The energy consumption of the process of joining steel sheets with the use of clinching with and without an additional rivet, and analysis of sheet deformation and mechanical strength of joints

Abstract

Abstract In the case of thin-walled structures, the geometric accuracy of the products is particularly important. The implementation of the parts joining process requires various tools and technological equipment. For clinching joints, their geometric quality, energy requirement of the forming process, and joint load capacity are very important issues. Clinching technology has been used for at least two decades, and research is still being conducted to improve it. This paper presents the results of research on the impact of process modification, i.e., the use of different tools and the shape of the additional rivet, on the joint geometrical quality, the energy consumption of the forming process, distortion of the DX51D + Z/275 steel samples, and the load capacity of the joints. The research was carried out using three different sets of tools. The effect of changing the shape of the rivet (the hole and its diameter and depth) on the reduction of the forming force and the energy consumption of the joining process was analysed. For joints made with different tools and with an additional rivet, an analysis of the size of the sheet deviation was performed. Changes in the geometric structure of the joint interlock and changes in the surface flatness of the sheets in the area of the joint axis were observed. The impact of the proposed rivet modification on the change in the effectiveness of the forming process was determined. Identification of the strength of the joints was also carried out in the shear test of the lap joint. The energy consumption up to fracture was calculated. It has been found that it is possible to significantly increase the joint load capacity and reduce the forming force of the clinch-rivet joints.