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甲板上浪和冲击载荷的数值模拟

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Numerical Simulations for Green Water Running on Deck and Impact Loads1
Lin Zhaowei, Zhu Renchuan, Miao Guoping
School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University Shanghai, P.R.China (200030)
E-mail：gpmiao@https://www.wendangku.net/doc/466925375.html,
Abstract A technique of dynamic mesh is specially introduced in a 2-D numerical wave tank to simulate the green water incident on a fixed FPSO model in head waves and oscillating vessels in beam sea conditions, respectively. Numerical results agree well with the corresponding experimental ones. It indicates the present numerical scheme and method can be used to actually simulate the phenomenon of green water on deck, and to predict and analyze the impact forces on floating structures due to green water. It is of great significance to further guide the ship design and optimization, especially for ship bow and its strength design. The mechanism may also help seaman to impose operation restrictions to avoid severe green water incidents. Keywords: Green water， numerical wave tank， dynamic mesh.
1 Introduction
Green water is one of the strongly nonlinear ship-wave interaction problems, usually occurring in harsh sea environments when an incoming wave significantly exceeds the freeboard and water runs onto the deck. Damage of deck equipments and superstructures, and deck cargo shifting will probably be caused by the huge impact forces due to the severe green water incidents. Ship capsizing may even happen due to green water on deck for high speed vessels. For running ships, green water incidents may be avoided by taking some operation measures, such as reducing the advancing speed or altering the course. For the ocean structures, such as FPSO (Floating Production, Storage and Offloading Unit), moored in a specified sea area, however, no operation measure could be adopted to reduce the possible green water on deck, and risks resulted from green water will be even severer than other vessels. Recently, some cases of bow damage and superstructures destroy of FPSO caused by server green water incidents were reported (Mac Gregor, 1999). The green water problem is arousing more attentions for research. In the past, the research of green water problem was mainly relied on the experimental means. Some limited progresses were also achieved recently with the development of numerical techniques and methods. Traditionally, probability method, combined with hydrodynamic theory, was adopted to estimate and analyze the green water related problems. The method cannot predict the amount of water and the hydrodynamic load on decks when water runs onto deck but gives only the probability of deck wetness and the pressure distribution on the deck, based on the assumption that the pressure on the deck corresponds to the static water pressure of shipped water. Subsequently, some other theories and methods based on the potential theories were developed to tackle the problem to some extends. For example, the dam breaking theory and wave overtopping theory were used to simulate the deck flow (Buchner, 1995；Greco et al, 2000), the flooded water theory and shallow water wave theory were applied to simulate the water running on deck (Mizoguchi，1989; Huang，1995; Ogawa et al，1998). Mixed Euler-Lagrange method was also adopted for parametric research for green water incident (Buchner & Cozinijn，1997；Faltinsen et al，2002). The
1
Support by the Specialized Research Fund for the Doctoral Program of Higher Education (Grant No.20030248014)
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https://www.wendangku.net/doc/466925375.html, strongly nonlinear phenomena, such as water jet, wave breaking, flipping and wrapping, cannot be accurately simulated in detail by the method. With the improving of the capability of high performance computer, various numerical models such as MAC，VOF，LEVEL-SET，SPH，CIP were developed and introduced to solve the problems involving free surface (Hirtand Nichols, 1981；Osher.et.al, 1988；Gingold, Monaghan, 1977；Yabe et al, 2001). Generally, those methods can provide velocity and pressure distribution of the fluid field, capture free surface deforming after a great deal of calculation. Nielsen and Mayer (2004) carried out some numerical investigation on the green water problem by using VOF method. Good results were obtained for the case of fixed FPSO in head waves, but they did not get satisfactory results for green water on a moving vessel in incident waves. It is still a difficult task to acutely simulate the green water on deck and the impact force on the deck structures. In the present paper, a 2-D numerical wave tank is used to simulate the phenomenon of wave-ship interaction and green water on deck, in which, continuity equation and Navier-Stokes equation are regarded as governing equations for modeling the fluid filed, the source technique is adopted to realize the incident wave generation and the absorption for reflected and transmitted waves, and the VOF method is used to capture the free surface deformation. Numerical simulations execute for green water incident of a fixed FPSO model in head waves and oscillating vessels in beam sea conditions, respectively. Ship oscillating motions are calculated by the potential theory. A technique of dynamic mesh is specially introduced in the numerical simulation to realize the green water occurring for an oscillating ship. Numerical results agree well with the corresponding experimental ones. It indicates the present numerical scheme and method can be used to actually simulate the phenomenon of green water on deck, and to predict and analyze the impact forces on floating structures due to green water. It is of great significance to further guide the ship design and optimization, especially for ship bow and its strength design. The mechanism may also help seaman to impose operation restrictions to avoid severe green water incidents.
2. Governing equations and numerical wave tank
Numerical simulations for green water phenomenon are executed in a 2-D numerical wave tank with the functions of incident wave making and the effective reflected and transmitted wave adsorption, which is similar to a 2-D physical wave tank. As shown in Fig.2 and Fig. 9, the numerical wave tank is divided into four zones: the wave making zone, the absorption zones for reflected waves and transmitted wave and the working zone, EF denotes the still water surface to divide the air region (upper side) and the water region (lower side). Supposing a right-handed Cartesian coordinate system o-xy is defined with the origin on the undisturbed free surface and oy axis pointing vertically upward, the continuity equation and Navier-Stokes equations can be written as
?ρ ? ( ρ u ) ? ( ρ v) + + =0 ?t ?x ?y
? ? 2 u ? 2 u ? ?p ?( ρ u) ?( ρ u) ?( ρ u) +u +v = μ? 2 + 2 ?? + Sx ?t ?x ?y ?y ? ?x ? ?x
? ? v ? v ? ?p ?( ρ v) ? ( ρ v) ? ( ρ v) +u +v = μ? 2 + 2 ?? ? ρ g + Sy ?t ?x ?y ?y ? ?y ? ?x
2 2
(1) (2) (3)
where u and v denote the velocity components of the fluid particles in the x and y direction, ρ denotes the fluid density, μ the dynamic viscosity and g the gravitational acceleration. The additional momentum source terms Sx and Sy in the x and y direction are specially introduced to realize the incident wave generation and the absorption for reflected and transmitted waves (Milgram，1970; Gilbert，1978). -2-

