{ "metadata": { "name": "" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "APPENDIX A:Geomatric Properties of an Area" ] }, { "cell_type": "heading", "level": 3, "metadata": {}, "source": [ "Example A.1:Page no. 786" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#Given\n", "#From fig. A-4(a) The given dimensions are\n", "l1=8 #inch\n", "l2=3 #inch\n", "l3=10 #inch\n", "l4=5 #inch\n", "l5=11.5 #inch\n", "l6=2 #inch\n", "\n", "#calculation\n", "ymean1=((l4*l3*l6)+(l5*l2*l1))/((l3*l6)+(l2*l1))\n", "#From fig. A-4(b)\n", "l1_=-8 #inch\n", "l2_=3 #inch\n", "l3_=10 #inch\n", "l4_=-1.5 #\n", "l5_=2 #inch\n", "ymean2=((l4_*l2_*-l1_)+(l1_*l3_*l5_))/((l2_*-l1_)+(l3_*l5_))\n", "d=ymean1-ymean2 #Depth of beam\n", "#From fig. A-4(c)\n", "la=8 #inch\n", "lb=6.5 #inch\n", "lc=10 #inch\n", "ld=13 #\n", "le=5 #inch\n", "lf=3 #inch\n", "ymean3=((lb*ld*la)-2*(le*lc*lf))/((ld*la-2*(lc*lf)))\n", "print\"Location of centroid in fig (a)is\",ymean1,\"inch\" \n", "print\"Location of centroid in fig (b)is\",ymean2,\"inch\"\n", "print\"Location of centroid in fig (c)is\",ymean3,\"inch\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Location of centroid in fig (a)is 8.54545454545 inch\n", "Location of centroid in fig (b)is -4.45454545455 inch\n", "Location of centroid in fig (c)is 8.54545454545 inch\n" ] } ], "prompt_number": 7 }, { "cell_type": "heading", "level": 3, "metadata": {}, "source": [ "Example A.2:Page no 789" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#Given\n", "#Dimension in the fig.A-7 a\n", "#The given dimensions are\n", "l1=8 #inch\n", "l2=8.55 #inch\n", "l3=10 #inch\n", "l4=5 #inch\n", "l5=1.5 #inch\n", "l6=2 #inch\n", "l7=4.45 #inch\n", "\n", "#Calculation\n", "Ix1=(1/12.0*l6*l3**3)\n", "A1=l6*l3\n", "dy1=(l2-l4)\n", "Ix2=(1/12.0*l1*(l5+l5)**3)\n", "A2=l1*(l5+l5)\n", "dy2=(l7-l5)\n", "I1=(Ix1+A1*dy1**2)+(Ix2+A2*dy2**2)\n", "print I1\n", "\n", "#Dimension in the fig.A-7 b\n", "l1_= 13 #inch\n", "l2_= 3 #inch\n", "l3_=10 #inch\n", "l4_=5 #inch\n", "l5_= 2 #inch\n", "l6_= 6.5 #inch\n", "l7_=4.45 #inch\n", "l8_=8.55 #inch\n", "l9_=6.5 #inch\n", "\n", "Ix1_=(1/12.0*l1_*(l2_+l5+l2_)**3)\n", "A1_=l1_*(l2_+l5+l2_)\n", "dy1_=(l8_-l9_)\n", "Ix2_=(1/12.0*l2_*(l3_)**3)\n", "A2_=l2_*(l3_)\n", "dy2_=(l7_-l4_)\n", "I2=(Ix1+A1*dy1**2)+(Ix2+A2*dy2**2)\n", "\n", "#Result\n", "print\"Moment of inertia for fig a is\",round(I1,0),\"inch**4\"\n", "print\"Moment of inertia for fig a is\",round(I2,0),\"inch**4\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "645.576666667\n", "645.576666667\n", "Moment of inertia for fig a is 646.0 inch**4\n", "Moment of inertia for fig a is 646.0 inch**4\n" ] } ], "prompt_number": 17 }, { "cell_type": "heading", "level": 3, "metadata": {}, "source": [ "Example A.3 Page no: 790" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#Given\n", "#From fig A-8(a)\n", "#The given dimensions are\n", "l1=100 #mm\n", "l2=400 #mm\n", "l3=600 #mm\n", "dx=250 #mm\n", "dy=200 #mm\n", "\n", "#Calculation\n", "#Rectangle A:\n", "Ix1=(1/12.0*l1*(l2-l1)**3)\n", "Ady=(l1*(l2-l1)*dy**2)\n", "Ix=(Ix1+Ady)\n", "Iy1=(1/12.0*(l2-l1)*l1**3)\n", "Adx=(l1*(l2-l1)*dx**2)\n", "Iy=(Iy1+Adx)\n", "\n", "#Rectangle B:\n", "Ix_=(1/12.0*l3*l1**3)\n", "Iy_=(1/12.0*l1*l3**3)\n", "\n", "#Rectangle