Influence of bonded joint configuration on the cryogenic strength of double-lap composite-metal adhesively bonded joints

Abstract

The influence of bonded joint configuration on the strength of double-lap carbon fiber reinforced plastic (CFRP)-aluminum alloy bonded joints at cryogenic temperatures was investigated. The bonded joint configurations were double-lap bonded joints composed of CFRP inner and aluminum alloy outer adherends and aluminum alloy inner and CFRP outer adherends. Finite element method (FEM) analysis considering the temperature effect was conducted to evaluate the stress distribution in the adhesive layers of the bonded joints. The calculated peel and shear stresses near the edges of the adhesive layers with the metal inner adherends were lower than those with the composite inner adherends at cryogenic temperatures. The strength of the two types of bonded joints was obtained by tensile tests at room temperature, −50°C, and −150°C. The strength of the bonded joints with the metal inner adherends was higher than that with CFRP inner adherends at cryogenic temperatures because the thermal shrinkage of the metal inner adherends suppressed the stress at the adhesive layer edges.