{ "metadata": { "name": "", "signature": "sha256:b8ffe836d5b15b63c70d69d0a02ef23ccdf3f03c0f15c98f0fa5e62d24f5d894" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "Chapter 21: Wing spars and box beams" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 21.1 Pg.No.585" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from __future__ import division\n", "from scipy import integrate\n", "import math\n", "\n", "Mx=20*10**6 #internal bending moment (N.mm)\n", "Sy=-20*10**3 #force applied(N)\n", "l1=400\n", "l2=300 #lengths of webs respectively from left to right in Fig 21.2\n", "l3=200\n", "\n", "#Ixx=I_C+Ab^2\n", "Ixx=2*l1*150**2+2*l2**3/12\n", "y=150\n", "sigma_z1=Mx*y/Ixx\n", "sigma_z2=-Mx*y/Ixx\n", "\n", "Pz1=sigma_z1*l1\n", "Pz2=sigma_z2*l1\n", "\n", "#from fig 21.1 and 21.2\n", "del_y1_by_del_z=-0.05\n", "del_y2_by_del_z=0.05\n", "Syw=Sy-Pz1*del_y1_by_del_z-Pz2*del_y2_by_del_z\n", "\n", "# equ 21.6 qs=-Syw/Ixx*integrate(t_D*y*ds+B1*Y1) from 0 to s\n", "fn=lambda s:300-2*s\n", "\n", "def shear(s):\n", " return -Syw/Ixx*(integrate.quad(fn, 0, s)[0]+400*150)\n", "print \"maximum value of shear flow @s=150mm =%2.1f N/mm\\n\"%(shear(150.0))\n", "print \"value of shear @s=0mm = %2.1f N/mm\\n\"%(shear(0))\n", "print \"value of shear @s=300 mm = %2.1f N/mm\\n\"%(shear(300))\n", "\n", "\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "maximum value of shear flow @s=150mm =53.8 N/mm\n", "\n", "value of shear @s=0mm = 39.1 N/mm\n", "\n", "value of shear @s=300 mm = 39.1 N/mm\n", "\n" ] } ], "prompt_number": 8 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 21.2 Pg.No.589" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from __future__ import division\n", "from sympy import symbols\n", "import math\n", "\n", "Sy=100*10**6 #load applied in y direction (N)\n", "Sx=0 #load in x direction (N)\n", "y=[0.3,0.3,0.3,-0.3,-0.3,-0.3]\n", "B=[900,1200,900,900,1200,900] #boom area\n", "dx_dz=[0.1,0,-0.1,-0.1,0,0.1]\n", "dy_dz=[-0.05,-0.05,-0.05,0.05,0.05,0.05]\n", "Er=[0.6,0,0.6,0.6,0,0.6] \n", "nr=[0.3,0.3,0.3,0.3,0.3,0.3]\n", "Mx=-Sy*2\n", "My=-Sx*2\n", "Ixy=0\n", "Ixx=4*900*300**2+2*1200*300**2\n", "Pzr=[0]*6\n", "Pxr=[0]*6 #array initialization\n", "Pyr=[0]*6\n", "Pr=[0]*6\n", "print \"Boom \\t Pzr(kN) \\t dx_dz \\t dy_dz \\t Pxr(kN) \\t Pyr(kN) \\t Pr(kN)\"\n", "for i in range (0,6):\n", " Pzr[i]=Mx*y[i]/Ixx*B[i]\n", " Pxr[i]=Pzr[i]*dx_dz[i] #Pr is not correct in (7) column in book\n", " Pyr[i]=Pzr[i]*dy_dz[i]\n", " Pr[i]=(Pzr[i]**2+Pxr[i]**2+Pyr[i]**2)**0.5\n", " if Pzr[i]>0 :\n", " print \"%1.0f \\t %3.0f \\t\\t %1.1f \\t %1.2f \\t %2.0f \\t\\t %1.1f \\t\\t %3.1f\"%(i+1,Pzr[i],dx_dz[i],dy_dz[i],Pxr[i],Pyr[i],Pr[i])\n", " else:\n", " print \"%1.0f \\t %3.0f \\t\\t %1.1f \\t %1.2f \\t %2.0f \\t\\t %1.1f \\t\\t %3.1f\"%(i+1,Pzr[i],dx_dz[i],dy_dz[i],Pxr[i],Pyr[i],-Pr[i])\n", " \n", "Sxw=0\n", "Syw=66.6*10**3\n", "qb16=0 #open section here\n", "qb12=qb16-Syw/Ixx*B[0]*300\n", "qb23=qb12-Syw/Ixx*B[1]*300\n", "qb34=qb23-Syw/Ixx*B[2]*300\n", "qb45=qb23\n", "qb56=qb12\n", "qs0=-97\n", "\n", "\n", "print \"\\n\\nqb16 = %3.1f N/mm\"%(qb16)\n", "print \"qb12 = %3.1f N/mm\"%(qb12)\n", "print \"qb23 = %3.1f N/mm\"%(qb23)\n", "print \"qb34 = %3.1f N/mm\"%(qb34)\n", "print \"qb45 = %3.1f N/mm\"%(qb45)\n", "print \"qb56 = %3.1f N/mm\"%(qb56)\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Boom \t Pzr(kN) \t dx_dz \t dy_dz \t Pxr(kN) \t Pyr(kN) \t Pr(kN)\n", "1 \t -100 \t\t 0.1 \t -0.05 \t -10 \t\t 5.0 \t\t -100.6\n", "2 \t -133 \t\t 0.0 \t -0.05 \t -0 \t\t 6.7 \t\t -133.5\n", "3 \t -100 \t\t -0.1 \t -0.05 \t 10 \t\t 5.0 \t\t -100.6\n", "4 \t 100 \t\t -0.1 \t 0.05 \t -10 \t\t 5.0 \t\t 100.6\n", "5 \t 133 \t\t 0.0 \t 0.05 \t 0 \t\t 6.7 \t\t 133.5\n", "6 \t 100 \t\t 0.1 \t 0.05 \t 10 \t\t 5.0 \t\t 100.6\n", "\n", "\n", "qb16 = 0.0 N/mm\n", "qb12 = -33.3 N/mm\n", "qb23 = -77.7 N/mm\n", "qb34 = -111.0 N/mm\n", "qb45 = -77.7 N/mm\n", "qb56 = -33.3 N/mm\n" ] } ], "prompt_number": 6 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 21.3 Pg.No.593\n" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from __future__ import division\n", "from sympy import symbols\n", "import numpy as np\n", "import math\n", "yr=symbols('yr')\n", "\n", "Mx=-100*1.9*10**6 #bending moment(N.mm)\n", "Ixx=4*900*295**2+2*1200*295**2 #second moment of area (mm^4)\n", "sigma_zr=Mx/Ixx*yr\n", "P1_1=P3_1=-0.364*295*900\n", "P4_1=P6_1=0.364*295*900\n", "P2_1=-0.364*295*1200\n", "P5_1=0.364*295*1200\n", "\n", "Mx=-100*2.1\n", "Ixx=4*900*305**2+2*1200*305**2\n", "sigma_zr=Mx/Ixx*yr\n", "P1_2=P3_2=-0.376*305*900\n", "P4_2=P6_2=0.376*305*900\n", "P2_2=-0.376*305*1200\n", "P5_2=0.376*305*1200\n", "\n", "deltaP1=deltaP3=(P1_1-P1_2)/200\n", "deltaP4=deltaP6=-(P4_1-P4_2)/200\n", "deltaP2=(P2_1-P2_2)/200\n", "deltaP5=(P5_1-P5_2)/200\n", "\n", "a=np.array([[1,-1,0,0,0,0],[0,1,-1,0,0,0],[0,0,1,-1,0,0],[0,0,0,1,-1,0],[0,0,0,0,1,-1],[600*300*2,2*600*300,600*600,0,0,600*600]])\n", "\n", "b=np.array([43.8,32.85,-32.85,-43.8,-32.85,600*10**5])\n", "q=np.linalg.solve(a,b)\n", "print \"shear flow distribution :\"\n", "print \"q12 = %2.1f N/mm\"%(q[0])\n", "print \"q23 = %2.1f N/mm\"%(q[1])\n", "print \"q34 = %2.1f N/mm\"%(q[2])\n", "print \"q45 = %2.1f N/mm\"%(q[3])\n", "print \"q56 = %2.1f N/mm\"%(q[4])\n", "print \"q61 = %2.1f N/mm\\n\"%(q[5])" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "shear flow distribution :\n", "q12 = 63.6 N/mm\n", "q23 = 19.8 N/mm\n", "q34 = -13.1 N/mm\n", "q45 = 19.8 N/mm\n", "q56 = 63.6 N/mm\n", "q61 = 96.4 N/mm\n", "\n" ] } ], "prompt_number": 40 }, { "cell_type": "code", "collapsed": false, "input": [], "language": "python", "metadata": {}, "outputs": [], "prompt_number": 41 } ], "metadata": {} } ] }