This study presents a new statistical cubicization approach for predicting the stochastic response of offshore platforms subjected to a Morison-type nonlinear drag loading. Statistics of the original system are obtained from an equivalent nonlinear system, which is constructed by replacing the Morison drag force by a cubic polynomial function of the relative fluid-structure velocity, up to cubic order: A Volterra series expansion with a finite Fourier series representation is used to approximate the response of the equivalent system. Exact solutions are developed to express the Fourier coefficients of the second and third-order response as functions of the Fourier coefficients of the first-order relative fluid-structure velocity. Response statistics are then computed by ensemble averaging over a suitable number of realizations of the first-order Gaussian response. Response statistics up to the sixth order, computed for a variety of sea conditions, show accuracy and efficiency of the proposed method as compared to digital simulation.

Di Paola, M., Failla, G. (2002). Stochastic response of offshore structures by a new approach to statistical cubicization. JOURNAL OF OFFSHORE MECHANICS AND ARCTIC ENGINEERING-TRANSACTIONS OF THE ASME, 124(1), 6-13 [10.1115/1.1425395].

Stochastic response of offshore structures by a new approach to statistical cubicization

DI PAOLA, Mario;
2002-01-01

Abstract

This study presents a new statistical cubicization approach for predicting the stochastic response of offshore platforms subjected to a Morison-type nonlinear drag loading. Statistics of the original system are obtained from an equivalent nonlinear system, which is constructed by replacing the Morison drag force by a cubic polynomial function of the relative fluid-structure velocity, up to cubic order: A Volterra series expansion with a finite Fourier series representation is used to approximate the response of the equivalent system. Exact solutions are developed to express the Fourier coefficients of the second and third-order response as functions of the Fourier coefficients of the first-order relative fluid-structure velocity. Response statistics are then computed by ensemble averaging over a suitable number of realizations of the first-order Gaussian response. Response statistics up to the sixth order, computed for a variety of sea conditions, show accuracy and efficiency of the proposed method as compared to digital simulation.
2002
Di Paola, M., Failla, G. (2002). Stochastic response of offshore structures by a new approach to statistical cubicization. JOURNAL OF OFFSHORE MECHANICS AND ARCTIC ENGINEERING-TRANSACTIONS OF THE ASME, 124(1), 6-13 [10.1115/1.1425395].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10447/196216
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