舶用プロペラ翼の疲労設計

概要

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A study has been carried out concerning the design stress of marine propellers made of Mn bronze and Ni-Al bronze considering the fatigue strength at 10<SUP>9</SUP> cycles.The fatigue strength up to 10<SUP>8</SUP> cycles and the crack propagation characteristics of the materials were obtained in laboratory tests conducted under the same condition as full-scale propellers in service, and these test data were utilized in the study. The test data were analysed statistically and calculated according to fracture mechanics. The S-N curve which is necessary for the fatigue design could be obtained through this procedure. The relation between the design stress and the design life, which is dependent on each kind of vessel and the degree of safety, was established by applying Miners rule to the design S-N curve and the stress frequency distribution model which coincided well with the measured data on vessels in service. It is becoming possible for us to have a near satisfactory level of the design stress through this study, if the stress frequency distribution can be obtained for each kind of vessel in various service conditions.
社団法人日本マリンエンジニアリング学会の論文