Accession Number : AD0648214

Title :   INERTIAL, VISCOUS, AND PLASTIC EFFECTS IN HIGH SPEED IMPACT,

Corporate Author : GENERAL ELECTRIC CO PHILADELPHIA PA MISSILE AND SPACE DIV

Personal Author(s) : Riney,T. D. ; Chernoff,P. R.

Report Date : NOV 1961

Pagination or Media Count : 50

Abstract : A visco-plastic model for hypervelocity impact is proposed which takes into account inertial, viscous, and plastic effects. This is accomplished by introducing a viscosity factor, a dynamic yield stress, and incorporating these into the compressible fluid equations. From an examination of the resulting system of equations several dimensionless parameters are found which control the relative importance of the three effects at the various stages of the cratering process. The inertial effect is important throughout the early stages while the strength of the medium is dominant during final stages. Immediately after impact the viscous effect is large in the zone near contact interface. Its magnitude decreases as the strain-rate gradient decreases, but it may remain important throughout the flow process. In the absence of definitive data in the hypervelocity impact regime, computations are performed on a one-dimensional model in which the values of the viscosity factor and yield stress are varied. The above qualitative conclusions are verified, amplified, and related to the qualitative model of crater formation that has evolved from experimental studies in which the actual cratering process has been remonitored. It is found that all three effects are significant. (Author)

Descriptors :   (*HYPERVELOCITY PROJECTILES, *IMPACT), (*CRATERING, HYPERVELOCITY PROJECTILES), VISCOSITY, PLASTIC PROPERTIES, STRESSES, MATHEMATICAL ANALYSIS

Subject Categories : Armor

Distribution Statement : APPROVED FOR PUBLIC RELEASE