Particle tracking-based in-situ computed tomography measurement technique for advanced analytics of adhesive bonds

Abstract

In the application field of adhesive bonding technology, the use of in-situ computed tomography (CT) opens up possibilities for detecting processes inside bonds that were hidden thus far. The present paper presents a successfully applied in-situ CT measurement technique, which allows the high-resolution measurement of displacements on the surface as well as within adhesive layers. The focus of the work was on the analysis of bulk specimen, bonded single-lap joints as well as butt joints under a stepwise increased load. In the experimental investigations, the specimens were stressed with technical strains ε and shears from 0.5% up to 25% and the resulting adhesive behaviour was observed in the form of measured displacements. Thus, in the analysis of bulk specimens, relaxation effects on the microscopic scale could be measured and visualized. Using single-lap joints and butt joints, both the displacements measured on the side face of the bondline and the displacements resulting within the adhesive volume could be measured and visualized at the highest resolution. In additional investigations, further potentially promising application examples could be shown, such as the supporting use of the in-situ CT measurement methodology for the derivation of characteristic values for the failure of bonded joints.