10Lesson Ten(ok)

Lesson Ten Lesson Ten The Function of Ship Structural Components The strength deck, bottom, and side shell of a ship act as a box girder in resisting bending and other loads imposed on the structure. The main deck, bottom, and side shell also form a tight envelope to withstand the sea locally. The remaining structure contributes either directly to these functions or indirectly by maintaining the main members in position so that they can act efficiently. The bottom plating is a principal longitudinal member providing the lower flange of hull girder. It is also part of the watertight envelope, and subject to the local water head. At the forward end, it must withstand the dynamic pressure associated with slamming and plating thickness is usually increased to provide the necessary strength. When fitted, the inner bottom also makes a significant contribution to the strength of lower flange. It usually forms a tank boundary for the double bottom tanks and is subject to the local pressure of the liquid contained therein. In addition, it must support the loads from above, usually from cargo placed in the holds. The strength deck forms the principal member of the upper flange, usually provides the upper water tight boundary, and is subject locally to water, cargo, and equipment loadings. The remaining continuous decks, depending on their distance from the neutral axis, contribute to a greater or lesser extent in resisting the longitudinal bending loads. Certain decks which are not continuous fore and aft and not contribute to the longitudinal strength. Locally internal decks are subject to the loads of cargo, equipment, stores, living spaces, and, where they form a tank boundary or barrier against progressive flooding, liquid pressure. The side shell provides the webs for the main hull girder and is an important part of the watertight envelope. It is subject to static water pressure as well as the dynamic effects of pitching, rolling, and wave action. Particularly forward, the plating must be able to withstand the impact of the seas. Aft, extra plate thickness is beneficial in way of rudders, shaft structure and propellers for strength, panel stiffness, and reduction of vibration. Additional thickness is necessary at the waterline for navigation in ice. Bulkheads are one of the major components of internal structure. Their function in the hull girder depends on their orientation and extent. Main transverse bulkheads act as internal stiffening diaphragms for the girder and resist racking loads, but do not contribute directly to longitudinal strength. Longitudinal bulkheads, on the other hand, if extending more than about one-tenth the length of the ship, do contribute to longitudinal strength and in some ships are nearly as effective as the side shell itself. Bulkheads generally serve structural functions such as forming tank boundaries, supporting decks and load-producing equipment such as kingposts, and adding rigidity to produce vibration. In addition, transverse bulkheads provide subdivision to prevent progressive flooding. All applicable loads must be considered during design. The foregoing structural elements of a ship are basically large sheets of plate whose thicknesses are very small compared with their other dimensions, and which, in general, carry loads both in and normal to their plane. These sheets of plate may be flat or curved, but in either case they must be stiffened in order to perform their required function efficiently. The various stiffing members have several functions: (a) the beams support the deck plating; (b) the girder, in turn, support the beams, transferring the load to the stanchions or bulkheads; (c) the transverse frames support the side shell and the ends of the transverse deck beams and are, in turn, supported by decks and stringers; (d) the stiffeners support the bulkhead plating, and so on. As discussed in detail in section 4, the stiffening members are generally rolled, extruded, flanged, flat, or built-up plate sections with one edge attached to the plate they reinforced. Vertical plates often connect the bottom shell and inner bottom, stiffening both members. If oriented transversely, these plates are called floors, and if longitudinally oriented, center vertical keel or side girder, as appropriate. Stiffening members do not, of course, act independently of the plating to which they are attached. A portion of the plate serves as one flange of the stiffener, and properties such as section modulus and moment of the stiffener must reflect this. The American Bureau of Shipping (ABS) considers a width of plating equal to the stiffener spacing as effective, while Lloyd’s Register of Shipping (LR) assumes 24 in. to be effective. Stiffening members serve two functions, depending on how they are loaded. In the cases of loads normal to the plate, such as water loading on a transverse bulkhead, the stiffeners assume the load transferred from the plate. In the case of in-plane loads, such as those included in the deck by longitudinal bending of the hull girder, the beams serve to maintain the deck plating in its designed shape. If the deck beams are longitudinally oriented, they will, of course, carry the same primary stress as the plating and may contribute substantially to the hull girder strength. Pillars are used to support deck girders, longitudinal or transverse. These supports, in addition to carrying local loads from cargo, etc, serve to keep the deck and bottom from moving toward each other as a result of longitudinal bending of the hull girder. (From “Ship Design and Construction” by D’Arcangelo, 1969) Technical Terms 1.