Abstract
Three selected rigid plastics, namely polymethyl-methacrylate, polyvinyl chloride and glass-cloth reinforced polyester, were subjected to fatigue tests with four different fatigue testing machines. The results showed the following effect of the fatigue tester on the fatigue strengths of these materials.
(1) The effect of testing machine on the fatigue strength is appreciable. Therefore, a careful comparison of fatigue data resulting from the tests with different fatigue testers is necessary.
(2) The difference in the type of fatigue testing machines employed (constant stress-amplitude or constant strain-amplitude) as well as the difference in the method of holding specimens may affect the fatigue strength.
