Dimension-reduction of stochastic wave forces and probability density evolution analysis of wave-excited pile foundation. (1st January 2022)

• Record Type: Journal Article
• Authors: Liu, Zhangjun; Lü, Kangxuan; Liu, Zixin; He, Guangling
• Is Part Of: Ocean engineering. Volume 243(2022)
• Publication Date: 2022-01-01
• Subjects: Stochastic wave forces -- Morison's equation -- Dimension reduction -- Probability density evolution method -- Dynamic reliability assessment; Ocean engineering -- Periodicals; Ocean engineering; Periodicals; 620.4162
• DOI: 10.1016/j.oceaneng.2021.110159
• Languages: English
• ISSNs: 0029-8018

Abstract

Abstract: This paper discusses the reasonable description and simulation of the continuous stochastic wave force field at probabilistic level. Firstly, in order to overcome the challenge of high-dimensional random variables inherent in the conventional Monte Carlo sampling (MCS), the dimension-reduction (DR) simulations of stochastic processes are addressed based on both the non-deterministic spectral amplitude (NSA) method and the deterministic spectral amplitude (DSA) method. In the proposed method, merely one or two elementary random variables are required to describe the continuous stochastic wave force field at the level of probability density. Simultaneously, the simulation efficiency of the proposed scheme is significantly enhanced by employing the Fast Fourier Transform (FFT) algorithm. In addition, the DR simulations for continuous stochastic wave force field are conducted in accordance with the linear Morison's equation (LME) and the nonlinear Morison's equation (NLME). Finally, the stochastic wave force field acting on a single pile foundation is generated by the proposed method, followed by the refined linear dynamic analysis and reliability assessment of the employed single pile foundation combining the probability density evolution method (PDEM). The effectiveness, accuracy and engineering practicability of the DR methods are sufficiently illustrated by comparison with the MCS methods thereafter. The analysis results also show that the DR methods are of significance robustness in reliability assessment of offshore engineering structures. Highlights: The NSA- and DSA-based dimension-reduction representations are proposed. The stochastic wave forces are modeled by just several elementary random variables. The difference of LME and NLME on structural dynamic response is quantified. The methods of NSA and DSA on dynamic response analysis of structures are compared. The dynamic reliability assessment of the structure is conducted using the PDEM.