​  2.​ structural components 结构构件 3.​ strength deck 强力甲板 4.​ box girder 箱形梁 5.​ tight envelope 密闭外壳 5.​ longitudinal member 纵向构件 6.​ hull girder 船体梁 7.​ lower/upper flange 下/上翼缘板 8.​ forward/aft end 首/尾端 9.​ dynamic pressure 动压力 10.​ slamming 砰击 11.​ inner bottom 内底 12.​ hold 货舱 13.​ double bottom 双层底 14.​ hold 货舱 15.​ neutral axis 中和轴 16.​ longitudinal bending 纵向弯曲 17.​ longitudinal strength 总纵（纵向）强度 18.​ barrier 挡板，屏障 19.​ web 腹板 20.​ static water pressure 静水压力 21.​ impact 冲击 22.​ shaft strut 尾轴架 23.​ panel stiffness 板格刚性 24.​ vibration 振动 25.​ bulkhead舱壁 26.​ diaphragm 隔壁 27.​ racking load 横扭载荷 28.​ kingpost 起重柱 29.​ rigidity 刚度 30.​ subdivision 分舱 31.​ sheet 薄板 32.​ stanchion 支柱 33.​ stringer 船侧纵桁 34.​ roll 辗轧 35.​ extrude 挤压 36.​ flange 拆边，法兰 37.​ built-up plate sections 组合型材 38.​ bottom shell 外底板 39.​ floor 肋板 40.​ center vertical keel 中内龙骨，中桁材 41.​ side girder 旁桁材，旁纵桁 42.​ stiffener 扶强材 43.​ section modulus 剖面模数 44.​ moment of inertia 惯性矩 45.​ The American Bureau of Shipping (ABS) 美国验船局 46.​ spacing 间距 47.​ Lloyd’s Register of Shipping 劳氏船级社 48.​ in-plane 面内 49.​ beam 横梁 50.​ primary stress 第一类应力 51.​ pillar 支柱 52.​ deck girder 甲板纵桁 53.​ support 支柱（构件） Additional Terms and Expressions 1.​  2.​ main hull 主船体 3.​ superstructure 上层建筑 4.​ deckhouse 甲板室 5.​ bridge 桥楼 6.​ forecastle 首楼 7.​ poop 尾楼 8.​ stem 首柱 9.​ sternpost 尾柱 10.​ rudder post 舵柱 11.​ shaft bossing 轴包架 12.​ framing 骨架 13.​ longitudinal framing 纵骨架式 14.​ transverse framing 横骨架式 15.​ flat plate keel 平板龙骨 16.​ margin plate 内底边板 17.​ bilge bracket 舭肘板 18.​ side plate 舷（船）侧板 19.​ sheer strake 舷顶列板 20.​ stringer plate 甲板边板 21.​ shell expansion plan 外板展开图 22.​ bulwark 舷墙 23.​ hatch coaming 舱口围板 24.​ cantilever 悬臂梁 25.​ intercostal member 间断构件 26.​ cant frame 斜肋骨 27.​ pant beam 强胸横梁 28.​ lightening hole 减轻孔 29.​ bracket 肘板 30.​ bracket 肘板 31.​ hawse pipe 锚链筒 32.​ bulb plate 球扁钢 33.​ angle section 角钢 34.​ T section T型材 35.​ face plate 面板 36.​ butt 对接（缝） 37.​ seam 边接（缝） Notes to the Text 1.​ The remaining structure contributes either directly to these functions or indirectly by maintaining the main members in position so that they can act efficiently. 句中含有either directly---or indirectly---两个并列成分，而在indirectly 后省略了to these functions. by maintaining the main members in position so that---是用来修饰后者的；其中so that they can act efficiently 为目的状语从句。 2.​ be subject to (n.) 受------支配（易受，须经） be subjected to (n.) 受到，经受 Ships subject to the code should survive the normal effects of flooding following assumed hull damage caused by some external force. 受本规则约束的船舶应能承受在外力作用下船体遭受假定破碎后正常进水的影响。 All full penetration butt welds of the shell plating of cargo tanks should be subjected to 100 per cent radiographic inspection. 液货舱壳板所有全焊透对接焊缝应进行100%的射线照相检验。 课文中的be subject to 均可作为be subjected to 理解，翻译成“承受”，“经受”。 3.​ to a greater or lesser extent 在较大或较小程度上 4.​ Locally, internal decks are subject to the loads of cargo, equipment, stores, living spaces, and, where they form a tank boundary or barrier against progressive flooding, liquid pressure. 句中的where they form---flooding 为地点状语从句，然而带有条件性质，可理解为承受liquid pressure 的条件。 5.​ As discussed in detail in Section 4, the stiffening members are generally rolled, extruded, flanged, flat or built-up plate sections with one edge attached to the plate they reinforce. 句中的rolled, extruded, flanged, flat or built-up plate 都修饰sections. with one edge attached to the plate 是 with 后带主谓关系的复合短语。they reinforce 为省略关联词（从语中作宾语）的定语从句，修饰前面的the plate. 6.​ If oriented transversely, these plates are called floor, and if longitudinally oriented, center vertical keel or side girder, as appropriate. 两个if从句中省略主语及to be， 参见第九课注3. 在 center vertical keel or side girder 前面省略了these plates are called. As appropriate 可理解为as is appropriate 简化形式，关系代词as代替整个主句，并在从句中作主语，as appropriate, to passenger ships carrying dangerous goods. 如第54条规则的要求适合于载运危险货物的客船，应照此办理。 7.​ The American Bureau of Shipping (ABS) considers a width of plating equal to the stiffener spacing as effective, while Lloyd’s Register of Shipping (LR) assumes 24 in. to be effective. While 引出并列分句， 表 关于同志近三年现实表现材料材料类招标技术评分表图表与交易pdf视力表打印pdf用图表说话 pdf 示同时存在两种事物的对比。前句的considers… as effective 与后句的assumes… to be effective 结构相似，其中的as effective 和 to be effective 均作宾语补足语。