Clinching thin sheet metal - Behavioral modeling

Clinching is a mechanical assembly technique for metal sheets. The basic principle is to connect two metal sheets by stamping between a punch and a die. The sheet undergoes local cold plastic deformation, forming a connection point. Cold forming is used as a joining technique.

As part of a wide-ranging European project on assembly systems for the automated production of standard steel components for the construction industry, clinching was studied at the University of Liège: numerical models simulating the clinching process were developed, and an in-depth study of the behavior of a clinched point subjected to shear stress was carried out. To this end, shear tests on simple assemblies, with only one or two clinched points, were carried out and numerically reproduced using Lagamine finite element software. Based on the findings of these studies, an analytical strength model of a clinched point subjected to shear was developed.

Tests, numerical models and analytical developments have also been carried out for complete clinched assemblies subjected to shear and/or bending. One of the aims of the research is to develop formulas for rapidly estimating the strength and stiffness of clinched assemblies.

Any construction assembly is made up of one or more components (bolts in tension, compressed beam flange, etc.). To assess assembly behavior, the component method recommends isolating each component and studying its behavior separately. For simple connections, the strength of the connection corresponds to that of the weakest component. This so-called "component method" has been adopted in the Eurocodes for steel and composite construction. It can also be applied to clinched joints. In such joints, a single component is identified: the clinched point subjected to shear (hereinafter referred to as the "clinch"). Analyzing the behavior of a single clinch is therefore essential for determining the behavior of a complete multi-clinch assembly.

This article is devoted to the study of the behavior of the clinch component in shear. Experimental, numerical and analytical aspects of the research are presented. First, a comparison between experimental and numerical results is carried...