Modelling the load transfer in threaded connections by the finite element method

We introduce a finite element model for stress analysis of threaded connections. Instead of modelling individual threads, the thread zone is replaced by a layer of elements with orthotropic properties. The principal directions of orthotropy depend upon the thread geometry and upon the direction of load, which is not necessarily known a priori. Both conventional and tapered threads are considered. The latter problem is nonlinear, as the number of threads in contact is a function of the load. Numerical results for conventional and tapered threads agree well with theoretical and exeprimental results in the literature.