THERMAL-STRESSES IN ALUMINUM-TO-COMPOSITE DOUBLE-LAP BONDED JOINTS

Thermal stresses in aluminum-to-composite, symmetric, double-lap joint s are studied using a three-dimensional variational, finite element an alysis technique. The joint configuration considers aluminum adherend in combination with four different unidirectional laminated composite adherends subjected to uniform temperature loading. When the free expa nsion of the joint was permitted the aluminum plate had much higher ma gnitude of the thermal stresses for the cases when the upper adherends were either boron/epoxy or graphite/epoxy composite laminates as comp ared to the cases when the upper adherends were either glass/epoxy or the GLARE laminates. When the joint was restrained against its free ex pansion in the inplane coordinate directions the magnitudes of the inp lane stress components in the lower aluminum adherend and the upper bo ron/epoxy adherend increased many fold. In this case both the joint co rners were found to be critical regions for debonding initiation. (C) 1998 Elsevier Science Limited. All rights reserved.