Experimental Model Update for Single Lap Joints

With the increasing trend toward lightweight assemblies, the designer has to face new NVH challenges. Particularly, various structural joints have a different impact on the vibration response of these assemblies, which should be numerically modelled since the early stage of the design. The goal of this work is to experimentally assess the accuracy of simplified finite element models for joints and to evaluate how model updating techniques can improve the model accuracy. Four different lap joint samples are considered, each of them constituted by two aluminum plates connected with a different technology: one epoxy adhesive, one toughened acrylic adhesive, one acrylic foam tape, and one bolted joint, which is assessed for multiple preload configurations. For each of these cases, an experimental modal analysis is performed, a finite element model with input parameters from the datasheet of the bonding method is set up, and finally these joint parameters are updated with respect to the experimental reference. We apply the same procedure on an industrial case: the adhesive connection between the tube and the bracket of an automotive shock absorber. It is shown that the initial finite element models generally show a good agreement with the experiments for stiff adhesives. However, for the more flexible adhesives, the model update offers a significant accuracy improvement which can be important to account for during the design.

Automated summary

This study aims to experimentally assess the accuracy of simplified finite element models for joints and evaluate how model updating techniques can improve accuracy. Experimental modal analysis and model updating were performed on different joint samples and an industrial case, showing that model updating significantly improves accuracy for flexible adhesives, which may be important to consider during the design process.