ASA 130th Meeting - St. Louis, MO - 1995 Nov 27 .. Dec 01

1pPA7. Detailed observation of the complete fracture process of brittle carbon foam.

L. C. Krysac

J. D. Maynard

Dept. of Phys., Penn State Univ., 104 Davey Lab., University Park, PA 16802

Using wideband transducers, we have observed the acoustic signals produced by individual bond breaking events during the fracture of open cell brittle carbon. The complete fracture process, beginning with intermittent precursor bursts of small numbers of bonds breaking, and ending with the final rupturing catastrophic event, has been recorded with 20-MHz pinducers and a 400-Megasample/s digital oscilloscope. The statistics of the precursors, etc., including the force applied at any time during the fracture process, have been acquired, related to the acoustic record, and compared with the predictions of the random fuse model for the fracture of brittle material. The role of dynamics and stress waves affecting the fracture of real materials, which is not accounted for in the random fuse model, will be discussed.