本文選題：深水半潛式平臺 + 碰撞�。� 參考：《江蘇科技大學(xué)》2015年碩士論文

【摘要】：當(dāng)今世界上,海洋油氣資源的開發(fā)已經(jīng)具有了非常大的潛能,目前海洋工程領(lǐng)域,已逐步實現(xiàn)了由近海向遠(yuǎn)海乃至深海的發(fā)展,我國海洋/深海油氣資源特別豐富,其中的油氣資源儲備量大約是246億噸,占我國石油、天然氣資源總量的30%左右。在作業(yè)海域上,半潛式海洋平臺開展鉆井或采油時,在隨機(jī)復(fù)雜的海洋環(huán)境下,除了受環(huán)境載荷的時刻作用外,過往的船只、守衛(wèi)船、補給船等各種船舶由于航行操作過失或停靠被供給平臺時,風(fēng)、浪、流等環(huán)境載荷的作用,經(jīng)常不可避免的發(fā)生與平臺碰撞事故,并可能造成環(huán)境污染、結(jié)構(gòu)損壞、重大的經(jīng)濟(jì)損失、人員傷亡等一些災(zāi)難性后果。特別是在深水和超深水海域,由于海況一般更為惡劣,則碰撞事故更容易發(fā)生。本文為了分析隨機(jī)海洋環(huán)境載荷作用下,船舶與海洋平臺碰撞的外部動力學(xué)問題,利用非線性顯式有限元軟件ANSYS/LS-DYNA建立了半潛式平臺和供給船船尾的三維有限元模型,通過DYNA計算了船尾以2m/s速度垂直正碰半潛式海洋平臺立柱的工況,獲得了真實的碰撞力的時序結(jié)果。然后在此基礎(chǔ)上結(jié)合外部動力學(xué)原理,將真實的碰撞力導(dǎo)入到水動力軟件AQWA中,將半潛式平臺在碰撞力和風(fēng)、浪、流聯(lián)合作用下進(jìn)行時域耦合的水動力數(shù)值計算,得到了平臺運動響應(yīng)結(jié)果和不同系泊纜的受力情況。綜上,本文將對船舶與半潛式海洋平臺的碰撞進(jìn)行數(shù)值計算研究。本論文主要研究內(nèi)容包括:(1)進(jìn)行了供給船船尾和半潛式海洋平臺的模型化研究,其中半潛式海洋平臺建立整體有限元模型,考慮到其碰撞受損傷位置主要是立柱區(qū)域,對立柱部分進(jìn)行了詳細(xì)的建模,同時為了減少模型的計算機(jī)時,對浮筒及上殼體內(nèi)部做了大量的簡化處理,甲板以及甲板以上的結(jié)構(gòu)用一層加厚的甲板和質(zhì)量塊來代替,對于這些簡化部分的重量以及它們的重心位置,可以在結(jié)構(gòu)的對應(yīng)部分通過LS-DYNA來控制其密度的方法來調(diào)整。船尾方面則考慮到船尾的剛度相對海洋平臺立柱結(jié)構(gòu)大的多,故模型中船尾簡化為剛性模型,但計算結(jié)果相對保守。最終基于ANSYS軟件建立平臺和船尾的三維模型并劃分有限元網(wǎng)格,并在此基礎(chǔ)上利用非線性顯式有限元軟件LS-DYNA進(jìn)行碰撞模擬仿真。(2)應(yīng)用ANSYS/LS-DYNA顯式非線性動力商業(yè)軟件,采用Cowper-Symonds本構(gòu)物理模型,用附加水質(zhì)量方法對一艘5000t的補給船船尾以2m/s速度垂直撞擊半潛式海洋平臺立柱的例子進(jìn)行數(shù)值仿真,對立柱部分做重點分析,獲得了碰撞力的時序結(jié)果,部分關(guān)鍵時刻碰撞的應(yīng)力云圖,將碰撞力曲線不做任何簡化的加載到水動力模型上進(jìn)行水動力分析。水動力數(shù)值模擬分析主要有:頻域和時域計算兩部分。本文既應(yīng)用時域分析方法,又應(yīng)用頻域分析方法對海洋結(jié)構(gòu)物及其系泊系統(tǒng)在碰撞力作用下進(jìn)行水動力性能分析研究。(3)頻域分析結(jié)果主要表征海洋結(jié)構(gòu)物在各個不同頻率下的附加質(zhì)量系數(shù)和輻射阻尼系數(shù),還可以得到不同浪向下的運動響應(yīng)RAO、一階、二階波浪力和傳遞函數(shù)等。本文將不作任何簡化的碰撞力時程曲線導(dǎo)入到AQWA中,并借助水動力軟件AQWA-Line,采用三維勢流理論,對被碰撞的半潛式平臺進(jìn)行數(shù)值計算,得到相關(guān)的水動力參數(shù)。(4)時域分析方法主要是研究海洋結(jié)構(gòu)物及其系泊系統(tǒng)在一定海洋環(huán)境條件下其運動響應(yīng)和每根系泊纜的受力狀況,求證其是否能夠滿足規(guī)范的要求。本文采用AQWA-Drift水動力軟件對該半潛式平臺進(jìn)行時域耦合數(shù)值模擬,模擬計算了在碰撞力和風(fēng)、浪、流聯(lián)合作用下的平臺的運動響應(yīng)情況,不同系泊纜的受力情況。(5)由計算分析結(jié)果可見,由于碰撞位置發(fā)生在平臺左舷后側(cè)的立柱部位,有碰撞力作用的情況下,橫蕩、橫搖和首搖的變化非常大,說明碰撞力的大小、方向和變化趨勢對平臺的運動響應(yīng)有著直接和重要的影響,進(jìn)而影響其作業(yè)效率和安全性,因此研究在實際作業(yè)過程中的平臺碰撞是很有意義的。
[Abstract]:The development of marine oil and gas resources has been of great potential in the world today. At present, the marine engineering field has gradually realized the development from offshore to far sea and even deep sea. The marine / deep-sea oil and gas resources are very rich in our country, and the reserves of oil and gas are about 246 million tons, accounting for 30% of the total of China's oil and natural gas resources. Right. On the operating sea, when the semi submersible offshore platforms carry out drilling or oil production, in the random and complex marine environment, in addition to the time effect of the environmental load, the ships of the past, the guard ship, the supply ship and other ships are often unavoidable because of the environmental loads such as wind, waves, and streams due to the fault of the navigation operation or the supply platform. There are some catastrophic consequences such as environmental pollution, structural damage, major economic losses and casualties. Especially in deep water and ultra deep waters, the collision accidents are easier to occur because the sea conditions are generally worse. In order to analyze the load of the random marine environment, the ship and the ocean are analyzed. The three-dimensional finite element model of the semi submersible platform and the ship's tail is established by using the nonlinear explicit finite element software ANSYS/LS-DYNA. The working conditions of the stern with the vertical collision and semi submersible platform column of the ship's tail are calculated by DYNA, and the real time sequence results of the collision force are obtained. On the basis of the principle of external dynamics, the real collision force is introduced into the hydrodynamic software AQWA, and the hydrodynamic numerical calculation of the semi submersible platform