{ "metadata": { "name": "", "signature": "sha256:a09e16c002c633d5d63dac7b4f943159d57261807392bec341e8052ebf397939" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "Chapter 8 : Concept of Stress" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 8.1 Page No : 158" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\t\t\t\n", "# Variables\n", "F = -100 \t\t\t#lb\n", "x1 = 3 \t\t\t#in\n", "y = 6 \t\t\t#in\n", "x2 = 24 \t\t\t#in\n", "x3 = 12 \t\t\t#in\n", "\t\t\t\n", "# Calculations\n", "Force = -F\n", "Moment = -F*(x2+x1)\n", "Torque = -F*y\n", "\t\t\t\n", "# Results\n", "print 'Force = %.2f lb'%(Force)\n", "print 'Moment =%.2f lb.in'%(Moment)\n", "print 'Torque =%.2f lb.in'%(Torque)\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Force = 100.00 lb\n", "Moment =2700.00 lb.in\n", "Torque =600.00 lb.in\n" ] } ], "prompt_number": 1 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 8.2 Page No : 159" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\t\t\t\n", "# Variables\n", "F = -5000. \t\t\t#lb\n", "D = 250. \t\t\t#lb/ft\n", "y1 = 4. \t\t\t#in\n", "y2 = 2. \t\t\t#in\n", "y3 = 5. \t\t\t#in\n", "y4 = 3. \t\t\t#in\n", "x = 3. \t\t\t#in\n", "\t\t\t\n", "# Calculations\n", "Ax = -D*y1\n", "Ay = -F\n", "M = (D*y1*(y2+y3+y1/2.))-F*x\n", "\t\t\t\n", "# Results\n", "print 'Ax = %.2f lb'%(Ax)\n", "print 'Ay =%.2f lb'%(Ay)\n", "print 'M =%.2f lb.in'%(M)\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Ax = -1000.00 lb\n", "Ay =5000.00 lb\n", "M =24000.00 lb.in\n" ] } ], "prompt_number": 2 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 8.3 Page No : 160" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math \n", "\t\t\t\n", "# Variables\n", "P = 5 \t\t\t#kips\n", "angle = 30 \t\t\t#degrees\n", "\t\t\t\n", "# Calculations\n", "Fn = P*math.sin(math.radians(angle))\n", "Ft = P*math.cos(math.radians(angle))\n", "\t\t\t\n", "# Results\n", "print 'Fn = %.2f lb'%(Fn)\n", "print 'Ft =%.2f lb'%(Ft)\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Fn = 2.50 lb\n", "Ft =4.33 lb\n" ] } ], "prompt_number": 1 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 8.4 Page No : 162" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math \n", "\t\t\t\n", "# Variables\n", "p = 5. \t\t\t#tons\n", "dt = 0.75 \t\t\t#in\n", "db = 0.5 \t\t\t#in\n", "b = 0.5 \t\t\t#in\n", "h = 2. \t\t\t#in\n", "\t\t\t\n", "# Calculations\n", "Sc = p*2000/((math.pi/4)*(dt**2))\n", "Sr = p*2000/(b*h)\n", "Sb = p*2000/(2*(math.pi/4)*db**2)\n", "\t\t\t\n", "# Results\n", "print 'Stress in circular scetion = %.2f psi tension'%(round(Sc,-2))\n", "print 'Stress in rectangular section = %.2f psi tension'%(Sr)\n", "print 'Stress in bolt = %.2f psi tension'%(round(Sb,-2))\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Stress in circular scetion = 22600.00 psi tension\n", "Stress in rectangular section = 10000.00 psi tension\n", "Stress in bolt = 25500.00 psi tension\n" ] } ], "prompt_number": 3 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 8.5 Page No : 168" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\t\t\t\n", "# Variables\n", "w = 8 \t\t\t#in\n", "wperft = 35. \t\t\t#lb/ft\n", "A = 10.3 \t\t\t#sq in\n", "F1 = 3. \t\t\t#tons\n", "F2 = 3. \t\t\t#tons\n", "F3 = -8. \t\t\t#tons\n", "F4 = -8. \t\t\t#tons\n", "F5 = -5. \t\t\t#tons\n", "F6 = -5. \t\t\t#tons\n", "Pl = 12. \t\t\t#in\n", "Pb = 12. \t\t\t#in\n", "\t\t\t\n", "# Calculations\n", "Sa = (F1+F2)*2000/A\n", "Sb = -(F3+F4+F1+F2)*2000/A\n", "Sc = -(F3+F4+F1+F2+F5+F6)*2000/A\n", "Sp = -(F3+F4+F1+F2+F5+F6)*2000/(Pl*Pb)\n", "\t\t\t\n", "# Results\n", "print 'Stress in a = %.2f psi tension'%(round(Sa,-1))\n", "print 'Stress in b = %.2f psi tension'%(round(Sb,-1))\n", "print 'Stress in c = %.2f psi tension'%(round(Sc,-1))\n", "print 'Stress in plate = %.f psi tension'%(Sp)\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Stress in a = 1170.00 psi tension\n", "Stress in b = 1940.00 psi tension\n", "Stress in c = 3880.00 psi tension\n", "Stress in plate = 278 psi tension\n" ] } ], "prompt_number": 7 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 8.6 Page No : 166" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math \n", "\t\t\t\n", "# Variables\n", "Ns = 8000. \t\t\t#psi\n", "Ss = 4000. \t\t\t#psi\n", "Ws = 25000. \t\t\t#psi\n", "angle = 30. \t\t\t#degrees\n", "L = 4. \t\t\t#in\n", "b = 1. \t\t\t#in\n", "\t\t\t\n", "# Calculations\n", "P = Ns*L*b/((math.cos(math.radians(2*angle)))**2)\n", "P1 = 2*Ss*L*b/(math.sin(math.radians(2*angle)))\n", "Pts = Ws*L*b\n", "e = P1/Pts\n", "\t\t\t\n", "# Results\n", "if (P<P1):\n", " print 'P = %.2f lb'%(round(P,-3))\n", "else:\n", " print 'P1 = %.2f lb'%(round(P1,-3))\n", "\n", "print 'efficiency of the joint = %.2f '%(e)\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "P1 = 37000.00 lb\n", "efficiency of the joint = 0.37 \n" ] } ], "prompt_number": 10 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 8.7 Page No : 167" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\t\t\t\n", "# Variables\n", "T = 15000 \t\t\t#psi\n", "h1 = 3 \t\t\t#in\n", "h2 = 2.5 \t\t\t#in\n", "t = 0.25 \t\t\t#in\n", "r = 5/16. \t\t\t#in\n", "d = 1. \t\t\t#in\n", "\t\t\t\n", "# Calculations\n", "P1 = T*(h1-d)*t/2.18\n", "P2 = T*h2*t/1.7\n", "if (P1<P2):\n", " print 'Safe axial load = %.f lb'%(P1)\n", "else: \n", " print 'Safe axial load = %.f lb'%(P2)\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Safe axial load = 3440 lb\n" ] } ], "prompt_number": 12 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 8.8 Page No : 174" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\t\t\t\n", "# Variables\n", "d = 16. \t\t\t#ft\n", "h = 24. \t \t\t#ft\n", "P = 160. \t\t\t#lb/cu ft\n", "hs1 = 8. \t\t\t#ft\n", "hs2 = 8. \t\t\t#ft\n", "hs3 = 8. \t\t\t#ft\n", "Tsmax = 5000. \t\t\t#psi\n", "\t\t\t\n", "# Calculations\n", "SW = round(P/1728,4)\n", "P8 = round(SW*hs1*12,2)\n", "P16 = round(SW*(hs1+hs2)*12,1)\n", "P24 = round(SW*(hs1+hs2+hs3)*12,1)\n", "t8 = (P8*d*12)/(2*Tsmax)\n", "t16 = P16*d*12/(2*Tsmax)\n", "t24 = P24*d*12/(2*Tsmax)\n", "\t\t\t\n", " \n", "# Results\n", "print 't8 = %.2f in'%(t8)\n", "print 't16 = %.2f in'%(t16)\n", "print 't24 = %.2f in'%(t24)\n", "\n", "# note : book answers are wrong. please check. " ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "t8 = 0.17 in\n", "t16 = 0.34 in\n", "t24 = 0.51 in\n" ] } ], "prompt_number": 19 } ], "metadata": {} } ] }