超大型船载液舱晃荡冲击荷载的研究

发布时间：2018-07-07 22:08

本文选题：晃荡冲击荷载 + 大比尺模型实验　；参考：《大连理工大学》2014年硕士论文

【摘要】：船舶储液货舱正在向超大型容积发展,液舱在部分装载时,舱内液体晃荡问题会愈加显著。由晃荡引起的冲击荷载能够使舱壁结构产生较大的结构响应,甚至会导致液舱舱壁结构的破坏,带来巨大的经济损失。因此,船载液舱舱壁结构设计的一个关键力学问题是舱内晃荡冲击荷载的评估。室内大比尺晃荡模型实验是最能反映舱内液体晃荡物理过程的研究方法,也是应用最为广泛,且成果最显著的研究方法。为此本文建立了先进的晃荡模型实验研究方法,包括大吨位的六自由度运动平台,中大比尺的模型液舱,精确的荷载响应测量系统以及系统的后处理方法。大比尺晃荡模型实验研究方法的建立是准确评估液舱晃荡冲击荷载的基础。本文设计了一系列规则和不规则激励下的二维矩形舱和八边形舱的晃荡冲击荷载实验,分别从荷载机理和工程应用两个方面开展研究工作。荷载机理研究主要以晃荡冲击荷载的影响参数,时空分布及统计分析三个方面开展研究工作：舱内特殊物理现象对晃荡冲击荷载的影响；晃荡冲击荷载随液舱运动幅值,周期及液舱载液率的关系；晃荡冲击荷载随时间和空间的变化；晃荡冲击荷载的上升时间,持续时间和脉冲偏斜度等。研究结果表明：晃荡冲击荷载对液舱运动周期,幅值和载液率等参数非常敏感,且舱内液体不同的冲击物理现象会带来不同的冲击荷载形式；舱内液体主要冲击位置处以下区域垂直和水平方向都具有线性相关性；晃荡冲击荷载的上升时间和持续时间均为毫秒量级,且具有一定的时间属性。针对薄膜型液化天然气储液舱开展一系列面向工程应用的设计晃荡荷载研究：晃荡冲击荷载冲量和荷载冲击时间在结构设计时的应用；引起最大结构动响应的简化晃荡冲击荷载；原型液舱晃荡冲击荷载的研究等。研究成果表明：峰值较大的晃荡冲击荷载的上升时间位于能够液舱侧壁结构产生较大动响应的范围,而简化的晃荡冲击荷载形式可以为结构响应分析提供荷载参考；直接采用Froude相似得到的原型液舱冲击荷载结果偏于保守,需要开展进一步的研究工作。
[Abstract]:The ship's cargo tank is developing to a very large volume, and the liquid sloshing problem will become more obvious when the tank is partially loaded. The shock load caused by sloshing can make the bulkhead structure have a large structural response, and even lead to the destruction of the tank bulkhead structure, resulting in huge economic losses. Therefore, one of the key mechanical problems in the design of bulkhead structure is the evaluation of the impact load of sloshing in the tank. Indoor large scale sloshing model experiment is the most effective method to reflect the physical process of liquid sloshing in the cabin. It is also the most widely used and the most remarkable research method. In this paper, an advanced experimental method of sloshing model is established, which includes a six-degree-of-freedom motion platform with large tonnage, a model tank with medium to large scale, an accurate load response measurement system and a post-processing method of the system. The establishment of experimental research method for large scale sloshing model is the basis for accurate evaluation of tank sloshing impact load. In this paper, a series of experiments on sloshing impact load of two-dimensional rectangular cabin and octagonal cabin under regular and irregular excitation are designed, and the research work is carried out from two aspects of load mechanism and engineering application. The research of load mechanism mainly includes three aspects: the influence parameters of sloshing impact load, the spatial and temporal distribution and statistical analysis: the influence of special physical phenomena in cabin on the sloshing impact load, the sloshing impact load with the amplitude of tank motion, The relationship between period and liquid rate of tank; the change of sloshing impact load with time and space; the rising time, duration and pulse deflection of sloshing impact load. The results show that the sloshing impact load is very sensitive to the parameters such as the tank motion period, amplitude and liquid loading rate, and the different physical phenomena of the liquid in the tank will bring about different impact load forms. There is a linear correlation between vertical and horizontal direction at the main impingement position of liquid in the tank. The rise time and duration of sloshing impact load are both millisecond and have a certain time attribute. A series of engineering application oriented design sloshing load studies are carried out for membrane liquefied natural gas tank: the impulse of sloshing impact load and the application of load impact time in structural design; The simplified sloshing impact load which causes the maximum dynamic response of the structure, and the research of the sloshing impact load of the prototype tank, etc. The results show that the rising time of large peak sloshing impact load lies in the range of large dynamic response of tank sidewall structure, and the simplified form of sloshing impact load can provide load reference for structural response analysis. The results of impact load obtained directly from Froude similar tank are conservative and need further research.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U661

【参考文献】