Damage Tolerance Analysis of Bolt/Nut Assemblies

摘要

Probably one of the most challenging problems in fracture mechanics is related to211u001eits application to fastener and joints. By nature, not only the quality such as 211u001ematerial, manufacturing and mounting processes, of the fasteners are playing a 211u001erole, but also the stiffness, surface conditions and geometry of the parts are to 211u001ebe considered. Moreover, a fastener cannot be considered exclusively as an 211u001eindividual item, but has to be seen also as a link in a multi load path design. 211u001eFor a reliable integrity analysis of fasteners to be performed it is of paramount 211u001eimportance that accurate knowledge about load distribution and stress intensity 211u001efactors is available. In the current study the load transfer (tension and 211u001ebending) as well as stress intensity factor solutions for various crack locations 211u001eand sizes have been derived by advanced 3D FE analyses including threaded bolt 211u001eand nut. In addition, a large number of fatigue crack tests with Titanium and 211u001eSteel fasteners have been performed to: determine realistic defect shapes for