Session: 07-05 -01 Ice Model Tests

Submission Number: 180266

Recovering Environmental Loads From Force-Response Measurements of Offshore Structures 

Dynamic amplification that is associated with structural resonance usually occurs when an ocean structure is subjected to dynamic loading. The phenomenon presents a challenge in recovering the external load from the measured structural response of offshore assets. In this paper, we systematically examine several techniques to derive the environmental load based on recorded force response using a laboratory dataset collected in an ice tank for studying wave-ice-structure interactions. Two families of approaches are compared: (i) system dynamics-based method (physical filtering), and (ii) signal-processing methods, including wavelet transforms and empirical mode decomposition (EMD) with/without fast Fourier transform (FFT) pre-processing. Comparative analysis shows that the physical filtering generally performs better than other approaches. In contrast, wavelet tends to introduce unwanted dips prior to impact load. On the other hand, EMD is susceptible to noise, and EMD+FFT sometimes removes less significant impact load. Furthermore, the influence of finite-difference numerical differentiation for evaluating time derivates, which is involved in physical filtering, on retrieving applied load is investigated by: (1) reproducing the force response using system dynamic equations, (2) comparing with an alternative method, piece-wise smooth spline, to obtain time derivatives and hence external loads. The results presented in this work provide practical guidance for selecting load-identification workflows across a range of transient hydrodynamics and structural impact scenarios, and for integrating inverse filtering into structural health monitoring and digital-twin pipelines in offshore and marine engineering applications.

Presenting Author: Hongtao Li The University of Tokyo

Presenting Author Biography: Dr. Hongtao Li currently works as a specially appointed researcher at the University of Tokyo.

Authors:

Hongtao Li The University of Tokyo
Ersegun Deniz Gedikli University of Hawaiʻi at Mānoa
Zhengshun Cheng Shanghai Jiao Tong University
Junji Sawamura The University of Osaka
Raed Lubbad Norwegian University of Science and Technology
Wenjun Lu Norwegian University of Science and Technology
Takuji Waseda The University of Tokyo