Load rate effects on Interlaminar fracture toughness of composite materials

Paper presented to the 5th Annual Symposium on Graduate Research and Scholarly Projects (GRASP) held at the Hughes Metropolitan Complex, Wichita State University, May 1, 2009.Research completed at the Department of Aerospace Engineering, College of EngineeringThe energy dissipation due to the failure of composites is of particular interest for crash applications involving dynamic loading. Separation of layers or delamination which can occur in opening (mode-I) is one of the key failure mechanisms that dictates the energy absorption. In this investigation, the effects of load rate on the mode-I fracture behavior of laminated composites were studied using quasi-static experiments. The experiments were conducted on laminated beam type specimens with inserts to simulate delamination. The results showed an increasing trend on the fracture toughness for the corresponding increase in the crack extension rate for the Toray Carbon Unitape and scattered response for Newport Fiberglass