Slewing bearings are bearings of very large diameter used for cranes, radar dishes, tunnel boring machines, etc. The two bearing rings are clamped to the structure by preloaded high-strength screws or bolts. The connection is like a thick and narrow cylindrical flange, which includes a large number of fasteners. It is subjected to extreme loading which is variable in time. Given the low fatigue resistance of threaded elements, they must be sized with a great accuracy. This article presents a simple and efficient numerical model specially developed for the sizing of these connections. The originality of the modelling process lies in the use of a hybrid finite element. This element has the general behaviour of a ring (cylindrical shell element), except for the axial direction where its stiffness is the local stiffness that governs the behaviour of the bolted assembly. By discretising the ring in several elements, this formulation can take into account non-linear stiffness distribution in the assembly and in particular the effect of the load application height. This model was then validated via several 3D finite elements simulations and gives excellent results.
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