Affiliation:
1. Department of Mechanical Engineering, University of Massachusetts Dartmouth, North Dartmouth, MA, USA
Abstract
An experimental study was performed to investigate damage sensing and fracture toughness of multifunctional conductive glass fiber composites under dynamic mode-I fracture loading. Carbon nanotubes (CNTs) were dispersed within the epoxy matrix using a shear mixing and sonicating process. An electrostatic wet flocking process was used to reinforce milled short PAN-based carbon fibers onto each of the layers of glass fiber fabric along the thickness direction in the composites. These layers of flocked fabric were stacked, and a vacuum infusion process was employed to fabricate the composites. The parametric study consisted of two carbon fiber lengths (80 μm and 150 μm) and two fiber densities (1000 fibers/mm2 and 2000 fibers/mm2) and was performed to investigate the damage sensing capabilities of a three-dimensional conductive network generated through CNTs and carbon fibers. A double cantilever beam (DCB) configuration was considered, and a modified Hopkinson pressure bar setup along with a high-speed camera was used to investigate dynamic fracture toughness of the composites. The piezo-resistance response of the composites during dynamic fracture was measured using a modified system of four probes. For comparison, composites were also characterized for fracture toughness and piezo-resistance under quasi-static fracture loading conditions. The addition of short, milled PAN-based carbon fibers significantly increased the fracture toughness of glass/epoxy composites. The piezo-resistance response of the composites was easily correlated with instances of sudden crack growth during static fracture loading.
Funder
Office of Naval Research
U.S. Department of Defense
National Science Foundation
Subject
Materials Chemistry,Mechanical Engineering,Mechanics of Materials,Ceramics and Composites