https://www.wendangku.net/doc/466925375.html, The VOF method is adopted to capture the free surface deformation, the equations can be written as：
?aq ?t +
2
? (uaq ) ?x
q
+
? (vaq ) ?y
=0
， q = 1, 2
(4)
(5) where aq is the volume fraction, denoting the ratio of volume of the q-th phase fluid occupying in a cell. Here q=0 and 1 denote the air phase and the water phase, respectively.
∑a
q =1
=1
3. Green water of FPSO in head waves
A 2-D investigation of green water incidents on a space fixed FPSO vessel was performed by Greco (Greco, 2001) both experimentally and numerically. The experimental results are used for the further validation of the efficiency of the present method and computations. The FPSO model and wave tank dimensions are shown in Fig.1 and Fig.2, respectively. In the experiments of Greco (2001), the FPSO model is simplified as a rectangular structure with its length and height being 1.5m and 0.248m, respectively, and a small circle of radius of 0.08 m at the bow corner. As same as the physical wave tank for the experiments, the length of numerical wave tank in the present computation is also taken as 13.5m. The lengths of the wave-making zone, the reflected wave absorption zone, the working zone and the transmitted wave absorption zone are taken as 2m, 2m, 7.5m and 2m, respectively. The water depth for both the physical and numerical wave tank is 1.035m and FPSO model, with the draft of 0.198m and the freeboard of 0.05m, is set at the center of working zone.
WL1 WL2 WL3 0.075m MWL 0.15m 0.2275m r=0.08m PR1 0.062m
FPSO
Fig.1 FPSO model
3.1 Mesh generation
The mesh for the numerical model is generated basically on the following considerations. To avoid dissipation for wave propagation, the number of grids in the horizontal direction should keep large enough. In the present computation, the grid size ?x is kept about 1% of the incident wave length in the wave-making zone, the reflected wave absorption zone and the working zone. For the aim to have an effective wave adsorption, the size of the grid in the transmitted wave absorption zone increases gradually larger with a ratio of 1.2 from the rightmost boundary of the working zone. In the vertical direction,?y is taken about 5% of the wave height near the free surface region in order to reconstruct the free surface accurately, and increases larger gradually outside the region. Additionally, more refined grids are used near the bow of the FPSO to describe accurately the nonlinear phenomena due to the wave and body interaction.
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A Stillwaterlevel E Wave making zone Reflected wave absorption zone FPSO F L=1.5m Working zone H=1.035m D 2m m 2 7.5m 2m D=0.19 8 Transmitted wave absorption zone C
B
Fig.2 The numerical wave tank and its function zones
3.2 Wave making and absorption
Wave making and absorption are realized by using the technique of Wang and Liu (2005) in the present numerical simulation. Suppose the flow velocity and pressure in the fluid field after the wave making and absorption being:
(6) in which the subscripts C and I denote the values for the calculated physical variables and the incoming waves, λ=λ(x) is a smooth weighting function varying with the space position. The momentum source terms Sx and Sy may be deduced by substituting Eq. (6) to Eqs. (2) and (3), neglecting the viscosity terms and taking a linear difference discretization for the transient terms. The detailed deduction and expressions can be found in Wang and Liu (Wang and Liu, 2005) , In the present numerical scheme, the smooth weighting function is a sine function varying from 0 to 1, i.e.
?u M = λuC + (1 ? λ )u I ? ?vM = λvC + (1 ? λ )vI ? p = λp + (1 ? λ ) p C I ? M
λ ( x) = sin(
x ? x1 π ) x 2 ? x1 2 ，
(7)
in which x1 , x2 are the horizontal coordinates of the ends of the wave making or absorption zone. Suppose the horizontal coordinates being positive to the right direction in Fig.2, the velocities, pressure and the smooth weighting functions for different zones may be expressed as follows, i.e. In the wave making zone:
λ u M = λu I , v M = λv I , p M = λp I ,and λ xmin = 0， xmax = 1
In the reflected wave adsorption zone, the velocities can be expressed as Eq.(6) with
(8)
λ x =0
min
，
λx
=1
max
(9)
And in the transmitted wave adsorption zone: (10) It is easy to understand from the above discussions that the required waves in the fluid field can be generated with the corresponding flow velocities. In the case of the generation of the incident wave
u M = λuC , v M = λvC , p M = λpC ,and λ xmin = 1 λ xmax = 0
ζ = ζ a cos(kx ? ωt ) , its velocity components can be written as
?u = ζ aω cos(kx ? ωt ) ? ?v = ζ aω sin(kx ? ωt )
(11)
3.3 Solution of the problem
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https://www.wendangku.net/doc/466925375.html, As shown in Fig. 2, the rigid wall condition is imposed on the FPSO body surface and the left side AB, the right side CD and the bottom BD of the tank. On the upper side AC, the atmospheric pressure is used as a pressure boundary condition. At the initial stage, the tank is calm (i.e. u=0 and v=0) with an initial hydrostatic pressure distribution. Laminar flow assumption is adopted in the numerical simulation of the whole fluid domain. The first order implicit difference scheme is used for the discretization of the transient terms and the upper wind difference scheme for the discretization of the convection and diffusion terms in the momentum equations. SIMPLE scheme is adopted to solve the pressure and velocity iteratively. The present computational programs are interpreted and executes on the software platform of FLUENT by the way of User Define Function (UDF).
3.4 Numerical simulation and analysis
In the present computations, the wave length λ and wave height H are taken as 2m and 0.16m, respectively, and the advancing time step is 0.001 times of the wave period.
0.15
0.1
Elevation height (m)
0.05
0
-0.05
-0.1 12 14 16 18 20
Time(s)
Fig. 3 Time history of the wave profile at the location of 3m before the FPSO bow
Fig.3 shows the time history of the wave profile at the location of 3m before FPSO bow in the time interval from 12s to 20s. Although in that time interval the waves reflected by the bow already reach the wave making zone, a quite stable incident wave train can still generated from the wave making zone. It indicates that the present numerical scheme is effective for long time simulation due to the application of the reflected wave absorption technique. In the numerical simulation of green water occurrence, both the wave heights on deck and impact pressure on the deck structures are obtained. Figs.4-6 show the time histories of the wave height at the three probes WL1, WL2 and WL3, located respectively at the front end of the bow, 0.075m and 0.15 m from the bow end. The time histories of wave height at the three probes are also compared with the experimentally measured results shown as dotted curves in the figures. Well agreement between the numerical results and the experimental ones can be observed in the figures. At the early stage of green water occurrence when the first incident wave peak reaches the ship bow, the wave height in front of the bow is drove up due to the wave reflection. Thus wave height, when the next wave peak coming, becomes even higher in front of the bow, causing much severer green water on deck. As observed in Figs. 4-6, the wave height at the second time of green water is much larger than that at the first time. The results shown in Figs. 4-6 are obtained for the case of a space fixed FPSO without superstructures on the bow deck. In order to get insight into the mechanism of the impact of the green water flow acting on the ship bow structures, the case of a space fixed FPSO with a vertical structure mounted on the bow deck were also conducted. The structure is mounted on the fore part of the deck, 0.2275 m from the bow (refer to Fig. 1), and
-5-
0.15

