面向储舱结构设计的晃荡冲击荷载实验研究

摘要

薄膜型船载液化天然气储舱设计中的一个关键力学问题是对液体晃荡引起的冲击荷载的评估。晃荡冲击载荷主要包括晃荡冲击荷载的幅值，上升和持续时间以及荷载三角脉冲的偏斜度等参数。室内大比尺晃荡模型实验是评估晃荡冲击荷载的有效方法。以二维矩形液舱为模型，在大吨位六自由度运动平台开展了一系列不规则激励下的晃荡冲击荷载实验研究。研究结果表明：由于液体与气体的相互作用，导致晃荡冲击荷载具有幅值较大且冲击上升时间较短的特点，可能导致舱壁产生较大的响应。采用统计学的方法分析了晃荡冲击荷载的参数；此外，定量地提出了长期不规则激励下，由荷载峰值、上升和持续时间以及偏斜度的组成的三角脉冲荷载模型，该模型可为储舱舱壁结构设计和有限元分析提供荷载参考。%Sloshing impact pressure is a key issue in the structural design of the membrane type Liquefied Nature Gas (LNG)carriers.The parameters of sloshing impact load includes its magnitude,rise time,duration and skewness. Experimental investigation on a large-scaled sloshing model is the most reliable approach to determine impact loads.A series of tests on a 2D rectangular tank subjected to irregular excitations were performed on a hexapod test rig.The experimental results show that due to the interaction between liquid and gas,the peak pressure exhibits large magnitude and short rise time,which might induce large structural dynamic response.The key parameters of sloshing impact load were analyzed by using a statistical method.An idealized triangular impact pressure was introduced as a quantitative long-term irregular excitation to provide a simplified model of the impact load which contains all the essectial parameters of magnitude,rise time,duration and skewness of the impact pressure.This gives a reference to the structural design of LNG tanks.