Strength Prediction of Adhesively Bonded Lap Shear Joints at Elevated Temperatures

This study presents an investigation into the strength prediction of adhesively bonded single lap shear joints subjected to elevated temperatures, with a focus on capturing the adhesive response beyond the glass transition temperature (Tg). Finite element analysis with Ansys was used to simulate the mechanical behavior of single lap shear joints made of Aluminum 6061 T6, with a thickness of 1.5 mm substrates and Henkel LOCTITE EA 7000 structural adhesive. This epoxy adhesive has excellent moisture and corrosion resistance in high humidity environments with a minimal reduction in mechanical properties. The simulations incorporated temperature-dependent material response to predict joint strength under thermal and mechanical loading. Experimental validation was conducted through single lap shear tests at temperatures ranging from ambient to above the adhesive’s Tg, highlighting the agreement between simulated and experimental results. The test specimens were made according to ASTM D1002. The results show a drop in the joint strength above the glass transition temperature. The observed drop in could be attributed to the thermal degradation and oxidation in the adhesive which, in turn, reduces its adhesion and cohesion properties. The findings highlight the critical influence of temperature on adhesive performance and joint's structural integrity, providing valuable insights for designing reliable bonded structures at elevated temperatures.