https://www.wendangku.net/doc/466925375.html, is high enough to protect the wave overtopping from the top. The impact pressure at the location of 12 mm high from the deck on the structure, corresponding to the location of pressure gauge on the structure in the experiments, was calculated. The time histories of the impact pressure in one wave period from both the calculation and the experiment are depicted in Fig.7 with solid and dotted curves, respectively. Two significant peaks are observed in the figure. The first peak is the result of the initial impact, and the second appears when the water front begins to run down from the wall, after having reached its maximum height. Both the results are in good agreement. Since the flow on deck and the pressure on structures are very sensitive to and strongly affected by the initial fluid flow, as indicated by Greco (2001), no exactly the same results can be obtained from the repeating of experiments and computations.
-------Experiments Computations
0.15
Elevation height (m)
0.1
0.05
0 6.5 7 7.5 Time(s) 8 8.5 9
Fig.4 Time history of waves at probe WL1 located at the front end of the bow
0.15
------ Experiments Computations
Elevation height (m)
0.1
0.05
0 6.5 7 7.5 8 8.5 9
Time(s) Fig.5 Time history of waves at probe WL2 located at 0.075 from the bow end
0.15
Elevation height (m)
------Experiments Computations
0.1
0.05
0 6.5 7 7.5 8 8.5 9
Time(s) Fig.6 Time history of wave at probe WL3 located at 0.15 from the bow end
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https://www.wendangku.net/doc/466925375.html,
1.2
-------Experiments Computations
Pressure (k Pa)
0.8
0.4
0.0 -0.5
0.0
0.5
1.0
Time(s) Fig.7 Time history of impact pressure at probe PR1 on the mounted structure
4. Green water on ships oscillating in beam waves
Oscillating motions of floating bodies under the excitation of the incident waves will certainly give influence on the green water on deck and vice versa. Hence, it is necessary to count for the influence of floating body motions in the numerical simulations of green water. Numerical simulations for the case of an oscillating sectional ship model with shipping water running into its cabin were carried and the results were compared with the corresponding experimental results (Zhu and Saito, 2003).
B c l f D T
Fig. 8 Middle sectional model of Ship 499G/T without hatchcover
Fig.8 shows the middle sectional model of Ship 499G/T without hatchcover, the beam and depth of the model are 0.436m and 0.25m respectively. The hatch coaming height c is 0.032m, and the distance l between the sides of cabin and ship is 0.033m. The draught of the model is 0.19m. The physical experiments of water shipping into cabin were carried out in the 2-D tank of Hiroshima University with the water depth of 0.7m.
4.1 Numerical model of ship motion and dynamic mesh technique
To match the experimental conditions as much as possibly, the dimensions of each functional zones and the mesh size are slightly different from those mentioned in the former section. The definition of the boundary conditions and the method to generate the meshes in the zones for wave making, reflected wave and transmitted wave adsorption are primarily the same as we have done for the numerical simulation for green water on the FPSO. A technique of moving mesh is specially introduced in the numerical simulation to realize the green water occurring for an oscillating ship. -7-

