Nonlinear Wave Propagation Study
Abstract
At the present time there still exists an element of uncertainty regarding the definition of an effective radius, which can be used to separate the nonlinear near-field regime adjacent to an explosion from the linear far- field seismic regime. This report presents results of a study of the response of Westerly granite to sinusoidal loading. The amplitude of transition from linearity to non-linearity can be defined. Results are compared to previous studies. Nonlinear effects were observed in a cylindrical test specimen of Westerly granite which was subjected to both flexural and torsional modes of resonant vibration. Nonlinear effects in shear are observed when the shearing strain exceeds approximately 0.000001, increasing slightly with increasing effective pressure. Nonlinear effects in flexure are also observed when the extension/compression strain exceeds 0.000001, also increasing very slightly with increasing effective pressure. These transition amplitudes probably represent a lower limit on the amplitude of transition from linear to nonlinear behavior for the primary elastic pulse propagating in the near-field of an explosion. Using these measurements it is not possible to determine whether the nonlinear effects observed in flexure are primarily an extensional or compressional feature. This is a critical issue and in future studies we will attempt to examine the constitutive properties of rocks in both tension and compression under moderate to low amplitude conditions.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 31, 1984
- Accession Number
- ADA147011
Entities
People
- B. R. Tittmann