1991 Fiscal Year Final Research Report Summary
Studies of Ship Structural Design Based on Reliability Engineering
| Project/Area Number |
01302034
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| Research Category |
Grant-in-Aid for Co-operative Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
船舶構造・建造
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| Research Institution | The Univeristy of Tokyo |
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Principal Investigator |
OHTSUBO Hideomi The University of Tokyo, Faculty of Engineering, Professor, 工学部, 教授 (20011132)
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| Co-Investigator(Kenkyū-buntansha) |
NOMOTO Toshiharu The University of Tokyo, Faculty of Engineering, Professor, 工学部, 教授 (80011170)
MUROTSU Yoshisada The University of Osaka Prfescture, College of Engineering, Professor, 工学部, 教授 (50081386)
NOBUKAWA Hisashi The University of Hiroshima, Faculty of Engineering Professor, 工学部, 教授 (60034344)
GODA Kunio The University of Tsukuba, Institute of Engineering Mechanics, Professor, 構造工学系, 教授 (40134209)
NAGAMOTO Ryuichi The University of Tokai, Faculty of Oceanography, Professor, 海洋学部, 教授
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| Project Period (FY) |
1989 – 1991
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| Keywords | weight-optimal reliability-based design / damage factor / thin-walled beam / large deformation / longitudinal side frames / failure mode / importance factor of members / structural panel |
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| Research Abstract |
The Present method is compared with the existing optimal design method based only on safety factors. Numerical simulation reveals that the present method leads to lighter structure with the same reliability index. The fatigue strength design procedure has been formulated, and reliability engineering is introduced to the procedure. Then, fatigue damages of ship structures are analyzed by these, and criteria for a damage factor and safety index are proposed for these procedures. The finite element program is developed for largely deformed elastoplasticity, and the effects of the utilized constitutive equation on numerical solutions are discussed.
Also, the experiments of thin rectangular plate reinforced by L-shaped ribs under the action of bending are carried out to investigate large deformation behaviors, and compared with the finite element solutions.
The fatigue strength of the longitudinal side frames has been assessed under the estimation of wave loads applied to ship sides in irregu
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lar waves, and the effectiveness of this assessment is verified in comparison of analyses of actual ship side damage occurring at sea. The method has been developed for performing reliability analysis of ship structures based on ultimate strength, which automatically generates relevant failure modes and their equations by using a matrix method and a plastic node method.
Structural reliability assessments are carried out by using the method in which probabilistic collapse analysis and failure mode analysis are combined. Effects of some design parameter alteration on structural reliability are also discussed through parametric studies.
Reliability analysis of compressive collapse strength for ship structural panels are taken into consideration here. Probability of failure for deck plates and bottom plates are calculated. As for bottom plates which are subjected to not only compressive in-plane load but also lateral water pressure, it becomes clear that collapse buckling modes change.
Numerical method for evaluating a reliability of finite element analysis has been established. The method was applied in ship structure analysis. An expert system aiding optimal structure design was coded. Several techniques have been added to a knowledge base in order to consider reliability. Less
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