{ "metadata": { "name": "", "signature": "sha256:087506e84c2c9ece60ca0c23e6e5e2f5e309357e67157657330423d5e748517d" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "Chapter 24 :Theories of Failure" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Problem 24.10,page no.1019" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from __future__ import division\n", "import math\n", "\n", "#Given\n", "#Variable declaration\n", "P=9*1000 #Axial pull in N\n", "F=4.5*1000 #Shear force in N \n", "sigmat_star=225 #Elastic limit in tension in N/sq.mm\n", "Sf=3 #Factor of safety \n", "mu=0.3 #Poisson's ratio \n", "sigma3=0 #third principle stress\n", "\n", "#Calculation\n", "sigmat=sigmat_star/Sf \n", "sigma=(P/(math.pi/4))\n", "tau=float(str(F/(math.pi/4))[:6])\n", "sigma1=float(str((tau)+int(round(math.sqrt((sigma/2)**2+tau**2),0)))[:7])\n", "sigma2=float(str((tau)-int(round(math.sqrt((sigma/2)**2+tau**2),0)))[:8])\n", "d=round(((((sigma1-sigma2)**2+(sigma2-sigma3)**2+(sigma3-sigma1)**2)/(2*(sigmat**2)))**(1/4)),3) \n", "\n", "#Result\n", "print\"Diameter of the bolt =\",d,\"mm\"\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Diameter of the bolt = 14.217 mm\n" ] } ], "prompt_number": 1 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Problem 24.12,page no.1027" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from __future__ import division\n", "import math\n", "#Given\n", "#Variable declaration\n", "d=1.2 #Diameter in m\n", "p=1.5 #Internal pressure in MN/sq.m\n", "sigmat_star=200 #Yield stress in MN/sq.m\n", "Sf=3 #Factor of safety\n", "\n", "#Calculation\n", "sigmat=sigmat_star/Sf #Permissible stress in simple tension in MN/sq.m\n", "\n", "#case(i):Thickness on the basis of Maximum principal stress theory\n", "t1=((p*d)/2)/sigmat*1e3\n", "\n", "#case(ii):Thickness on the basis of Maximum shear stress theory\n", "t2=((p*d)/2)/sigmat*1e3\n", "\n", "#case(iii):Thickness on the basis of Maximum shear strain energy theory\n", "t3=round(math.sqrt((((p*d/2)**2)+((p*d/4)**2)-((p*d/2)*(p*d/4)))/(sigmat**2)),4)\n", "\n", "#Result\n", "print \"Thickness of plate on the basis of maximum principal stress theory =\",\"%.1fmm\"%t1\n", "print \"Thickness of plate on the basis of maximum shear stress theory =\",\"%.1fmm\"%t2\n", "print \"Thickness of plate on the basis of maximum shear strain energy theory =\",\"%.4fmm\"%t3" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Thickness of plate on the basis of maximum principal stress theory = 13.5mm\n", "Thickness of plate on the basis of maximum shear stress theory = 13.5mm\n", "Thickness of plate on the basis of maximum shear strain energy theory = 0.0117mm\n" ] } ], "prompt_number": 2 }, { "cell_type": "code", "collapsed": false, "input": [], "language": "python", "metadata": {}, "outputs": [] } ], "metadata": {} } ] }