Inverse estimation of stress responses at unmeasured locations on a large container ship under wave loads using a genetic algorithm

초록

The structural integrity of ships and offshore structures is a critical aspect of maritime engineering, as these structures are continuously subjected to complex and uncertain ocean wave loads. Accurately estimating the directional wave spectrum is essential for understanding the wave-induced responses of ships and ensuring their long-term structural performance. This study proposed a methodology for inverse estimation of stress responses at unmeasured locations of a large seagoing vessel utilizing ship response data measured during navigation. The directional wave spectrum around the vessel was estimated using the concept of wave buoy analogy, where measured stress responses on top of motion responses were also employed. The directional wave around the vessel is modeled as a ten-parameter bimodal spectrum and integrated with transfer functions to for ship response calculations. A genetic algorithm was introduced to solve the nonlinear optimization problem by minimizing discrepancies between predicted and measured responses in the encounter frequency domain. To account for Doppler effects, a wave-encounter frequency transformation is applied. Validation using a 13,000 TEU container ship numerical simulation demonstrates the method's accuracy and robustness, together with its potential for structural integrity management in real-world applications.

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