INFLUENCE OF THE TEST GEOMETRY ON THE FATIGUE BEHAVIOR OF FIBER REINFORCED PLASTICS IN TENSION AND INTERLAMINAR SHEAR AT RT AND 77 K

摘要

In view of applications of fiber reinforced plastics as insulating materials for the windings of the superconducting magnets in the ITER device and because of its pulsed operation, the fatigue behavior of these materials has to be assessed under conditions including the appropriate radiation environment at the magnet location. Since the established standards, e. g. for tension-tension fatigue measurements involve sample sizes, which are far too large for experiments under a radiation environment, scaling experiments were made in order to investigate the influence of the sample geometry on the fatigue behavior for tension-tension fatigue specimens. Various sample sizes, including the standard geometry, were chosen for the experiments at room temperature and at 77 K. Furthermore, different double lap shear geometries were tested under tension-tension fatigue loading, in order to assess the influence of the shear length and the sample thickness on the fatigue behavior in the interlaminar shear mode.