High-Cycle Fatigue Behavior of a Self-tapping Timber Screw Under Axial Tensile Loading

The high-cycle fatigue behavior of a self-tapping timber screw is examined for axial tensile loading with R = 0.1. Based on 71 fatigue tests in the finite-life and long-life regime, Wöhler curves are derived for the failure modes thread area failure and head tear off . Comparisons with existing results of similar tests show equal behavior in the long-life regime and slight differences in the finite-life regime which cannot convincingly be attributed exclusively to either varying testing conditions or differences in the examined population. The fatigue verification according to EN 1993-1-9, detail category 50, is found to be highly conservative, whereas detail category 100 is shown to overestimate the observed fatigue behavior in the finite-life regime. Adding to existing observations on the fatigue behavior of a self-tapping screw, a first assessment of the decisiveness of geometrical and procedural differences in the screws can be made.