初稳性高取值对柔性设计大型汽车运输船疲劳强度评估影响的研究

Study on Influence of Initial Metacentric Height for Fatigue Strength Assessment for Flexible Design of Large Pure Car and Truck Carrier

柔性设计大型汽车运输船具有型深大、甲板层数多、货舱区不设置横舱壁、甲板横向强构件和舷侧垂向强构件柔性连接等结构特征,造成了突出的疲劳强度问题。在现有的疲劳强度评估简化方法中,初稳性高GM取值对疲劳载荷、Weibull分布参数、过零频率都存在影响,而规范并没有针对GM取值有明确的要求,因此GM取值对汽车运输船的结构可靠性研究具有重要意义。论文依据挪威船级社规范,采用疲劳寿命评估简化计算方法,研究了GM取值对7800车汽车运输船疲劳寿命预测值的影响规律。这项研究对于非常规船型的结构疲劳性能评估方法研究具有一定的参考价值。

Large PCTC(pure car and truck carrier)based on flexible design principle is of structural characteristics such as large depth,multiple decks,cargo hold without transverse bulkhead,flexible connection between vertical side frames and deck transverse girders,which will easily result in serious fatigue damage.In the present fatigue strength assessment method,the value of GM(initial metacentric height)has influence on the fatigue load,Weibull’s distribution parameter and the zero crossing frequency.However,the specification does not make clear requirements for GM values in present norms.In the paper,according to DNV(Det Norske Veritas)specifications,influence of GM value on the fatigue life for a 7800 PCTC is analyzed based on a simplified fatigue calculation method.The result has a certain reference value for the research on the fatigue performance evaluation for unconventional ships.