Influence of the nonlinearities in waves, ship-motions, and ship-structure-responses on the expected maximum load on the ship's life

2023 Fiscal Year Final Research Report

• Project/Area Number: 21H01538
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 24020:Marine engineering-related
• Research Institution: The University of Tokyo
• Principal Investigator: HOUTANI Hidetaka 東京大学, 大学院工学系研究科(工学部), 講師 (30636808)
• Co-Investigator(Kenkyū-buntansha): 高見 朋希 国立研究開発法人海上・港湾・航空技術研究所, 海上技術安全研究所, 主任研究員 (50586683) ; 松井 貞興 国立研究開発法人海上・港湾・航空技術研究所, 海上技術安全研究所, 主任研究員 (60734225) ; 小森山 祐輔 国立研究開発法人海上・港湾・航空技術研究所, 海上技術安全研究所, 研究員 (90805110)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: HOSM / FORM / 非線形波 / 極値推定 / 弾性模型船

Outline of Final Research Achievements

A time-domain nonlinear strip method for simulating ship response to nonlinearly evolving waves, called “NMRIW-II-HOSM”, has been developed. The numerical simulation of the response of a container ship to long-crested irregular waves showed that not only the body nonlinearity but also the wave nonlinearity can affect the extreme value distributions of the sagging moment. Furthermore, a method called HOSM+FORM was developed to estimate such extreme values of the ship response together with their probability of occurrence. The introduction of a surrogate model of the nonlinear ship response enables the extreme value estimation of the ship response to take into account the nonlinearities in both the wave and the ship response. This extreme value estimation method was verified by a tank experiment using aflexible acrylic ship model.

Free Research Field

船舶海洋工学

Academic Significance and Societal Importance of the Research Achievements

波の非線形発達が船体応答に及ぼす影響はまだまだ明らかでない中で、非線形発達する波の中での船体応答を計算することが可能な数値計算コードを国内で初めて開発した（国外でもわずかしか存在しない）。さらに、このような非線形波浪中の船体応答極値を確率的に推定する手法も初めて開発し、船舶・海洋構造物の設計への活用等、海上安全の実現に向けて意義のある成果と考える。