Abstract:

Non linear contact analyses of lugs and pins under different fitting conditions have been done by FEM to simulate the typical working conditions of different kinds of lugs in aircraft structures under loads in various directions.In the FEA models, several kinds of finite elements have been used. First, critical sites are obtained by FEA of the lugs without cracks under various loads. Second, the SIF are computed by the FEA of lugs with cracks initiated at the critical sites under the same loads. Then several sets of curves of SIF have been given for lugs of different shapes under different loads. Based on those SIF, some fracture mechanics characters of the lugs have been found. The accuracy of the results and the reliability of the numerical method and the computer codes used in this paper have been demonstrated by comparisons between SIF of some lug obtained here and those in literature. Therefore, the numerical results and some conclusions given in this paper can be used as a basis for the damage tolerance design of lug connecting.

Key words: stress intensity factors(SIF), critical sites, finite element analysis (FEA), lugs