Failure loads of mechanical fastened pinned and bolted composite joints with two serial holes

Abstract

An experimental and numerical study has been carried out to investigate the first failure load and the bearing strength behavior of pinned joints of glass fiber reinforced woven epoxy composite prepregs with two serial holes subjected to traction forces by two serial rigid pins. In the experiments, a number of parameters such as the edge distance-to- upper hole diameter (E/D), the distance between center of two holes-to-hole diameter (K/D), and the width of the specimen-to-hole diameter (W/D) were varied. Each specimen configuration was analyzed using the finite element model. Generally, comparison between computed and experimental results for first failure load presented a good agreement. Also to see the effects of preload moments and sea water on the bearing strength of joints an experimental investigation was carried out. For this purpose, the specimens were tested under 3 and 6Nm preload moments for unimmersed condition. Other specimens held in sea water for 24h. Afterwards, the same experiments were performed to the immersed specimens. It was observed that the immersion of test specimens into sea water causes a decrease in the failure load without a preload moment. The test specimens under preload moments produce nearly the same bearing strength as unimmersed specimens.