傾覆船舶扳正過程中的受力分析與計算
發(fā)布時間：2018-08-19 20:42
【摘要】：船舶是水上載運的主體,在水上載運過程中有時會發(fā)生船舶傾覆事故。打撈傾覆船舶時,一般需要先對傾覆船舶進行扳正,使其達到甲板基本向上姿態(tài)。傳統(tǒng)制定傾覆船舶扳正方案時,一般根據以往經驗指導整個扳正過程,缺乏必要的設計理論與計算方法。針對上述問題,本文采用理論計算與軟件仿真模擬相結合的方法,研究了傾覆船舶扳正過程中的力學特性,推導了相關的計算公式,并討論了浮性、穩(wěn)性、擱坐力、泥土阻力、扳正速度以及水動力等因素對船舶扳正的影響。基于船舶靜力學原理,本文采用Euler角參數建立了傾覆船舶扳正力和力矩模型,提出了利用牛頓迭代法逐次逼近求解扳正力的方法;根據傾覆船舶扳正過程中縱傾角的變化量,推導了二/三維穩(wěn)性力矩的計算公式;通過分析破艙內進水、自由液面和氣穴的情況,提出了傾覆船舶破艙在扳正過程中的四種典型形式,并給出各種形式破艙在扳正過程中轉換的界限條件。當船舶擱淺于均質泥土時,本文通過在擱坐區(qū)域上建立多個平行于船舶縱軸和橫軸的矩形網絡,得到了船舶各處的入泥深度,進一步推導了擱坐力分布表達式并求解了泥土對船舶的阻力矩;當船舶擱淺于非均質泥土時,將泥土對船舶的作用分為船舶與海底之間的剪切阻力矩、海底泥土擁土阻力矩和泥土壓實阻力矩三種形式,利用M.H.Letoshnev提出的土體單位面積壓力和下陷量之間的關系推導了船舶擱坐力計算公式,得到船舶與海底之間的剪切阻力矩;采用Rankine被動土壓力理論計算擁土阻力矩,并根據船舶對泥土壓縮功得到了船舶壓實阻力矩的計算方法。水面傾覆船舶扳正過程模擬計算發(fā)現,扳正前期,合理調節(jié)自由液體數量和位置可以降低船體穩(wěn)性有利于扳正;扳正后期,自由液體的數量又是決定傾覆力矩大小的因素之一;而在扳正過程中,破艙傾覆船舶排水量會改變傾覆船舶的穩(wěn)性并隨著破艙進水量的改變而變化;單側艙室破損降低傾覆船舶穩(wěn)性,前期有利于扳正,后期卻會增加扳正的難度。擱淺傾覆船舶扳正過程模擬計算發(fā)現,擱淺傾覆船舶的初始穩(wěn)距和穩(wěn)性力矩均較小,而在扳正后期則會產生較大正/負向力矩,需要施加較大的扳正力矩以維持船舶平衡;深水擱淺船舶的初始穩(wěn)距較大,但其扳正后期需要的扳正力矩較小;當船體多點擱坐或擱坐在軟質灘涂時,設置過多的擱坐點不僅降低計算效率,也有增加計算錯誤幾率的風險,在滿足船體強度和工況的前提下,可以設置相對重要的擱坐點進行計算。根據剛體動力學理論,建立傾覆船舶扳正的運動方程;基于流體功能原理,推導了慣性類水動力及附加質量的計算方程;利用Taylor展開式得到粘性水動力公式;根據扳正過程中船舶運動的特點,得到粘性水動力的簡化算法;基于勢流理論推導了海水動壓力,進一步由Gauss公式得到規(guī)則波和不規(guī)則波波浪力計算公式;根據扳正過程中船舶受力特點,選用直接計算方式求解風力,采用Aage C推導的風作用力公式,進一步得到流力計算方法。
[Abstract]:The ship is the main body of the water transportation, and sometimes the ship overturning accident occurs in the course of the water transportation. When salvaging the overturned ship, it is usually necessary to correct the overturned ship first to make it reach the basic upward deck posture. In view of the above problems, this paper studies the mechanical characteristics of overturning ship in the course of rectification by combining theoretical calculation with software simulation, deduces relevant calculation formulas, and discusses the effects of buoyancy, stability, seating force, soil resistance, rectification speed and hydrodynamic forces on the ship's rectification. Based on the principle of ship statics, the Euler angle parameters are used to establish the model of the pulling force and moment of overturning ship, and the Newton iterative method is used to solve the pulling force successively. In the case of water, free surface and cavitation, four typical forms of overturning ship's damaged cabin in the course of correcting are proposed, and the boundary conditions for the conversion of various forms of damaged cabin in the course of correcting are given. When the ship is grounded in heterogeneous soil, the action of the soil on the ship is divided into three forms: the shear resistance moment between the ship and the seabed, the resistance moment of the seabed soil and the resistance moment of the soil compaction. The relationship between the pressure per unit area of the soil and the subsidence put forward by toshnev has deduced the formula for calculating the ship's grounding force and obtained the shear resistance moment between the ship and the seabed. The resistance moment of the ship's compaction is calculated by Rankine's passive earth pressure theory, and the calculation method of the resistance moment of the ship's compaction is obtained according to the ship's compression work to the soil. The simulation calculation of ship alignment shows that the amount and position of free liquids can reduce the stability of ship hull in the early phase of alignment, and the amount of free liquids is one of the factors that determine the magnitude of overturning moment in the later phase of alignment. The results show that the initial stable distance and moment of stability of the ship are small, but the positive / negative moment is large in the latter stage, which is needed. Applying larger pulling moment to maintain the balance of the ship; the initial stable distance of the ship grounded in deep water is larger, but the pulling moment needed in the later period is smaller; when the hull is on multi-point or on soft beach, setting too many berthing points not only reduces the calculation efficiency, but also increases the risk of calculation error, in order to meet the hull strength and to meet the requirements of the ship. Based on the rigid body dynamics theory, the motion equation of overturning ship is established; the calculation equations of inertia hydrodynamic force and additional mass are deduced based on the fluid function principle; the viscous hydrodynamic formula is obtained by Taylor expansion; and the ship transportation in the process of alignment is obtained. The simplified algorithm of viscous hydrodynamics is obtained based on the dynamic characteristics of the ship; the dynamic pressure of the sea water is deduced based on the potential flow theory, and the formulas for calculating the wave forces of regular and irregular waves are derived from the Gauss formula; according to the force characteristics of the ship in the course of rectification, the direct calculation method is selected to solve the wind force, and the wind force formula deduced from Aage C is used to further obtain the wind force formula. To the flow force calculation method.
