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，
并得到以下各数值（对半剖面）： 参考轴以上 参考轴以下 面积，cm2 492 1052 静矩，cm2·m 803.4 1035 惯性矩，cm2·m2 1467 1240 该船于中拱状态受到最大弯曲力矩为25940kN·m, 试计算为使船底板在第二次计算时的折减系数不小于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
?cr?19.6(
100t2)， N/mm2, s为肋距， t为板厚）。 s3． 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 t1=3.5mm；船底、舷侧板厚度5 ，中内龙t0=4.0mm; 甲板纵桁 200 × 60×6
骨 250 × 5 ，中垂弯矩 M＝1250 kNm， 剪力V＝
80×6
1125kN。
1
12m 图1
图2
8m 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 Esteel is 2.1×105 MPa and that of the aluminiumEalu is 0.7×105 MPa.
10m 10 16 20 3m 8m 15m Figure 3
(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.
2