Effect of multi-impacts on a PMMA sheet material

When a specimen or component is subjected to repeated impacts it may eventually crack and fracture. A multi-impacts/impact fatigue study has been made for the first time on acrylic type PMMA (polymethylmethacrylate) sheet material with different type of notches and loading conditions. The study is conducted using a pendulum type repeated impact apparatus specially designed and instrumented for determining single and repeated impact strengths. Well-defined impact fatigue (S–N) behavior, having progressive endurance below the threshold single cycle impact fracture strength, with a limit, has been demonstrated.