The Effects of the Butterfly Joints on Failure Loads and Fatigue Performance of Composite Structures

The present study was designed to examine experimentally the effects of butterfly fitting clearances and different adhesives on the load carrying abilities of the composite structures joined via a butterfly-shaped joining component and the fatigue performance of the specimens joined by the best joint style obtained. Experiment specimens and butterfly-shaped locking components were cut from a composite plate by means of water jet. Fatigue experiments were conducted at the constant load ratio and at different maximum fatigue loads. To compare the fatigue performance, the fatigue experiments of the butt joints were also carried out. According to the experiment results obtained, it was determined that fatigue strengths of adhesively-bonded butterfly joints have a longer life span than those of the bonded butt joints under the same circumstances. The present study has made it possible that with the use of butterfly joining component, the earliest damage should occur on the butterfly and should have a longer service life with the repairs of the butterfly joining component.