Industrial Equivalent Modelling of a Screw Assembly Subjected to a Thermal Load
Résumé
This paper presents a study of a screw assembly subjected to a thermal load. The main objective is to test the validity of current industrial practices regarding this kind of structure and loading. To do this, the study is divided into two parts. Firstly, experimental, detailed Finite Element Model (FEM) and analytical approaches are developed and confronted. Several thermo-elastic phenomena are studied. The study focuses on slips between the parts and under the screw heads, but also on loads in the parts and in the screw connections, and on the evolution of the preload in the screw connections. The detailed FEM and the analytical model take the microscopic behavior of the contacts into account by using a modified Coulomb model. The three approaches show rather good correlation. Secondly, industrial equivalent models of the assembly are developed and confronted with the previous work. These models are linear and the screw connections are represented in a very simplified way, by spring elements only. The stiffnesses of these springs in shear, bending and tension-compression are obtained by a purely analytical approach. The validity of the industrial equivalent models is then discussed, some conclusions are drawn and some prospects are suggested.