Evaluation of Polymer Strength and Durability Under Fatigue Loading

This technical report evaluates the loss of strength and durability in polymers due to fatigue loading and manufacturing artifacts, specifically focusing on NORYL™ 731 samples. The study investigates the impact of production artifacts, such as knit lines, on the mechanical properties of the material. Tensile testing was conducted to measure modulus, ultimate tensile strength (UTS), and elongation at break for both single and dual gate samples. The results indicated that while the modulus remained largely unaffected, the dual gate samples exhibited a significant reduction in elongation at break. Fatigue testing revealed a stark contrast in fatigue life, with single gated samples achieving 30,000 cycles at 50% UTS, compared to only 6,000 cycles for dual gated samples. The report highlights the critical importance of incorporating fatigue testing in the material selection process to prevent costly failures during the product lifecycle. Additionally, it discusses the various factors affecting polymer durability, including molecular structure and production conditions.