The effect of preload on failure response of glass-epoxy laminated composite bolted-joints with clearance

In this study, the effect of preload moments on failure response of glass-epoxy laminated composite bolted-joints with bolt/hole clearance was investigated. To evaluate the effects of bolted-joint geometry and stacking sequence of laminated plates on the bearing strength and failure mode, parametric analyses were performed, experimentally. Two different geometrical parameters, edge distance-to-hole diameter ratio (E/D) and plate width-to-hole diameter ratio (W/D), were examined. For this reason, the E/D ratio was selected from I to 5, whereas the W/D ratio was chosen from 2 to 5. Besides, preload moments were applied as 0, 3 and 6 Nm. Due to the estimating material parameters effect, laminated plates were oriented as three different groups, [0 degrees/0 degrees/90 degrees'/90 degrees],, [45 degrees/45 degrees/-45 degrees/-45 degrees and [60 degrees/60 degrees/-60 degrees/-60 degrees](s),, symmetrically. The experiments were also performed under a clearance for the diameters of the bolt and the circular hole for 5 and 6 mm, respectively. Experimental results showed that failure mode and bearing strength are strictly affected by the magnitude of preload moments. Additionally, if material and geometrical parameters of composite bolted-joints are changed, the failure response is completely influenced by this change.