RESPONSE STATISTICS OF OCEAN STRUCTURES TO NON-LINEAR HYDRODYNAMIC LOADING PART II: NON-GAUSSIAN OCEAN WAVES

✍ Scribed by N. Moshchuk; R.A. Ibrahim

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 583 KB
• Volume: 191
• Category: Article
• ISSN: 0022-460X
• DOI: 10.1006/jsvi.1996.0109

✦ Synopsis

In this second part, the response statistics of ocean elastic systems to non-linear hydrodynamic loading represented by a non-Gaussian random process are considered. The non-Gaussian process is generated from a non-linear filter excited by a white noise process. The filter non-linearity is represented by a gradient of a potential function where an exact closed form solution of the stationary probability density exists. The filter non-linearity is selected such that its response probability density function exhibits the skewness feature of ocean waves. In order to estimate the filter power spectrum, a joint probability density function of the filter response co-ordinates at two different times is derived, using an orthogonal expansion technique together with the Fokker-Planck equation. This process yields a first order differential equation governing the time evolution of the filter response statistics. This equation forms an infinite hierarchy of coupled equations which are solved up to rank 10. The power spectra of the filter are obtained for different filter and excitation parameters. The response statistics of a linear elastic structure subjected to non-Gaussian non-linear hydrodynamic forces are determined using the stochastic averaging method and, alternatively, the orthogonal expansion method.