC fiber, and the Weibull parameters are obtained by the fiber bundles testing method. Consistency between the simulated and experimental results indicates that the model and the method are valid and reliable.