Thermal Stress in Aluminum-To-Composite Double-Lap Bonded Joints

Naveen Rastogi, Som R. Soni and Arvind Nagar

ABSTRACT

Thermal stresses in aluminum-to-composite, symmetric, double-lap joints are studied using a three-dimensional variational, finite element analysis technique. The joint configuration considers aluminum adherent in combination with four different unidirectional laminated composite adherents subjected to uniform temperature loading. When the free expansion of the joint was permitted the aluminum plate had much higher magnitude of the thermal stresses for the cases when the upper adherents were either boron/epoxy composite laminates as compared to the cased when the upper adherents were either glass/epoxy or the GLARETM laminates. When the joint was restrained against its free expansion in the in plane coordinate directions, the magnitudes of the in plane stress components in the lower aluminum adherent and the upper boron/epoxy adherent increased many fold. In this case both the joint and corners were found to be critical regions for debonding initiation.