规则波和不规则波中船舶艉砰击及其振动响应的试验研究

在拖曳水池中对某船舶进行了艉砰击及其振动响应的试验研究.在规则波以及不规则波中的零航速、艉随浪情况下观察到了严重的艉砰击现象.试验数据分析表明,合成弯矩可以分成由波浪载荷引起的低频成分以及由砰击载荷引起的高频成分.由于严重艉砰击载荷的作用,发现在某次规则波试验中合成弯矩比波浪弯矩要大出44%,在3.24m不规则波中合成弯矩增加了43%.不规则波中的试验数据统计表明合成弯矩分布范围服从Weibull分布.推导了服从Weibull分布随机变量的短期概率极值预报公式,针对试验数据进行了预报.还讨论了试验数据分析中的不确定性问题.试验研究表明,对于艉部平坦肥大的船舶,在设计和使用中需要引起对艉砰击及其振动响应问题的重视.

Experimental Investigation of the Stern Slamming and Whipping in Regular and Irregular Waves

Model experiments on the stern slamming and whipping of a ship were carried out in a towing tank.Severe stern slamming was observed when the model was at zero speed in following waves both in regular and irregular waves. Experimental results show that the total Vertical Bending Moment can be divided into one low frequent component due to wave loads and one high frequent component due to whipping loads. Total VBM for one regular sea case increases 44% compared with wave component,and MTot increases 43% at a 3.24m irregular sea state because of severe whipping loads.Formulas for short-term prediction of extreme value of random variable following Weibull distribution are obtained. Uncertainties of test data analysis are discussed. It is necessary to pay attention to stern slamming and whipping problems for ships with flatter stern both in design and in service.