Abstract:

The traditional stress severity factor (SSF) approach is almost unable to obtain the SSF value under complex geometry and loading boundaries. The maximum stress at the edge of a hole can be obtained easily by 3D FEM, but the process is time-consuming if the quality and filling status of the pin-loaded holes are included in the FE model; moreover, the maximum stress obtained by FEM cannot be readily used to predict the fatigue life of a plate. Therefore an equivalent SSF approach is proposed in this article to predict the fatigue life of a plate with loading-born holes under complex geometry and loading boundaries. The equivalent SSF value is deduced by the superposition of two uniaxial stress fields in the region of the hole, and the effects of complex geometry and loading boundaries are considered at the same time. The fatigue life of a multi-fastener plate of an aircraft tank is analyzed and verification test is made as an example. The results show that the fatigue life estimation is in good agreement with the experimental results.

Key words: multi-fastener joint, stress field, stress severity factor, stress concentration, fatigue