本文選題：晃蕩沖擊荷載 + 大比尺模型實驗��； 參考：《大連理工大學》2014年碩士論文

【摘要】：船舶儲液貨艙正在向超大型容積發(fā)展,液艙在部分裝載時,艙內(nèi)液體晃蕩問題會愈加顯著。由晃蕩引起的沖擊荷載能夠使艙壁結(jié)構(gòu)產(chǎn)生較大的結(jié)構(gòu)響應,甚至會導致液艙艙壁結(jié)構(gòu)的破壞,帶來巨大的經(jīng)濟損失。因此,船載液艙艙壁結(jié)構(gòu)設(shè)計的一個關(guān)鍵力學問題是艙內(nèi)晃蕩沖擊荷載的評估。 室內(nèi)大比尺晃蕩模型實驗是最能反映艙內(nèi)液體晃蕩物理過程的研究方法,也是應用最為廣泛,且成果最顯著的研究方法。為此本文建立了先進的晃蕩模型實驗研究方法,包括大噸位的六自由度運動平臺,中大比尺的模型液艙,精確的荷載響應測量系統(tǒng)以及系統(tǒng)的后處理方法。大比尺晃蕩模型實驗研究方法的建立是準確評估液艙晃蕩沖擊荷載的基礎(chǔ)。本文設(shè)計了一系列規(guī)則和不規(guī)則激勵下的二維矩形艙和八邊形艙的晃蕩沖擊荷載實驗,分別從荷載機理和工程應用兩個方面開展研究工作。 荷載機理研究主要以晃蕩沖擊荷載的影響參數(shù),時空分布及統(tǒng)計分析三個方面開展研究工作：艙內(nèi)特殊物理現(xiàn)象對晃蕩沖擊荷載的影響；晃蕩沖擊荷載隨液艙運動幅值,周期及液艙載液率的關(guān)系；晃蕩沖擊荷載隨時間和空間的變化；晃蕩沖擊荷載的上升時間,持續(xù)時間和脈沖偏斜度等。研究結(jié)果表明：晃蕩沖擊荷載對液艙運動周期,幅值和載液率等參數(shù)非常敏感,且艙內(nèi)液體不同的沖擊物理現(xiàn)象會帶來不同的沖擊荷載形式；艙內(nèi)液體主要沖擊位置處以下區(qū)域垂直和水平方向都具有線性相關(guān)性；晃蕩沖擊荷載的上升時間和持續(xù)時間均為毫秒量級,且具有一定的時間屬性。 針對薄膜型液化天然氣儲液艙開展一系列面向工程應用的設(shè)計晃蕩荷載研究：晃蕩沖擊荷載沖量和荷載沖擊時間在結(jié)構(gòu)設(shè)計時的應用；引起最大結(jié)構(gòu)動響應的簡化晃蕩沖擊荷載；原型液艙晃蕩沖擊荷載的研究等。研究成果表明：峰值較大的晃蕩沖擊荷載的上升時間位于能夠液艙側(cè)壁結(jié)構(gòu)產(chǎn)生較大動響應的范圍,而簡化的晃蕩沖擊荷載形式可以為結(jié)構(gòu)響應分析提供荷載參考；直接采用Froude相似得到的原型液艙沖擊荷載結(jié)果偏于保守,需要開展進一步的研究工作。
[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.
【學位授予單位】：大連理工大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：U661

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