Effects of geometric parameters on the failure behavior of mechanically fastened chopped carbon fiber tape reinforced thermoplastics

Abstract

In the present study, the failure characteristics of mechanically fastened ultra-thin chopped carbon fiber tape reinforced thermoplastics (UT-CTT) have been investigated. Failure process, failure modes, and failure strength were investigated under different fastening types (pin-loaded and bolt-loaded), tightening torques, and geometric ratios (edge-distance-to-hole diameter and width-to-hole diameter). A three-dimensional X-ray scanning system and digital microscope were employed for fractographic analysis to reveal the failure process of bearing specimens. The results indicate that specific progressive failure occurs later than first peak load, and the main damage patterns of bearing failure are brittle fracturing and local buckling. Bolt fastening clamping torque could suppress the bearing failure and lead to 66.7% increase in bearing strength when the fastening type varied from pin- to bolt-loaded. An increase in the geometric ratios leads to a slight increase in strength of pin-fastened specimens, and a significant increase in that of in bolt-fastened specimens.