{ "metadata": { "name": "" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "Chapter 6: Mechanical Properties of Metal" ] }, { "cell_type": "heading", "level": 3, "metadata": {}, "source": [ "Example 6.1 Page No 140" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "E=110*10**3 #Young's modulus of Copper in MPa\n", "sigma=276.0 #Applied stress in MPa\n", "lo=305.0 #Original length in mm\n", "\n", "dl=sigma*lo/E\n", "\n", "print\"Elongation obtained is \",round(dl,2),\"mm\"\n", "\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Elongation obtained is 0.77 mm\n" ] } ], "prompt_number": 3 }, { "cell_type": "heading", "level": 3, "metadata": {}, "source": [ "Example 6.2 Page No 142" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "del_d=-2.5*10**-3 #Deformation in dia in mm\n", "d0=10.0 #Initial dia in mm\n", "v=0.34 #Poisson ratio for brass\n", "\n", "ex=del_d/d0\n", "ez=-ex/v\n", "E=97*10**3 #Modulus of elasticity in MPa\n", "sigma=ez*E\n", "F=sigma*math.pi*(d0**2)/4.0\n", "\n", "print\"Applied force is \",round(F,0),\"N\"\n", "\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Applied force is 5602.0 N\n" ] } ], "prompt_number": 7 }, { "cell_type": "heading", "level": 3, "metadata": {}, "source": [ "Example 6.3 Page No 146" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "si2=150 # in MPa\n", "si1=0\n", "e2=0.0016\n", "e1=0\n", "d0=12.8*10**-3 #Initial Diameter in m\n", "\n", "E=(si2-si1)/(e2-e1)\n", "\n", "A0=math.pi*d0**2/4.0\n", "sig=450*10**6 #tensile strength in MPa\n", "F=sig*A0\n", "l0=250 #Initial lengt in mm\n", "e=0.06 #strain\n", "dl=e*l0\n", "\n", "print\"Modulus of elasticity is \",round(E/10**3,1),\"GPa\"\n", "print\"From the graph the Yield strength is\",l0,\"MPa\"\n", "print\"Maximum load sustained is \",round(F,0),\"N/n\"\n", "print\"Change in length is \",dl,\"mm\"\n", "\n", "\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Modulus of elasticity is 93.8 GPa\n", "From the graph the Yield strength is 250 MPa\n", "Maximum load sustained is 57906.0 N/n\n", "Change in length is 15.0 mm\n" ] } ], "prompt_number": 12 }, { "cell_type": "heading", "level": 3, "metadata": {}, "source": [ "Example 6.4 Page No 153" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "di=12.8 #Initial dia in mm\n", "df=10.7 #Final dia in mm\n", "\n", "import math\n", "RA = ((di**2-df**2)/di**2)*100\n", "Ao=math.pi*di**2*10**-6/4.0\n", "sig=460*10**6 #Tensile strength\n", "\n", "F=sig*Ao\n", "\n", "Af=math.pi*df**2/4.0\n", "sig_t=F/Af\n", "\n", "print\"percent reduction in area is \",round(RA,0),\"%\"\n", "print\"True stress is \",round(sig_t,1),\"MPa\"\n", "\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "percent reduction in area is 30.0 %\n", "True stress is 658.3 MPa\n" ] } ], "prompt_number": 14 }, { "cell_type": "heading", "level": 3, "metadata": {}, "source": [ "Example 6.5 Page No 153" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "sig_t=415 #True stress in MPa\n", "et=0.1 #True strain\n", "K=1035.0 # In MPa\n", "\n", "n=(math.log(sig_t)-math.log(K))/math.log(et)\n", "\n", "print\"Strain - hardening coefficient is \",round(n,2)\n", "\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Strain - hardening coefficient is 0.4\n" ] } ], "prompt_number": 5 }, { "cell_type": "heading", "level": 3, "metadata": {}, "source": [ "Example 6.6 Page No 162" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "n=4.0 #No of points\n", "T1=520\n", "T2=512\n", "T3=515\n", "T4=522\n", "\n", "Tav=(T1+T2+T3+T4)/n\n", "s=(((T1-Tav)**2+(T2-Tav)**2+(T3-Tav)**2+(T4-Tav)**2)/(n-1))**(0.5)\n", "\n", "print\"The average Tensile strength is\",round(Tav,0),\"MPa\"\n", "print\"The standard deviation is\",round(s,1),\"MPa\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The average Tensile strength is 517.0 MPa\n", "The standard deviation is 4.6 MPa\n" ] } ], "prompt_number": 22 }, { "cell_type": "heading", "level": 3, "metadata": {}, "source": [ "Design Example 6.1 ,Page No 164" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "sig_y=310.0 #Minimum yield strength in MPa\n", "N=5.0 # Conservative factor of safety\n", "\n", "F=220000/2.0 #Two rods must support half of the total force\n", "sig_w=sig_y/N\n", "d=2*math.sqrt(F/(math.pi*sig_w))\n", "\n", "print\"Diameter of each of the two rods is \",round(d,1),\"mm\"\n", "\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Diameter of each of the two rods is 47.5 mm\n" ] } ], "prompt_number": 18 }, { "cell_type": "code", "collapsed": false, "input": [], "language": "python", "metadata": {}, "outputs": [] } ], "metadata": {} } ] }