Strain-Path Modeling for Geo-Materials.
Abstract
The explosions that most concern us all have effects known mainly by calculation. Since the calculations' credibility influences the cost and scope of deterrence, reliable numerical prediction of explosion-effects is a long-sought goal. For free fields, flaws in stress-strain relations limit the accuracy of predictions: such relations are hard to establish for specific geo-materials and admit a very wide range of fields. However, the kinds of deformation occurring in free fields depend more on burst geometry than on material properties. In particular, for contained, nearly spherical bursts - the basic events in nuclear monitoring - the paths traced in strain space by deforming material elements (''strain paths'') have shapes and orientations (''patterns'') that vary little with medium. Also, a) the patterns form a simple set, b) at a given strain amplitude they are not diverse, and c) hardware is at hand for stress measurement along them in the laboratory and (probably) in situ. Hence, it now appears feasible to obtain by measurement the stress-strain curves needed for reliable prediction of seismic sources. A subset of the same curves also prevails on a sizable, downgoing part of the field produced by a surface burst. Further, while paths are more complex and variable near the surface, they may still form a set small enough for stress-strain measurement - through that will not be so if full control over plane strain, including axis-rotation, is needed.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 07, 1984
- Accession Number
- ADA154378
Entities
People
- J. G. Trulio