2280X2000X200防沖板強度計算書

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1. Calculation Conditions ( 計算條件)

Contact angle（接觸角度）: 10o   

Frame Size（防沖板尺寸  寬 x 長 x 厚） :  2000B  x 2380L x 200H

2. Calculation of Sectional Force (局部力的計算方式)

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，就在船只接觸護板同時彎曲矩 M 變成最大 （M最大）。因此在M最大 下的M最大 和 S最大 （最大局部力）應(yīng)按以下方式計算

2.1 Maximum Bend Moment ( M max)  最大彎曲矩 （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. （假設(shè)船只以10度角接觸護板，而護板可認作是一個橫梁， 橡膠部分認作是彈簧，鏈條部分的位置作為支點，則彎曲矩可如下計算）

        Picture 1.  Calculation Model for Bend Moment

        （圖1：彎曲矩的計算模型）

Max bend moment (M max) could be calculated by the following process because it generates just before a vessel contact the board.

因為只有當(dāng)船只接觸護板時才可產(chǎn)生最大彎曲矩 （M最大），所以它可以按下列程序計算

That is, Load F = 610kN （就是說橡膠的加載F = 754kN）

Accordingly, by putting L = (415+1050) = 1465mm  L1 = 415mm;  L2= 1050mm

據(jù)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

     （它產(chǎn)生于鏈條附件位置，該剪切力等同于作用于鏈條上的加載）

3. Stress Examination （應(yīng)力測定）

3.1 Cross-sectional form for M max is as follows: （M最大 的橫截面形式如下：）

At first, the cross-sectional second moment of this section and the cross-sectional coefficient Z are calculated.

（首先計算本部分的橫截面的第二力矩和橫截面系數(shù)Z）

Cross-sectional second moment I = 2.425 x 108

（橫截面的第二力矩）

Cross-sectional coefficient Z = 2.46 x 106

（橫截面系數(shù)Z）

      Thus, bending stress σ= M max/Z = 2.425 x 108/2.46 x 106

      （因此彎曲應(yīng)力） = 98.6N/mm2 < SS400 acceptable stressσa = 140N/mm2

      Therefore, it can be said enough safe. （因此可以說是足夠的安全）

                Picture 2. Cross-sectional form of the perpendicular direction

                 （圖2：垂直方向的橫截面形式）

   

3.2 Cross-sectional stressЧ for S max can be considered to be taken by wave and calculated as follows: （針對S最大橫截面應(yīng)力可認為從波狀運動中獲取并計算如下）

Cross-sectional stress Ч = S max/Aw

橫截面應(yīng)力

Aw: cross section area of wave ( = 10800mm2)

（Aw：波狀運動的橫截面區(qū)域

      Ч = 310 x 1000/10800

         = 28.7N·mm2 < SS 400 acceptable stressσa = 80N/mm2

   

  Therefore, it can be said enough safe.

  （因此可以說是足夠的安全）