Nandika Anne D'Souza and Witold Brostow
Laboratory of Polymers and Composites, Department of Materials Science, University of North Texas, Denton, TX 76203-5308

A. C. Ramamurthy
Automotive Components Group, Ford Motor Co. 24300 Glendale Avenue, Detroit, MI 48239

Yingxia Wang, Robert L. Thomas, and Lawrence D. Favro
Department of Physics and Institute for Manufacturing Research, Wayne State University, Detroit, MI 48202

ABSTRACT

Thermal wave imaging combined with Stress Pattern Analysis by measurement of Thermal Emission (SPATE) is used to study the failure behavior of a polypropylene (PP) + ethylene propylene diene (EPDM) blend. Images corresponding to a propagating crack in a single edge-notched specimen at three rates of testing: 4 mm/min, 8 mm/min and 20 mm/min. Conversion to stress values is made through use of a thermoelastic function. It is found that in the 4 mm/min test the crack tip radii blunts rather than propagates with little initiation. Large scale necking precedes fracture. At 8 mm/min, some blunting occurs followed by rapid crack propagation. At 20 mm/min, rapid crack propagation occurs. The images are digitized to obtain the values of the temperatures at every point in the sample. Data corresponding to the plane of the propagating crack over the span of the test are presented.

*Polymer Eng. & Sci. 1996, 36, 194.