Analysis of Shear Wave Generation by Decoupled and Partially Coupled Explosions
SCIENCE APPLICATIONS INTERNATIONAL CORP SAN DIEGO CA
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The objective of this new project is to investigate the sources of shear wave generation by decoupled and partially coupled explosions, and the differences in shear wave generation between tamped and decoupled explosions, using data analysis and numerical modeling of decoupled and partially coupled explosions. During the first phase of this project, we focused on three theoretical mechanisms for generation of shear waves from decoupled and partially coupled explosions. The first mechanism is offset of the explosion from the center of the cavity, causing impact on the sides to vary in both amplitude and time. We worked out the general solution to this problem, and then performed calculations of an airshock propagating in the cavity and impacting the cavity wall. We find that the offset explosion acts like a dipole source and can generate significant shear waves with a modest offset from the center. The second physical mechanism is an explosion in an aspherical cavity, in this case a cylindrical tunnel. The third physical mechanism we considered is crack growth outside of a partially coupled explosion. We are investigating two types of crack distributions 1 small hydrofractures distributed broadly around the explosion in response to tensile stresses, and 2 generation of a smaller number of larger hydrofractures.
- Nuclear Explosions and Devices (Non-Military)