Fatigue life assessment of bolted connections

The work presented in this paper deals with the fatigue damage assessment of bolted joints. The influence of the preload is particularly underlined as it is shown that it strongly improves the fatigue resistance of the bolt whatever the geometrical parameters are. A 3D tee-stub model with the bolt submitted to preload force is simulated by using the Salome-Meca FEM software. A parametric study is also carried out to analyse the influence of the bolt location m and the column flange thickness tf onto the bolt loading. In order to analyse the effect of the stress concentration generated by the head-shank transition of the screw, a second 3D finite bolt element model is developed. This allows to exhibit multiaxial stress states in the vicinity of the fillet radius. Finally, a multiaxial fatigue post-treatment tool has been implemented on Matlab software for damage assessment purpose. Two multiaxial fatigue criteria approaches contribute to this tool and may be used for fatigue behaviour prediction. The so-called critical plane approach (Dang Van criterion) and the integral approach (Zenner criterion) may consequently be compared for that analysis