Studies on Vibration Response, Damping Characteristics and Fatigue Strength of Ship Structure

船舶结构振动响应、阻尼特性及疲劳强度研究

• 批准号: 61302051
• 负责人: MATSUURA Yoshikazu
• 金额: $ 4.86万
• 依托单位: Osaka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Co-operative Research (A)
• 财政年份: 1986
• 资助国家: 日本
• 起止时间: 1986 至 1987
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-61302051/
• 关键词: damping characteristics; logarithmic decrement; local vibration; fatigue limit; random loading; 振動応力; 振動応答; 減衰特性; 疲労亀裂; 切欠き; 共振

Prevention of ship vibration is an important problem, because excessive vibration on a ship is uncomfortable for her passengers and crew and often causes fatigue damages in the structural members. Therefore, studies on damping characteristics and fatigue strength of ship structural members are necessary.Forced bending vibration experiments were carried out on the steel beams of rectangular cross section with a number of sprung mass. The experimental results showed the large value of logarithmic decrement for the beams mentioned above compared with beams without sprung mass. So it is concluded that the local vibration of the substructures of a ship will be useful in reducing the resonant vibration amplitude.Studies on fatigue strength of ship structural members showed the following results. The value of fafigue limit decreases under random loading condition, to which ships are subjected during service period. So there is possibility that fatigue damge for structural members with high elastic stress concentration factor will be accumulated under random loading condition. A study on fatigue strength of aft structure of a ship was also carried out. Some cracks were found at the corner of frame connection in the aft peak tank of a Ro-Ro ship and cause of these damages was due to the resonance between natural vibration of aft peak tank and propeller surface force.

防止船舶振动是一个重要的问题，因为船舶上的过度振动会给乘客和船员带来不舒服的感觉，并且常常会导致结构构件的疲劳损坏。因此,对船舶结构构件的阻尼特性和疲劳强度进行研究十分必要。对带有多个簧载质量的矩形截面钢梁进行了受迫弯曲振动试验。实验结果表明，与无簧载质量梁相比，上述梁的对数衰减值较大。因此得出结论，船舶下部结构的局部振动将有助于降低共振振幅。船舶结构件疲劳强度的研究表明了以下结果。船舶在服役期间所承受的随机载荷条件下，疲劳极限值会降低。因此，具有高弹性应力集中系数的结构构件在随机加载条件下有可能积累疲劳损伤。还开展了船舶艉部结构疲劳强度研究。某滚装船尾尖舱骨架连接角部发现部分裂纹，其损坏原因是后尖舱自振与螺旋桨表面力共振所致。