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To pursue better quality, there is a strong need for efficient and robust non-destructive testing methods for joining processes. A new approach has been proposed to detect loose bolted joints using acoustic waves. This method measures the dissipation of energy by recording the propagated waves on the surfaces of the joining partners next to the joint. The authors show a link between the torque moments applied to the bolt and the ability of the joint to transfer acoustic energy using both simulations and experiments. In this article, the method’s ability to detect variations of certain process parameters of the clinching process was investigated numerically. To this extent, results of FEM calculations of the joining process are used to simulate the non-destructive testing method. By varying parameters of the clinching model, their influence on the transmission of energy within the joint is studied.

Clinching is a cost-effective mechanical joining process used for metallic as well as nonmetallic materials. Destructive testing methods such as peel and tensile tests can be used for strength investigations of such joints. Additionally, by measuring the geometrical properties such as undercut, neck thickness, and final bottom thickness, the joint quality can be estimated. These methods are cumbersome and do not meet the time and cost efficiency requirements of industrial production. The harmonic analysis benefits from changes in vibration characteristics. In this paper, the structural response of a clinched joint, subjected to a dynamic displacement in order to introduce an acoustic wave testing method is studied. This is accomplished by using simulated joining processes. The approach of this paper is based on a transient dynamic finite element analysis, followed by a fast Fourier transform. The results are presented, together with an analysis of sensitivity to different process parameters.

The multi-material mix used nowadays requires several joints to establish a durable connection. It is necessary to test the joints without harming the parts to ensure the safety of the whole structure. Therefore, a new approach for a non-destructive testing method is presented and validated in this paper. The aim is to establish the testing routine as a fast and easy alternative to the few known non-destructive testing procedures. The approach measures the dissipation of energy by detecting the propagated waves on the surfaces of the joining partners next to the joint. After a short description and a theoretical insight in wave propagation, the experimental results will be substantiated by simulated findings. A bolted connection was chosen in the experiments due to the possibility to easily apply and check different torque moments. The simulation model was adapted and tested for different applied contact pressures. The general results show a detectable loss of energy that can be linked to different torque moments. Different effects are visible in the simulation and the experiments and will be described. The findings will be discussed and an short outlook will be given. The aim of proving the concept via experimental and simulated results was reached.