Accession Number:

ADA230180

Title:

Estimates of Shock Wave Attenuation in Snow

Descriptive Note:

Special rept.

Corporate Author:

COLD REGIONS RESEARCH AND ENGINEERING LAB HANOVER NH

Personal Author(s):

Report Date:

1990-10-01

Pagination or Media Count:

21.0

Abstract:

A simple momentum model, assuming that snow compacts to its final density at negligible stress, is used to estimate shock wave attenuation in snow. Four shock loading situations are examined a one-dimensional pressure impulse of finite duration and instantaneously applied pressure impulses for one-dimensional, cylindrical and spherical shock geometries. Calculations show that while a finite duration impulse is being applied, the shock pressure in snow is determined by the impulse pressure-time profile. After the pressure impulse has been applied, the one-dimensional shock pressure decay is the same as for an instantaneously applied pressure impulse and is proportional to the inverse square of the shock propagation distance. Hence, finite-duration pressure impulses delay the onset of shock attenuation in snow. This can result in more pressure attenuation near a shock source, where the positive phase duration of the shock is short, compared to shock waves farther from a source. Cylindrical waves have a maximum decay that is proportional to the inverse of the propagation radius to the fourth power 1Rto the fourth power, and spherical waves have a maximum decay that is proportional to 1R to the sixth power. Amplitude decay for cylindrical and spherical shock waves can vary from R-40-2, when R-R0R0 where R0 is the interior radius over which a pressure impulse per unit area is applied, to their maximum decay.

Subject Categories:

  • Snow, Ice and Permafrost

Distribution Statement:

APPROVED FOR PUBLIC RELEASE