C\n", "Ix3=(1/12.0*l1*(l2-l1)**3)\n", "Ady_=(l1*(l2-l1)*200**2)\n", "Ix3_=(Ix3+Ady_)\n", "Iy3=(1/12.0*(l2-l1)*l1**3)\n", "Adx_=(l1*(l2-l1)*dx**2)\n", "Iy3_=(Iy3+Adx)\n", "\n", "#Total Moment of inertia\n", "Itx=(Ix+Ix_+Ix3_)\n", "Ity=(Iy+Iy_+Iy3_)\n", "\n", "#Result\n", "print\"Moment of inertia across x is \",Itx,\"mm**4\"\n", "print\"Moment of inertia across y is \",Ity,\"mm**4\"\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Moment of inertia across x is 2900000000.0 mm**4\n", "Moment of inertia across y is 5600000000.0 mm**4\n" ] } ], "prompt_number": 2 }, { "cell_type": "heading", "level": 3, "metadata": {}, "source": [ "Example A.4 :page no. 793" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#Given\n", "#From fig A-12 a\n", "#The given length of sides are\n", "l1=100 #mm\n", "l2=300 #mm\n", "dy=200 #mm\n", "dx=250 #mm\n", "\n", "#Calculation\n", "#Rectangle A\n", "Ixy1=0\n", "A1=l1*l2\n", "Ixy1=Ixy1+A1*(-dx)*dy\n", "\n", "#Rectangle B\n", "Ixy2=0\n", "A2=0\n", "Ixy2=Ixy2+A2*dx*dy\n", "\n", "#Rectangle D\n", "Ixy3=0\n", "A3=l1*l2\n", "Ixy3=Ixy3+A3*(dx)*(-dy)\n", "Ixy=Ixy1+Ixy2+Ixy3\n", "\n", "#Result\n", "print\"The moment of inertia is\",Ixy,\"mm**4\"\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The moment of inertia is -3000000000 mm**4\n" ] } ], "prompt_number": 3 }, { "cell_type": "heading", "level": 3, "metadata": {}, "source": [ "Example A.5 :page no. 796" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#Given\n", "#From fig A-15 and From Example A.3 and A.4\n", "Ix=2.9*10**9 #moment of inertia along x\n", "Iy=5.6*10**9 #moment of inertia along y\n", "Ixy=-3*10**9 #moment of inertia along xy\n", "\n", "#Calculation\n", "import math\n", "#Using eq. A11\n", "import math\n", "thetaP1=1/2.0*math.atan(-Ixy*2/(Ix-Iy))*100\n", "#As shown in fig. A-15\n", "thetaP2=-32.9 #degree\n", "Imax=(Ix+Iy)/2.0+math.sqrt((((Ix-Iy)/2.0)**2)+Ixy**2)\n", "Imin=(Ix+Iy)/2.0-math.sqrt((((Ix-Iy)/2.0)**2)+Ixy**2)\n", "\n", "#Result\n", "print\"Maximum moment of inertia is\",Imax,\"mm**4\"\n", "print\"Minimum moment of inertia is\",Imin,\"mm**4\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Maximum moment of inertia is 7539756829.92 mm**4\n", "Minimum moment of inertia is 960243170.081 mm**4\n" ] } ], "prompt_number": 22 }, { "cell_type": "heading", "level": 3, "metadata": {}, "source": [ "Example A.6 :page no. 799" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#given\n", "#From fig. A-17 a and Example A.3 and A.4\n", "Ix=2.9*10**9 #mm**4, moment of inertia\n", "Iy=5.6*10**9\n", "Ixy=-3*10**9\n", "\n", "#Calculation\n", "import math\n", "d=(Ix+Iy)/2.0 #distance of centre of circle \n", "#from fig A-17 b\n", "BC=1.35\n", "AB=3\n", "CA=math.sqrt(BC**2+AB**2)\n", "\n", "#the circle intersect the I axis at point (7.54,0) and (0.960,0) hence\n", "Imax=7.54*(10**9) #mm**4\n", "Imin=0.960*(10**9) #mm**4\n", "thetap1=1/2.0*(180-(math.atan(AB/BC))*180/math.pi)\n", "\n", "#Result\n", "print\"The maximum moment of inertia is\",Imax,\"mm**4\"\n", "print\"The minimum moment of inertia is\",Imin,\"mm**4\"\n", "print\"The angle is \",round(thetap1,1)\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The maximum moment of inertia is 7540000000.0 mm**4\n", "The minimum moment of inertia is 960000000.0 mm**4\n", "The angle is 57.1\n" ] } ], "prompt_number": 33 } ], "metadata": {} } ] }