is carried out in time domain coupled with the impact force, wind, wave and flow, and the results of the platform motion response and the force of different mooring cables are obtained. The main research contents of this paper are as follows: (1) a model study of the ship's stern and semi submersible offshore platform is carried out, in which the semi submersible offshore platform is established as a whole finite element model. Considering that the damage position of the offshore platform is mainly the vertical column area, the vertical column part is modeled in detail. In order to reduce the model computer, a large amount of simplification is done to the buoy and the interior of the upper shell. The deck and deck above are replaced by a thick deck and mass block. For the weight of these simplified parts and the position of their center of gravity, the density can be controlled by LS-DYNA in the corresponding part of the structure. At the end of the ship, the tail stiffness is much larger than that of the offshore platform column, so the tail of the ship is simplified as a rigid model, but the calculation results are relatively conservative. Finally, the three-dimensional model of the platform and the stern is established based on the ANSYS software and the finite element mesh is divided, and on this basis, the nonlinear explicit finite element software L is used. S-DYNA is used to simulate the collision. (2) using the ANSYS/LS-DYNA explicit nonlinear dynamic commercial software, using the Cowper-Symonds constitutive physical model, the numerical simulation of the vertical impact of the tail of a recharge ship on a semi submersible platform column at 2m/s speed is simulated with the additional water quality method. The time sequence result of collision force, the stress cloud of some critical moments, the collision force curve is not loaded into the hydrodynamic model to carry on the hydrodynamic analysis. The hydrodynamic numerical simulation analysis mainly includes two parts: frequency domain and time domain calculation. This paper applies the time domain analysis method and the frequency domain analysis method to the ocean junction. The hydrodynamic performance analysis of the structure and mooring system under the impact of the collision force. (3) the frequency domain analysis results mainly represent the additional mass coefficient and the radiation damping coefficient of the marine structures at various frequencies, and can also get the different wave motion response RAO, the first order, the two order wave force and the transfer function. Any simplified collision force time history curve is introduced into AQWA, and with the help of the hydrodynamic software AQWA-Line, the three-dimensional potential flow theory is used to calculate the collided semi submersible platform, and the related hydrodynamic parameters are obtained. (4) the time domain analysis method is mainly to study the transport of the marine structures and their mooring systems under certain marine environment conditions. The dynamic response and the force condition of each root system can prove whether it can meet the requirements of the standard. In this paper, the AQWA-Drift hydrodynamic software is used to simulate the time domain coupling of the semi submersible platform, and the dynamic response of the platform under the impact force and wind, wave and flow is simulated and the force conditions of different mooring cables are calculated. (5) The results show that the change of the size, direction and trend of the collision force has a direct and important influence on the motion response of the platform, which affects the efficiency and safety of the platform, as the collision position occurs on the post side of the platform side of the platform. Therefore, it is meaningful to study the platform collision in the actual operation process.
【學(xué)位授予單位】：江蘇科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TE95

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本文編號：1967202