Experimental methods to capture curing induced effects in adhesive bonded joints

The rapidly increasing use of structural adhesives, especially in the joining of automotive body structures has motivated various investigations of the effects of adhesive curing process on joints. The automotive-grade structural adhesives require heat curing, which, in the meantime, performs thermal loading on the substrates and causes undesirable effects in the joint. For example, the curing process results in complex residual stresses in the adhesive bond which are detrimental to the performance of the adhesive bond and thereby the automobile body structure, particularly the crashworthiness. To thoroughly evaluate such effects, this paper consists of two parts. The first part presents an innovative experimental method to characterize the thermal effects of the heat curing process on a multi-material single lap shear joint using digital image correlation. The second part of the study compares the performance of residual stress-induced joints against stress-free joints under tension loading at different strain rates. The proposed experimental method and the corresponding results from this study are expected to help comprehensively understand the adhesive joining process and its potential side effects on the automobile body structure.

Automated summary

The increasing use of structural adhesives in joining automotive body structures has led to investigations on the effects of adhesive curing process on joints. The heat curing process of the automotive-grade structural adhesives can result in undesirable residual stresses in the adhesive bond, affecting the performance of the joint. This study presents an innovative experimental method to characterize the thermal effects of heat curing process and compares the performance of residual stress-induced joints against stress-free joints under tension loading at different strain rates, aiming to comprehensively understand the potential side effects of adhesive joining on automobile body structure.