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Ship section Wave making zone Reflected wave absorption zone
Working zone (Stationary grid zone)
(dynamic grid zone2)
1.6m
1.6m
11.6m
2.0 m
3.2 m
Fig.9 Tank model and zones for simulation of oscillating ship with green water occurring
Besides the considerations for the mesh generation in the former section, a reasonable dynamic mesh model is setup in the working zone to simulate the ship oscillation motions. As shown in Fig. 9, a rectangular dynamic mesh domain is defined and the others are kept as static mesh domains. In the dynamic mesh domain, a circular sub-region around the body is defined as a rigid mesh region, in which the meshes are fixed to the body, moving with the body in the oscillating modes of both translation and rotation. And in the remaining sub-region of the dynamic mesh domain, the meshes move only in translational modes. The boundaries between those two sub-regions are superposed. Refined meshes are used around the moving body and in the vicinity of the region boundary to avoid numerical errors to the most extent. The advantage of such a mesh scheme is that the computational precision and efficiency are been greatly improved since different modes of motion of the body can be effectively simulated by utilizing relative motion of the meshes, and meanwhile the complex deformations of meshes around the body are avoided.
4.2 Numerical simulation for green water occurrence on an oscillating ship
Table 1 Motion response of the ship sectional model (wave period T=1s)
Mode Sway Roll Heave
Motion ya/ζ za/ζ
Amplitude 0.47 0.42 0.90
Phase difference -79° 101° -90°
φa/kζ
In the numerical simulation for green water occurrence on an oscillating ship, the ship motions, including both the motion amplitudes and phase differences, are obtained in advance by the potential flow theory and the results are validated by experiments. Those results are used to generate the body motions in the numerical fluid field. Table 1 shows the motion responses of the sectional model of a hatch coverless ship excited by a regular wave train with period of 1 second. To save the computational time, the wave information is monitored at the position before the model to obtain the exact wave phase when the activated based on the phase difference between wave and the model motions. As shown in Fig. 10, similar phenomenon can be observed from the snap shots of green water on the oscillating model in waves for both numerical simulation and experiments.
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H=0.7m
(dynamic grid zone1)
Transmitted wave absorption zone

