Investigation of nonlinearity parameter B/A of saturated, unconsolidated marine sediments via a statistical approach

In this talk, we present a theory and the supporting experiment for the nonlinearity parameter B/A of saturated, unconsolidated marine sediments. The model is composed of the quadratic nonlinearity of the equivalent suspension of grains and the interstitial fluid and the nonlinearity resulting from the random grain contacts. To capture the random nature of grain contacts, the number of Hertzian contacts on each grain and the distribution of contact forces between grains are treated statistically. Predictions of B/A are compared with measurements performed with the finite amplitude insert-substitution (FAIS) method. Dependence of B/A on external compression and the incident sound pressure level is also discussed. [This work was conducted in the Unmanned Technology Research Center (UTRC) sponsored by the Defense Acquisition Program Administration (DAPA) and the Agency for Defense Development (ADD) in the Republic of Korea.]