Simulation of the Flow Drilling Screw process for joining of Automotive components

In the automotive industry, lightweight design is a consolidated trend. In order to accomplish the emissions targets, the use of aluminium alloys is a common choice among car manufacturers. This decision leads to the need of performing multi-material joints, implementing also new types of joining techniques. The Flow Drilling Screw process, also known by the acronym FDS, is a joining technique that consists in the use of a threaded fastener. The fastener has the task of plastically deforming the workpieces by creating a thread through which a clamping force is finally applied. The material is softened before the deformation by exploiting the heat generated by the friction between the workpieces and the fastener tip, which rotates at high rotational speed. This process shows different advantages with respect to the traditional joining methods, such as welding, bonding or bolts-and-nuts joints, representing a valid technique at the level of chassis and body-in-white assembly. The present paper is aimed at building a finite element model using a general-purpose software through which it can be possible to simulate the FDS process in order to verify its feasibility before proceeding with physical tests or the production phase. After an introduction about the process, its characteristics and applications, the procedure for the model implementation is described. Then, a series of simulation results is presented and analysed to evaluate the influence of different process parameters and material combinations. The results are compared to those obtained through laboratory tests, in order to validate the proposed simulation model.