Influence of frequency and stress concentration on fatigue behavior of short glass-fibre reinforced polyamides

Materials such as short fibre reinforced polyamides are being increasingly used in structural durability applications. Hence, application related material data are required for the dimensioning of components made of these materials. However, the procedures for the performance of fatigue testing are still under discussion. In view of this current status, this paper gives attention to experimental investigations regarding the influence of test frequency on the fatigue life of short glass-fibre reinforced polyamides. Fatigue tests with constant amplitudes were carried out and simultaneously the data of hystereses and surface temperature were recorded and subsequently analysed. In addition to the value of load level, the influencing parameters stress concentration (notch factor), which reduces the highly stressed material volume, and the mean stress (stress ratio) were considered in the assessment of the influence of frequency on the fatigue life.