Accession Number:

AD0420509

Title:

NEGATIVE EQUATION OF STATE AND SPALL CRITERIA.

Descriptive Note:

Rept. for May 62-June 63,

Corporate Author:

BOEING CO SEATTLE WASH

Report Date:

1963-09-01

Pagination or Media Count:

154.0

Abstract:

Several types of solids were subjected to high, one-dimensional, short-duration strains produced by the planar impact of flat plates accelerated either by electrically exploded metal foils or by an air gun. Time-to-spall measurements were made at room temperature on Plexiglas and aluminum. The critical tensile stress was found to depend on the time-duration of the pressure pulse in aluminum but not in Plexiglas. The critical spall threshold in Plexiglas was found to increase with increasing temperature 1 kilobar at room temperature, 1.5 kilobars at 68 C, 2 kilobars at 100 C. The Hugoniot equations of state for Plexiglas have been measured at 68 C and 100 C, and for chopped nylon phenolic at room temperature and at 100 C. The free surface velocity in chopped nylon phenolic, as well as in Plexiglas at sufficiently high velocity, was shown to drop off with distance at a much higher rate than predicted by simple hydrodynamic theory. As a result, a critical tensile stress cannot be defined in chopped nylon phenolic. Author

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE