Low temperature and tightening torque effects on the failure response of bolted glass fiber/epoxy composite joints

Abstract

This article reports an experimental investigation on failure responses of single lap double serial fastener joints in glass fiber/epoxy composite laminates when subjected to low-temperature environment. The results of experiments, implemented at five different low-temperature levels ranging from 0℃ to −40℃, were evaluated in comparison with room temperature tests. Joints exhibited relatively higher load-carrying capacities with increased stiffness by decreasing temperature. In order to examine tightening torque effects at each temperature condition, bolts were fastened under M = 6 Nm and M = 0 Nm (finger tightened) torques. As expected, a greater amount of bearing load could be carried by the joints with pre-tightened fasteners. Furthermore, any reduction in temperature is observed to lift the effectiveness of tightening torque on the joint strength. Regardless of the temperature exposed, bearing mode, the most desirable failure type in mechanically fastened joints was monitored as the main failure mode.