Sub-Scale Testing for Strength and Creep-Rupture of Polymers

In the present research, a sub-scale specimen geometry was proposed for the determination of the tensile strength of polymers. Tensile strength of an aerospace epoxy (8552) was measured at various temperatures using the proposed testing approach and the measured data were compared to data measured using standard-size specimens. According to the experimental data, greater strengths were obtained using sub-scale specimens. This phenomenon was related to the lower probability of having larger flaws in smaller-size specimens. In addition, a creep-rupture master curve for the polymer was obtained by shifting strengths measured at various temperatures, according to an accelerated testing methodology (ATM) based on the time–temperature superposition principle. Ultimately, the proposed sub-scale testing approach may prove feasible for determining tensile strength and the long-term creep strength of a polymer using standard laboratory dynamic mechanical analysis (DMA) equipment.