Open AccessElastic radiation from explosively loaded ellipsoidal cavities in an unbounded medium
Author(s) -
Glenn L. A.,
Ladd A. J. C.,
Moran B.,
Wilson K. A.
Publication year - 1985
Publication title -
geophysical journal of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0016-8009
DOI - 10.1111/j.1365-246x.1985.tb01361.x
Subject(s) - ellipsoid , geology , radiation , geophysics , physics , mechanics , geodesy , optics
Summary Elastodynamic calculations were made to determine the radiation spectra from explosively driven ellipsoidal cavities in an unbounded medium. A finite element code was used to compute the displacements on the cavity surface and the integral representation theorem was then invoked to find the displacements in the far field. The method was applied to ellipsoids with 3 : 1 and 10 : 1 aspect ratios and the results were compared to the analytic solution for a sphere of equal volume. Both the peak amplitude and the spectrum of the particle velocities were found to be strongly dependent on direction. For example, along the major axis of the 10:1 ellipsoid, the peak amplitude of the radial velocity component is approximately 7.5 times smaller than along the minor axis, and the frequency at which the peak occurs is 4 times smaller. These results are of some importance in the potential use of large cavities for decoupling underground nuclear explosions since it may be possible to orient similar cavities in such a way as to mitigate, at least in certain directions, the predicted reduction of the decoupling factor at high frequencies.