1991 Fiscal Year Final Research Report Summary
Probabilistic Approach to the Estimation of Seamargin
| Project/Area Number |
01850099
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| Research Category |
Grant-in-Aid for Developmental Scientific Research
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| Allocation Type | Single-year Grants |
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| Research Field |
船舶抵抗・運動性能・計画
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| Research Institution | University of Osaka Prefecture |
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Principal Investigator |
HOSODA Ryusuke University of Osaka Prefecture Department of Naval Architecture Professor, 工学部, 教授 (30081392)
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| Co-Investigator(Kenkyū-buntansha) |
KUNITAKE Yoshikuni Mitsui Engineering & Shipbuilding Co. Ltd. Manager, 特機システム部, 部長
YAMADA Tomoki University of Osaka Prefecture Department of Naval Architecture Assistant, 工学部, 助手 (90240027)
KISHI Mituo University of Osaka Prefecture Department of Naval Architecture Lecturer, 工学部, 講師 (00145814)
NAITO Shigeru Osaka University Department of Naval Architecture and Offshore Engineering Assoc, 工学部, 助教授 (20093437)
NAKAMURA Shoichi Osaka University Professor Emeritus, 名誉教授 (60028909)
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| Project Period (FY) |
1989 – 1991
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| Keywords | Seamargin / Probabilistic Approach / Operation Profile / Nominal Speed Loss / Performance Assurance / Probability Density Function |
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| Research Abstract |
In this project, the so carred "SEAMARGIN" that has been understood as the design margin or design allowance is investigated. The conventional seamargin was studied from the viewpoint of design engineering and as pointed out that it as not the exact design allowance.
A ne concept of seamargin based on the probabilistic approach is proposed. The definition of the new seamargin is the power allowance of main engine to cover the probability of keeping prescribed ship speed. The decrease of ship speed in an actual seaway is represented by the sum of speed loss classified into(1)long-term 'Aging Effect', (2)NEddle-range 'Fouling Effect' and(3)short-term 'Weather Effect'. These effects are discriminated from each other under the assumption that each effect is a random variable of realizing independently.
After estimating the probability density function of each effect, the probability density function of speed loss and ship speed in an actual seaway are estimated by the convolution integral of the probability density functions. The probability exceeding the specified threshold design speed is estimated and evaluated.
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