Estimation of on-site directional wave spectra using measured hull stresses on 14,000 TEU large container ships

• Published in: Journal of marine science and technology Vol. 25; no. 3; pp. 690 - 706
• Main Authors: Chen, Xi, Okada, Tetsuo, Kawamura, Yasumi, Mitsuyuki, Taiga
• Format: Journal Article
• Language: English
• Published: Tokyo Springer Japan 01.09.2020; Springer; Springer Nature B.V
• Subjects: Automotive Engineering; Bending; Bending stresses; Cargo ships; Components; Container ships; Containers; Deformation; Directional spectra; Engineering; Engineering Design; Engineering Fluid Dynamics; Life cycles; Mechanical Engineering; Ocean waves; Offshore Engineering; Original Article; Pitch (inclination); Radar; Radar data; Rolling motion; Sea state; Sea states; Ship motion; Spectra; Stress history; Structural engineering; Structural safety; Water waves; Wave spectra; Measurement; Wave spectrum; Container ship; Double bottom bending stress; Vertical bending stress; Monitoring; Horizontal bending stress
• ISSN: 0948-4280; 1437-8213
• DOI: 10.1007/s00773-019-00673-w

Container ships are becoming larger and larger in recent years, requiring more evident assurance of the structural safety. To achieve this, it is essential to grasp actual stress history experienced by the ship structures to facilitate efficient design and maintenance, and to use them for optimal operation of the ship. To perform accurate estimation of these stress histories, it is important to precisely estimate the sea state which the ship is actually encountering. In this study, the authors studied a new method to estimate directional wave spectra using measured ship responses and discussed the following three cases. The first one is the combination of two components, vertical bending stress and horizontal bending stress. The second one is the combination of three components, vertical bending stress, horizontal bending stress and double bottom bending stress. The last one is the combination of three components of ship motion (pitch, roll and heave). The estimated sea states are compared with the ocean wave hindcast database and radar data, and then, accuracy and selection of appropriate combination of the responses are discussed.