1. Calculation Conditions ( 计算条件) Contact angle（接触角度）: 10o Frame Size（防冲板尺寸 宽 x 长 x 厚） : 2000B x 2380L x 200H
2. Calculation of Sectional Force (局部力的计算方式) Among sectional forces, Bend Moment M becomes maximum just before a vessel contact to the board (M max). Thus M max and S max ( maximum sectional force) under M max could be calculated shown below （在局部力之中，就在船只接触护板同时弯曲矩 M 变成最大 （M最大）。因此在M最大 下的M最大 和 S最大 （最大局部力）应按以下方式计算 2.1 Maximum Bend Moment ( M max) 最大弯曲矩 （M最大） Provided a vessel contacts a board at angle of 10 degrees horizontally, the board is considered to be a beam regarding a rubber parts as a spring and a chain attachment position as a fulcrum. Thus, bend moment could be calculated. （假设船只以10度角接触护板，而护板可认作是一个横梁， 橡胶部分认作是弹簧，链条部分的位置作为支点，则弯曲矩可如下计算）
Picture 1. Calculation Model for Bend Moment （图1：弯曲矩的计算模型）
Max bend moment (M max) could be calculated by the following process because it generates just before a vessel contact the board. 因为只有当船只接触护板时才可产生最大弯曲矩 （M最大），所以它可以按下列程序计算
That is, Load F = 610kN （就是说橡胶的加载F = 754kN） Accordingly, by putting L = (415+1050) = 1465mm L1 = 415mm; L2= 1050mm 据此， L = (415+1050) = 1465mm L1 = 415mm; L2= 1050mm
M max = 610 x 1000 x 1050x 415/1465= 1.776 x 108N·mm 2.2 Maximum Shearing Power ( S max) （最大剪切力）
It generates in a chain attachment position, and the power becomes equal to the load which acts on a chain exactly. That is, Smax = 305kN （它产生于链条附件位置，该剪切力等同于作用于链条上的加载）
3. Stress Examination （应力测定） 3.1 Cross-sectional form for M max is as follows: （M最大 的横截面形式如下：） At first, the cross-sectional second moment of this section and the cross-sectional coefficient Z are calculated. （首先计算本部分的横截面的第二力矩和横截面系数Z） Cross-sectional second moment I = 2.425 x 108 （横截面的第二力矩） Cross-sectional coefficient Z = 2.46 x 106 （横截面系数Z） Thus, bending stress σ= M max/Z = 2.425 x 108/2.46 x 106 （因此弯曲应力） = 98.6N/mm2 < SS400 acceptable stressσa = 140N/mm2 Therefore, it can be said enough safe. （因此可以说是足够的安全）
Picture 2. Cross-sectional form of the perpendicular direction （图2：垂直方向的横截面形式） 3.2 Cross-sectional stressЧ for S max can be considered to be taken by wave and calculated as follows: （针对S最大横截面应力可认为从波状运动中获取并计算如下）
Cross-sectional stress Ч = S max/Aw 横截面应力 Aw: cross section area of wave ( = 10800mm2) （Aw：波状运动的横截面区域 Ч = 310 x 1000/10800 = 28.7N·mm2 < SS 400 acceptable stressσa = 80N/mm2 Therefore, it can be said enough safe. （因此可以说是足够的安全）
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