FE MODELLING OF THE MOUNTING PROCESS OF METAL SCREW AND COMPOSITE PART

Abstract

The thread cutting process of threaded joint between metal screw and short glass fibre reinforced polymer part (PAGF30) was modelled by the Finite Element Method in order to establish the right joint geometry. An axial symmetrical model was developed for modelling the mounting process. The model takes into consideration the non-linear constitutive law of polymer, its large deformations and in-plane friction. In the contact process the metal screw was assumed to be rigid. As a result of simulation, the thread profile in the nut and surface pressures over the contact area were specified, which can serve as a basis for taking thermal load and tangential friction into consideration. In addition, the pre-tightening process and limit force of damage were determined. The resulting thread profile and limit force are in good correlation with the experimental data. The deviation can be explained with the material softening due to the higher temperature. The thermal process due to the frictional heat generation was separately analyzed. It was established that high temperature arises only in a small environment of the contact zone in the polymer part. The highest temperature was obtained on the second thread.