Introduction
Tolerances in the design of adhesive joints were determined and their influence on the mechanical behaviour of adhesively bonded steel joints under quasi-static and under cyclic loads was evaluated in this work.
Test preparation and test performance
The paper focuses on adhesive layer thickness, filling ratios, and surface treatments as the main production tolerances. They were varied at different levels. Four different bondline thicknesses, three different filling ratios, and two different surface treatments were investigated. The influence of tolerances was analysed on single-lap shear joints and peel joints. Toughened epoxy-based adhesives were used. Mechanical properties of bonded steel joints were investigated under static load and under cyclic load.
Results
In both load cases, adhesive layer thickness has the highest influence on the resulting shear strength. Peel strength decreased with reduced filling ratios.
Conclusions
The influence of adhesive layer thickness on fatigue could be predicted by shift factors. Furthermore, it was possible to describe the influence of production tolerances in an analytical way. This allows an evaluation of fatigue based on quasi-static tests.