Accelerated characterization of creep response of an off-axis composite material

Abstract The accelerated characterization of the creep response of a unidirectional off-axis composite has been investigated. The composite used in this study was SMC-C50, a sheet molding compound containing 50% by weight of continuous glass fiber in a polyester resin. The fiber orientation studied was 15° with respect to the applied load axis. Short-time creep tests were performed at various stress levels at elevated temperatures. The creep data were modeled using the Findley eqution coupled with the fine-temperature-stress superposition principle. This modeling process is to determine the vertical and horizontal shift factors that are used to generate the master curve for long-time creep response. Two master curves were constructed for a reference condition of 23°C and 10·8 MPa. The proposed accelerated characterization procedure produced the smooth master curves of creep responses of 57 days and 400 days from several short-term (180 min) experimental creep data.