船舶结构强度作业

作 业

1． 长方形浮码头，长25m, 宽5m, 深3m, 空载时吃水1m （淡水）。当中部10m 范围内承受均布载

荷时，吃水增加到2m 。假定船体质量沿船长均匀分布，试作出该载荷条件下的浮力曲线、载荷曲线、静水剪力和弯矩曲线，并求出最大剪力和最大弯矩值。

2． 某型深为3.5m 的横骨架式船舶，第一次近似计算船中剖面要素时，参考轴选在基线上 1.4m 处，

不小于0.5, 该船底板的最小厚度至少应为多少（肋距为600mm, 船底板的临界应力

2

)100(

6.19s

t cr =σ， N/mm 2, s 为肋距， t 为板厚）。

3． 某方形驳船L=90m, 空船质量W=450t, 沿

全船均布，载矿砂500t 分布于船中部70m 。设矿砂沿船长均布，但沿船宽方向呈图1所示分布且前后反对称，试画出扭矩曲线。

4． 试计算图2所示横骨架式内河驳船在甲板和船底处的总纵

弯曲应力及中和轴处的剪应力（不计初挠度和横荷重的影响，不考虑板的折减）。已知：

型深 D ＝3.2m ， 船宽B ＝6.0m ， 吃水 d=2.0m ，

肋距 S ＝500mm; 甲板厚度 t 1=3.5mm ；船底、舷侧板厚度t 0=4.0mm; 甲

板纵桁

，中内龙骨

，中垂弯矩 M ＝1250 kNm ， 剪力V ＝

1125kN 。

图1

200×5 60×6

250×5 80×6

图2

5.

A ship with length 90 m, floats in still fresh water at a draft of 5.8 m when loaded. The weight curve of the loaded ship may be regarded as linear, from zero at the two ends to a maximum at the mid-length. The simplified cross-section of the hull with a superstructure is shown in Figure 3. The cross-sectional dimensions are also shown in Figure 2. The hull girder is made of steel and the superstructure of aluminium. The modulus of elasticity of the steel steel E is 2.1×105 MPa and that of the aluminium alu E is 0.7×105 MPa.

(a) Draw the shear force and bending moment curves respectively.

(b) Compute the normal stresses at top deck house and at the bottom shell of the mid-section respectively.

6． Analyze strength computational model of a typical deck grillage, ones of stability and

strength analyses of a longitudinal at deck, and one of a longitudinal at bottom for its strength analysis. Briefly explain the reasons.

Figure 3