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(a) Visualization of computed free surface
(b) Visualization of experimental free surface
Fig. 10 Snap shots of green water on a ship oscillating in waves both in numerical simulation and experiments
◆
Experiments
600
——Computations
Volume (ml)
450 300 150 0 0.045
0.05
0.055
0.06
0.065
Wave steepness Fig.11 Comparison of shipped water volume for a ship oscillating in waves with the same period (T=1s) and various wave heights
The shipped water volume can be obtained by integrating the water phase in the cabin. A comparison of shipped water volume for both numerical computation and experiment is made for the ship oscillating in waves with the same period (T=1s) and various wave heights. From the results shown in Fig.11, by the present computational method, not only the process of the green water shipping onto deck can be effectively simulated but also a quite alike shipped water amount with the experiments can be obtained.
5. Conclusions
By specially introducing the technique of dynamic mesh, numerical simulations have been carried out successfully for the phenomenon of green water occurrence on a fixed FPSO model in head waves and an oscillating vessel in beam seas. Numerical results agree well with the corresponding experimental ones. It indicates the present numerical scheme and method can be used to actually simulate the phenomenon of green water on deck, and to predict and analyze the impact forces on floating structures due to green water. It is of great significance to further guide the ship design and optimization, especially for ship bow and its strength design. The mechanism may also help seaman to impose operation restrictions to avoid severe green water incidents. -9-

https://www.wendangku.net/doc/466925375.html, Present research mainly focuses on a 2-D dimensional problem of green water occurrence on oscillating vessel. The method can be extended to 3-D problems. And it also contributes for the further researches on strongly nonlinear problems of interaction of large amplitude wave and bodies.
Acknowledgement
The present research is jointly supported by the Excellent Young Teachers Program of MOE ， the Specialized Research Fund for the Doctoral Program of Higher Education (Grant No.20030248014) and the National Natural Science Foundation of China (NSFC) (Grant No. 50379026 and 50579034) All helps are greatly acknowledged by the authors.
Reference
Buchner B. (1995), “The impact of green water on FPSO design”, OTC’95, pp 76-98, Houston. Buchner B and Cozijin J L. (1997), “An investigation into the numerical simulation of green water”, Proc BOSS’97, Oxford,Vol 2 ,pp 113-125 Faltinsen O M, Greco M, Landrini M. (2002), “Green water loading on FPSO”, J of Offshore Mech and Artic Eng, Vol 124, pp 94-103 Fluent 6.0 UDF Manual, Fluent Inc. (2001-11-29) Gilbert G. (1978), “Absorbing Wave Generators”, Hydraulic Research Station Notes. Hydraulic Research Station, Wallingford, Oxford, UK, pp 3-4 Greco M, Faltinsen O M and Landrini M. (2000), “Basic studies of water on deck”, 23rd Symp on Naval Hydrodyn, France. Greco M, Faltinsen O M and Landrini M. (2001), “Green water loading on a deck structure”, Proc 16th Int workshop on Water Waves and Floating Bodies, Hirt, C.W., Nichols, B.D. (1981), “Volume of fluid (VOF) method for the dynamics of free boundaries”, https://www.wendangku.net/doc/466925375.html,put. Phys,Vol 39, pp 201–225. Huang Z L. (1995), “Nonlinear shallow water flow on deck and its effect on ship motion”, PhD thesis, Technical Univ of Nova Scotia, Halifax. Mac Gregor J R, Black, F, Wright D, (1999), “Design and construction of FPSO vessel for the Schiehallion field”, Trans RINA,.London, pp 270 - 304. Milgram J H. (1970), “Active Water-wave Absorbers”, J. Fluid Mechanics, Vol 43, No 4, pp 845-859 Monaghan J J. (1992), “Smoothed particle hydrodynamics”, Annu Rev Astron Astrophys., Vol 30, pp 543-574 Nielsen KB, Stefan M. (2004), “Numerical prediction of green water incidents”, Ocean Engineering, Vol 31, No (3 - 4), pp 363 - 399. Ochi M K. (1964), “Extreme behavior of a ship in rough seas-slamming and shipping of green water”, Annual meeting of SNAME, New York, pp 143-202 Ogawa, Y., Taguchi, H., Ishida, S. (1998), “A prediction method for the shipping water heights and its load on deck”, In: Practical Design of Ships and Mobile Units (PRADS), pp 535–543. Osher S and Sethian J A. (1988), “Fronts propagating with curvature-dependent speed: Algorithms based on Hamilton-Jacobi formulation”, J Comp Phys, Vol 79, No 1, pp 12-20 Wang B L，Liu H. (2005)，“Higher Order Boussinesq-Type Equations for Water Waves on Uneven Bottom”, Applied Mathematics and Mechanics，Vol 26, No 6, pp 714—722. Yabe T, Xiao F and Utsumi T. (2001), “The constrained interpolation profile method for multiphase analysis”, J Comp Phys, Vol 69,pp 556-593 Zhu R.C. and Saito K.(2003), “Study on the Shipping Water into an Open-Top Container”, Journal of Shanghai Jiaotong University, Vol 37, No 8, pp 1164 - 1171.
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海上自航甲板货船审图指南(2015修订)ccc

