The present-day interest in the use of composite-steel joints in primary
marine applications requires an in-depth knowledge of the fatigue
performance of thick adhesive joints. This paper reports on experimental
tests, quasi-static and fatigue, performed on unaged and aged
bi-material double strap joints with thick adhesive bondlines. The
specimens are monitored by Digital Image Correlation and Infrared
Thermography techniques to evaluate the types and extent of damage that
occur in the joint during fatigue loading. The S-N curve of the aged
joint is evaluated along with it's fatigue limit. It is found that the
unaged specimens fail due to cohesive damage, hackles and disbond at the
adhesive-adherend interface and the aged specimens failed due to
delamination within the composite. The specimens that survived fatigue
loading showed similar residual strength as specimens that were not
fatigue loaded.