Numerical model for two-bolted joints subjected to compressive loading

This paper deals with the dimensioning of two-bolted assemblies made up from joint prismatic subassemblies subjected to fatigue compressive loads coplanar with the screw axis. The presented study is complementary to a previous study relative to tension loading [A. Daidie, J. Chakhari, A. Zghal, Numerical model for bolted T-stubs with two bolt rows, Struct. Eng. Mech. 26 (3) (2007) 343–361]. However, one should note that the two loading cases are not similar since an additional influential corner contact problem occurs in the case of compressive loading. The main development in this paper relative to the previous study [A. Daidie, J. Chakhari, A. Zghal, Numerical model for bolted T-stubs with two bolt rows, Struct. Eng. Mech. 26 (3) (2007) 343–361] is taking into consideration this complex corner contact problem. In this framework, the local deformation between the subassemblies and the corner of the supporting structure is formulated and a non-linear expression of a constrained displacement is established. Moreover, the evolution of the contact zone under the compressive loading, which is not similar in the case of tension loading, is taken into consideration. Consequently, a new extended numerical model for compressive loading is established from unidirectional finite elements and validated by 3D finite element simulations. An algorithm which updates the contact stiffness matrix and sets out forces and displacements at each node of the subassembly is developed using C language program. Finally, a statistical software method is used as in the case of tensile loading. It is important to note that in the case of compressive loading, this statistical software method is not only used to establish the effect of the joint parameters, but also to identify and tune up parameters relative to the complex problem of the corner contact.