【學位授予單位】：大連海事大學
【學位級別】：博士
【學位授予年份】：2017
【分類號】：U676.6
本文編號：2192777
[Abstract]:The ship is the main body of the water transportation, and sometimes the ship overturning accident occurs in the course of the water transportation. When salvaging the overturned ship, it is usually necessary to correct the overturned ship first to make it reach the basic upward deck posture. In view of the above problems, this paper studies the mechanical characteristics of overturning ship in the course of rectification by combining theoretical calculation with software simulation, deduces relevant calculation formulas, and discusses the effects of buoyancy, stability, seating force, soil resistance, rectification speed and hydrodynamic forces on the ship's rectification. Based on the principle of ship statics, the Euler angle parameters are used to establish the model of the pulling force and moment of overturning ship, and the Newton iterative method is used to solve the pulling force successively. In the case of water, free surface and cavitation, four typical forms of overturning ship's damaged cabin in the course of correcting are proposed, and the boundary conditions for the conversion of various forms of damaged cabin in the course of correcting are given. When the ship is grounded in heterogeneous soil, the action of the soil on the ship is divided into three forms: the shear resistance moment between the ship and the seabed, the resistance moment of the seabed soil and the resistance moment of the soil compaction. The relationship between the pressure per unit area of the soil and the subsidence put forward by toshnev has deduced the formula for calculating the ship's grounding force and obtained the shear resistance moment between the ship and the seabed. The resistance moment of the ship's compaction is calculated by Rankine's passive earth pressure theory, and the calculation method of the resistance moment of the ship's compaction is obtained according to the ship's compression work to the soil. The simulation calculation of ship alignment shows that the amount and position of free liquids can reduce the stability of ship hull in the early phase of alignment, and the amount of free liquids is one of the factors that determine the magnitude of overturning moment in the later phase of alignment. The results show that the initial stable distance and moment of stability of the ship are small, but the positive / negative moment is large in the latter stage, which is needed. Applying larger pulling moment to maintain the balance of the ship; the initial stable distance of the ship grounded in deep water is larger, but the pulling moment needed in the later period is smaller; when the hull is on multi-point or on soft beach, setting too many berthing points not only reduces the calculation efficiency, but also increases the risk of calculation error, in order to meet the hull strength and to meet the requirements of the ship. Based on the rigid body dynamics theory, the motion equation of overturning ship is established; the calculation equations of inertia hydrodynamic force and additional mass are deduced based on the fluid function principle; the viscous hydrodynamic formula is obtained by Taylor expansion; and the ship transportation in the process of alignment is obtained. The simplified algorithm of viscous hydrodynamics is obtained based on the dynamic characteristics of the ship; the dynamic pressure of the sea water is deduced based on the potential flow theory, and the formulas for calculating the wave forces of regular and irregular waves are derived from the Gauss formula; according to the force characteristics of the ship in the course of rectification, the direct calculation method is selected to solve the wind force, and the wind force formula deduced from Aage C is used to further obtain the wind force formula. To the flow force calculation method.
【學位授予單位】：大連海事大學
【學位級別】：博士
【學位授予年份】：2017
【分類號】：U676.6
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