Mechanical Properties and Fracture Characterization of Cross-Linked PVC Foams

Abstract

The tensile stress-strain response and fracture behavior of cross-linked PVC foams have been characterized over a range of foam densities from 36 to 400 kg/m3. The foams were found to be nearly isotropic. Young’s modulus, yield strength and fracture toughness data were compared to micro-structural relations derived for open and closed-cell foams. The failure process and stress strain response were indicative of brittle material behavior. Short gage length tension specimens bonded to aluminum loading blocks showed a tensile strength that increased with decreasing gage length as a result of improved support of the cell-walls of the foam under constrained lateral deformation. The plastic zone size for each of the fracture specimens, estimated from the von Mises yield criterion, was small indicating quasi-brittle failure. Testing of scaled single edged notch bend (SENB) fracture specimens revealed a toughness that decreases with decreasing specimen size.