發(fā)布時(shí)間：2018-03-16 06:44

  本文選題：魚雷錨　切入點(diǎn)：貫入速度　出處：《大連理工大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：如今世界上很多國家的油氣勘探重點(diǎn)由淺海向深海轉(zhuǎn)移,而安全穩(wěn)定的系泊基礎(chǔ)對于大型的深水油氣勘探設(shè)備非常重要。魚雷錨是一種新型高承載力的深水系泊基礎(chǔ),已應(yīng)用到FPSO等設(shè)備的系泊系統(tǒng)中,經(jīng)過實(shí)際工程驗(yàn)證,完全滿足海上設(shè)施的系泊要求。本文針對魚雷錨安裝的兩大過程進(jìn)行模擬計(jì)算,包括水中加速運(yùn)動(dòng)過程和貫入海床土層過程。文中詳細(xì)分析了魚雷錨及其錨鏈在水中運(yùn)動(dòng)時(shí)的受力情況,給出數(shù)學(xué)模型并進(jìn)行數(shù)值計(jì)算,得到魚雷錨釋放高度與初始貫入速度之間的關(guān)系。同時(shí)利用Abaqus建模對該過程進(jìn)行數(shù)值模擬,將所得結(jié)果與Matlab計(jì)算結(jié)果進(jìn)行比較分析,得到魚雷錨水中運(yùn)動(dòng)的一般規(guī)律,給出釋放高度的選擇建議。貫入海床過程中,魚雷錨將克服錨端壓力和側(cè)摩阻力在海床中運(yùn)動(dòng),文中將其貫入過程分為三個(gè)階段：浸入階段、穩(wěn)定貫入階段、停止階段,并通過探究土層單元壓力變化分析各個(gè)階段的錨速變化原因,發(fā)現(xiàn)了魚雷錨和土層發(fā)生分離導(dǎo)致停止階段速度變化復(fù)雜這一現(xiàn)象。初始貫入深度與海床土層的密度、黏聚力、內(nèi)摩擦角有關(guān),文中選取三種類型的粘土進(jìn)行模擬并比較貫入深度；錨端形狀參數(shù)會(huì)影響端部壓力的分布,從而影響貫入深度,流線型的錨端更容易貫入土層；魚雷錨自重增加會(huì)使其表面積增加,側(cè)摩阻力也會(huì)因此變大,所以魚雷錨重量應(yīng)適當(dāng)選取,并非一味求大；初始貫入速度的選取不僅要滿足貫入深度的要求,還應(yīng)兼顧考慮精確性。由于復(fù)雜的海洋環(huán)境,魚雷錨及其錨鏈在水中受到諸如海流、礁石撞擊等載荷后其運(yùn)動(dòng)方向會(huì)發(fā)生傾斜,偏離豎直運(yùn)動(dòng),此時(shí)魚雷錨的方向穩(wěn)定性至關(guān)重要。由于初始貫入角的存在,魚雷錨的貫入過程會(huì)大幅度偏離豎直線,影響貫入深度,文中對該問題也進(jìn)行了模擬分析。
[Abstract]:Nowadays, oil and gas exploration in many countries in the world is shifting from shallow sea to deep sea, and safe and stable mooring foundation is very important for large deepwater oil and gas exploration equipment. Torpedo anchor is a new type of deep-water mooring foundation with high bearing capacity. It has been applied to the mooring system of FPSO and other equipment. After practical engineering verification, it fully meets the mooring requirements of offshore facilities. In this paper, the two major processes of torpedo anchor installation are simulated and calculated. In this paper, the stress of torpedo anchor and its chain in the water is analyzed in detail, and the mathematical model is given and the numerical calculation is carried out. The relationship between the release height of torpedo anchor and the initial penetration velocity is obtained. At the same time, the numerical simulation of the process is carried out by using the Abaqus model. The results are compared with the results of the Matlab calculation, and the general law of the torpedo anchor motion in the water is obtained. In the process of penetration, the torpedo anchor will overcome the pressure at the end of the anchor and the side friction to move in the seabed. In this paper, the penetration process is divided into three stages: immersion stage, steady penetration stage, and stop stage. By analyzing the reasons for the variation of anchoring velocity in each stage, it is found that the separation of torpedo anchor and soil layer leads to the complex variation of the velocity in the stop stage, the initial penetration depth, the density and cohesion of the seabed soil layer, the initial penetration depth, the density of the seabed soil layer, the cohesion force, and so on. In this paper, three types of clay are selected to simulate and compare the penetration depth, the shape parameters of the anchor end will affect the distribution of the end pressure, thus the penetration depth will be affected, and the streamlined anchor end will be easier to penetrate into the soil. The increase of the weight of torpedo anchor will increase its surface area and the side friction, so the weight of torpedo anchor should be properly selected, not blindly; the selection of initial penetration velocity should not only meet the requirements of penetration depth, Due to the complexity of the marine environment, torpedo anchors and their anchor chains may tilt and deviate from vertical motion when subjected to loads such as currents and reef impacts in the water, At this point the directional stability of torpedo anchors is very important. Due to the existence of initial penetration angle the penetration process of torpedo anchors will deviate greatly from the vertical line and affect the penetration depth.
【學(xué)位授予單位】：大連理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：P751

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本文編號(hào)：1618771