Further development of a numerical method for analyzing the load capacity of clinched joints in versatile process chains

Christian Roman Bielak,Gerson Meschut,Mathias Bobbert,Max Böhnke

doi:10.25518/esaform21.4298

Abstract

In many branches of production, components using large number of joints are combined together to make complex structures. The use of mechanical joining techniques offers the possibility to join structures with a wide range of material/geometry configurations. Due to changing in material properties during the production of formed parts, the robustness of the joint must be guaranteed. In this regard, a numerical method has been developed to predict the geometrical properties of the joint as a function of pre-straining of the metal sheets. In this way, the material combination and the joining tools are to be considered. The resulting metamodels were used to estimate the robustness of the joining process. In this study, the method is extended by a numerical load capacity model, which is generated from the joining process model using an automatic algorithm. The simulation model used for predicting the load capacity is validated by experiments. It is shown that the resulting automatic method is able to completely map a process chain and to predict the load capacity of the mechanical joints under consideration of the pre-strain. Furthermore, the correlation between the pre-strain and the load capacity is presented.

Highlights

Mechanical joining technologies are becoming increasingly important for multi-material lightweight constructions, e.g. for car bodies in white
A study [6] investigated the development of a five-stage simulation process chain capable of numerically predicting the SPR joint geometry and strength under various loading conditions such as shear, transverse tensile and peel stress
A numerical method presented in [8] is further developed to analyze the influence of forming processes prior to clinching processes

Summary

Introduction

Mechanical joining technologies are becoming increasingly important for multi-material lightweight constructions, e.g. for car bodies in white. For various metal constructions, such as body-in-white, components are usually deep-drawn in order to be pre-formed for the following processes This pre-forming influences the joinability in relation to the formability of the materials and must be taken into account when designing joints. The pre-forming of the punch-side material has more influence on the joining parameters than the die-side material. The relationship between pre-deformation of the component and the characteristic joint properties, as simulated in study [8], is here extended by a subsequent shear load capacity simulation This further development makes it possible to investigate the relationship between the presented characteristic parameters and the effective maximum shear force

Methodical approach

FEM simulation

Results

Summary