1. Fatigue sizing

In the case of fatigue sizing of aeronautical assemblies working in mat-shear, made with bolts mounted with very little clearance or with interference, conventional calculation does not take bolt pretension into account, even though installation manuals recommend high tightening torques .

When the bolts are fitted with a small clearance and the contact surfaces are such that the coefficients of friction at the interfaces are high (0.2 to 0.5), we don't think it's a good idea to neglect the tightening preload. Indeed, it significantly modifies the state of stress in the critical zone of the parts, located around...