海上自航甲板货船审图指南（2015修订）一、适用范围 1.1适用于结构计算船长［以下简称船长(L)，如无特别说明均指此船长）］小于150米，舯0.5L范围内强力甲板上无开口(小型舱口盖、人孔盖除外)、货物装载于干舷甲板上的机动船(不包括采用吊车进行吊装的船载驳)。 1.2适用于在浙江省内建造、由本局及分支机构审查或符合性审查的船舶。二、审查依据的法规、规范：《国内航行海船法定检验技术规则》（2011）及其2012、2014年修改通报《国内航行海船建造规范》（2012）及其2013、2014年修改通报《钢质海船入级规范》（2012）《起重设备法定检验技术规则》（1999）《船舶与海上设施起重设备规范》（2007）。三、船体结构 3.1 结构布臵 3.1.1 船体结构的一般规定除下述条款给予明确规定外，按《国内航行海船建造规范》（2012）第2篇第2章进行结构设臵。本条款中的L L系指最深分舱载重线（相应于核定的夏季载重线）两端的垂线间量得的长度。 3.1.2水密横舱壁的总数一般应不少于表1的规定，水密横舱壁的布

臵应注意合理均匀。表1 水密横舱壁总数 3.1.3对于B/D≤６的自航甲板货船，一般应按表2的要求设臵首尾贯通的纵舱壁，其构件尺寸应按水密纵舱壁的要求计算，纵舱壁应注意合理布臵。表2 纵舱壁总数注: ①中纵舱壁可由纵向桁架代替，桁架校核按《国内航行海船建造规范》（2012）第2篇第12章驳船要求。 3.1.4对于B/D≥3的自航甲板货船，按照《国内航行海船建造规范》（2012）第2篇第12章附录“箱形驳船横向强度校核方法”，用直接计算校核其横向强度。 3.2 总纵强度船长大于等于65m的自航甲板货船应进行总纵强度校核，但不应进行有限航区的折减。 3.2.1 对于满足下列条件的船舶，按《国内航行海船建造规范》（2012）第2篇第2章第2节进行总纵强度校核。 L/B＞5 B/D＜2.5 Cb≥0.6 3.2.2 对于满足下列条件的船舶，且水密横舱壁和纵舱壁的设臵满足

甲板上浪和冲击载荷的数值模拟

船舶各部位名称

船的前端叫船首（stem）；后端叫船尾（stern）;船首两侧船壳板弯曲处叫首舷（bow）；船尾两侧船壳板弯曲处叫尾舷（quarter）；船两边叫船舷（ships side）；船舷与船底交接的弯曲部叫舭部（bilge）。连接船首和船尾的直线叫首尾线（fore and aft line center line,centre line）。首尾线把船体分为左右两半，从船尾向前看，在首尾线右边的叫右舷（starboard side）；在首尾线左边的叫左舷（port side）。与首尾线中点相垂直的方向叫正横（abeam），在左舷的叫左正横；在右舷的叫右正横。船体水平方向布置的钢板称为甲板，船体被甲板分为上下若干层。最上一层船首尾的统长甲板称上甲板（upper deck）。这层甲板如果所有开口都能封密并保证水密，则这层甲板又可称主甲板（main deck）,在丈量时又称为量吨甲板。少数远洋船舶在主甲板上还有一层贯通船首尾的上甲板，由于其开口不能保证水密，所以只能叫遮蔽甲板（shelter deck）。主甲板把船分为上下两部分，在主甲板以上的部分统称为上层建筑；主甲板以下部分叫主船体。在主甲板以下的各层统长甲板，从上到下依次叫二层甲板、三层甲板等等。在主甲板以上均为短段甲板，习惯上是按照该层甲板的舱室名称或用途来命名的。如驾驶台甲板（bridge deck）、救生艇甲板（life-boat deck）、等等。在主船体内，根据需要用横向舱壁分隔成很多大小不同的舱室，这些舱室都按照各自的用途或所在部位而命名，如图1-18所示，从首到尾分别叫首尖舱、锚链舱、货舱、机舱、尾尖舱和压载舱等。在货舱中两层甲板之间所形成的舱间称甲板间舱（tween deck），也叫二层舱或二层柜。上层建筑分船楼和甲板室两大类型。所谓船楼是指两侧都延伸至船舷或很接近船舷的上层建筑；甲板室是指两侧不接近舷边的上层建筑。船楼又有首楼（forecastle）、尾楼（poop）和驾驶台（bridge）之分。上层建筑的各舱室一般按舱室用途而命名。船体的基本结构船体由甲板、侧板、底板、龙骨、旁龙骨、龙筋、肋骨、船首柱、船尾柱等构件组成。实际船舶的船体结构是十分复杂的，而舰船模型的船体结构简单。舰船模型船体结构参照下图。龙骨龙骨是在船体的基底中央连接船首柱和船尾柱的一个纵向构件。它主要承受船体的纵向弯曲力矩，制作舰船模型时要选择木纹挺直、没有节子的长方形截面松木条制作。旁龙骨旁龙骨是在龙骨两侧的纵向构件。它承受部分纵向弯曲力矩，并且提高船体承受外力的强度。舰船的旁龙骨常用长方形截面松木条制作。肋骨肋骨是船体内的横向构件。它承受横向水压力，保持船体的几何形状。舰船模型的肋骨常用三合板制作。龙筋龙筋是船体两侧的纵向构件。它和肋骨一起形成网状结构，以便固定船侧板，并能增大船体的结构强度。舰船模型的龙筋通常也由长方形的松木条制作。船壳板船壳板包括船侧板和船底板。船体的几何形状是由船壳板的形状决定的。船体承受的纵向弯曲力、水压力、波浪冲击力等各种外力首先作用在船壳板上。舰船模型的船壳板可以用松木条、松木板拼接粘结而成。舭龙骨有些船体还装有舭龙骨，它是装在船侧和船底交界的一种纵向构件。它能减弱船舶在波浪中航行时的摇摆现象。舰船模型的舭龙骨可以用厚0.5～1毫米的铜片或铁片制作。船首柱和船尾柱船首柱和船尾柱分别安装在船体的首端和尾部，下面同龙骨连接，它们能增强船体承受波浪冲击力和水压力，还能承受纵向碰撞和螺旋桨工作时的震动。船舶构造船舶是海上运输的工具。船舶虽有大小之分，但其结构的主要部分大同小异。船舶主要由以下部分构成：（一）船壳（Shell）船壳即船的外壳，是将多块钢板铆钉或电焊结合而成的，包括龙骨翼板、弯曲外板及上舷外板三部分。（二）船架（Frame）

船舶主要部位名称

船舶主要部位名称船舶由主船体和上层建筑两部分组成一、主船体主船体，也可称为船舶主体。它通常是指上甲板（或强力甲板）以下的船体，是船体的主要组成部分。船舶主体是由甲板和外板组成一个水密的外壳，内部被甲板、纵横舱壁及其骨架分隔成许多的舱室。外板，是构成船体底部、舭部及舷侧外壳的板，俗称船壳板。甲板，是指在船深方向把船体内部空间分隔成层的纵向连续的大型板架。按照甲板在船深方向位置的高低不同，自上而下分别将甲板称为：上甲板、第二甲板、第三甲板?? 上甲板，是船体的最高一层全通（纵向自船首至船尾连续的）甲扳。第二、三??甲板，统称为下甲板。沿着船长方向不连续的一段甲板，称为平台甲板，简称为平台。在双层底上面的一层纵向连续甲板称为内底扳。舱壁，是将船体内部空间分隔成舱室的竖壁或斜壁，沿着船宽方向设置的竖壁，称为横舱壁；沿着船长方向布置的竖壁，称为纵舱壁。在船体最前面一道位于船首尖舱后端的水密横舱壁，称为防撞舱壁，又称船首尖舱舱壁。位于尾尖舱前端的水密横舱壁，称为船尾尖舱舱壁。二、上层建筑在上甲板上，由一舷伸至另一舷的或其侧壁板离舷侧板向内不大于船宽 B （通常以符号 B 表示船宽）4%的围蔽建筑物，称为上层建筑，包括船首楼、桥楼和尾楼。其他的围蔽建筑物称为甲板室。但是，通常不严格区分时，将上甲板以上的各种围蔽建筑物，统称为上层建筑。（一）船首楼

位于船首部的上层建筑，称为船首楼。船首楼的长度一般为船长L （通常以符号L表示船长）10%左右。超过25% L的船首楼，称长船首楼。船首楼一般只设一层；船首楼的作用是减小船首部上浪，改善船舶航行条件；首楼内的舱室可作为贮藏室等舱室。（二）桥楼位于船中部的上层建筑，称为桥楼。桥楼的长度大于15%L且不小于本身高度 6 倍的桥楼，称长桥楼。桥楼主要用来布置驾驶室和船员居住处所。（三）船尾楼位于船尾部的上层建筑，称为船尾楼。当船尾楼的长度超过25%L时，称为长尾楼。船尾楼的作用可减小船尾上浪，保护机舱，并可布置船员住舱及其他舱室。（四）甲板室对于大型船舶，由于甲板的面积大，布置船员房间等并不困难，在上甲板的中部或尾部可只设甲板室。因为在甲板室两侧外面的甲板是露天的，所以有利于甲板上的操作和便于前后行走。（五）上层建筑的甲板（ 1 ）罗经甲板又称顶甲板，是船舶最高一层露天甲板，位于驾驶台项部，其上设有桅桁及信号灯架、各种天线、探照灯和标准罗经等。（2）驾驶甲板，系设置驾驶台的一层甲板，位于船舶最高位置，操舵室、海图" F& ]#Y5 Q'U4 X ） m'C. V; x3W4 V!R6 U : j7 y3X+ Z2I/ d5@- u * I-K3 |' ~*L' k,?- h4c. f） I2c 7 N$ {%E6 tG6 O

船舶原理名词解释

1.舷弧：船舶的甲板边线自船中向首尾逐渐升高，称为“舷弧”。 2.梁拱：甲板中线比其左右舷的甲板边线高，其高度差称为梁拱。 3.舷弧和梁拱作用：有利于甲板上浪，上浪后使甲板积水自首尾向船中，且自甲板中线流向船尾。 4.型线图：表示船体几何形状的图。 5.型表面：钢船型表面为外板的内表面，水泥船和木质船的型表面为船壳的外表面。 6.型线图的三个基准面：中线面，中站面，基平面 7.中线面：将船体分为左右舷两个对称部分的纵向垂直平面。 8.中站面：在船长中点处垂直于中线面和基平面的横向平面。 9.基平面：过龙骨线和中站面的交点O，并平行于设计水线面的平面。 10.平行中体：在船中前后有一段横剖面形状和中横剖面相同的船体，称为平行中体 11.船型系数：表示船体水下部分面积和体积肥瘦程度的无因次系数，这些系数的大小对分析船型和船舶性能等有很大作用。 12主尺度：根据《钢制海船入籍规范》定义的船型尺度。它位于吨位证上 13.最大尺度：包括各种附体结构在内的，从一端点到另一端点的总尺度。 14.登记尺度：根据《1966年国际船舶吨位丈量公约》中定义的，是主管机关在登记和计算船舶总吨位，净吨时所用的尺度。位于吨位证书上 15.主要剖面：中纵剖面，中横剖面，设计水线面这三个大致反映出船体几何形状特征 11.船长：首尾垂线间长 12.附体：桨、舵、舭龙骨、轴支架。 13.型长：沿设计水线，由首柱前缘量至舵柱后缘的水平间距，无舵柱的量至舵杆中心线。 14.型宽：在船舶最宽处，由一舷的肋骨外缘至另一舷外缘之间的水平间距。 15.型吃水：在船长中点处，由平板龙骨上缘量至夏季满载水线的垂直距离。 16.型深：在船的中横剖面处，沿船舷自平板龙骨上缘至上层连续甲板横梁上缘的垂直距离。 17.吃水差：首尾吃水的差值。 18.船体系数：水线面Aw，船中剖面面积Am，水线面系数Cw，中