{ "metadata": { "name": "", "signature": "sha256:a847652c7729f38097f73bfa8bb0c1fa136b92fa8a1c23926acab13f8bc56911" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "Chapter 2:Elastic Constants" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Problem 2.1,page no.60" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from __future__ import division\n", "import math\n", "\n", "#Given\n", "#Variable declaration\n", "L=4*(10**3) #Length of the bar in mm\n", "b=30 #Breadth of the bar in mm\n", "t=20 #Thickness of the bar in mm\n", "P=30*(10**3) #Axial pull in N\n", "E=2e5 #Young's modulus in N/sq.mm\n", "mu=0.3 #Poisson's ratio\n", "\n", "#Calculation\n", "A=b*t #Area of cross-section in sq.mm\n", "long_strain=P/(A*E) #Longitudinal strain \n", "delL=long_strain*L #Change in length in mm\n", "lat_strain=mu*long_strain #Lateral strain\n", "delb=b*lat_strain #Change in breadth in mm\n", "delt=t*lat_strain #Change in thickness in mm\n", "\n", "#Result\n", "print \"change in length =\",delL,\"mm\"\n", "print \"change in breadth =\",delb,\"mm\"\n", "print \"change in thickness =\",delt,\"mm\"\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "change in length = 1.0 mm\n", "change in breadth = 0.00225 mm\n", "change in thickness = 0.0015 mm\n" ] } ], "prompt_number": 2 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Problem 2.2,page no.61" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#Given\n", "#Variable declaration\n", "L=30 #Length in cm\n", "b=4 #Breadth in cm\n", "d=4 #Depth in cm\n", "P=400*(10**3) #Axial compressive load in N\n", "delL=0.075 #Decrease in length in cm\n", "delb=0.003 #Increase in breadth in cm\n", "\n", "#Calculation\n", "A=(b*d)*1e2 #Area of cross-section in sq.mm\n", "long_strain=delL/L #Longitudinal strain\n", "lat_strain=delb/b #Lateral strain\n", "mu=lat_strain/long_strain #Poisson's ratio\n", "E=int((P)/(A*long_strain)) #Young's modulus\n", "\n", "#Result\n", "print \"Poisson's ratio =\",mu\n", "print \"Young's modulus = %.e N/mm^2\"%E\n", "\n", "\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Poisson's ratio = 0.3\n", "Young's modulus = 1e+05 N/mm^2\n" ] } ], "prompt_number": 2 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Problem 2.3,page no.63" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#Given\n", "#Variable declaration\n", "L=4000 #Length of the bar in mm\n", "b=30 #Breadth of the bar in mm\n", "t=20 #Thickness of the bar in mm\n", "mu=0.3 #Poisson's ratio\n", "delL=1.0 #delL from problem 2.1\n", "\n", "#Calculation\n", "ev=(delL/L)*(1-2*mu) #Volumetric strain \n", "V=L*b*t #Original volume in mm^3\n", "delV=ev*V #Change in volume in mm^3\n", "F=int(V+delV) #Final volume in mm^3\n", "\n", "#Result\n", "print \"Volumetric strain =\",ev\n", "print \"Final volume =\",F,\"mm^3\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Volumetric strain = 0.0001\n", "Final volume = 2400240 mm^3\n" ] } ], "prompt_number": 3 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Problem 2.4,page no.63" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from __future__ import division\n", "#Given\n", "#Variable declaration\n", "L=300 #Length in mm\n", "b=50 #Width in mm\n", "t=40 #Thickness in mm\n", "P=300*10**3 #Pull in N\n", "E=2*10**5 #Young's modulus in N/sq.mm\n", "mu=0.25 #Poisson's ratio\n", "\n", "#Calculation\n", "V=L*b*t #Original volume in mm^3\n", "Area=b*t #Area in sq.mm \n", "stress=P/Area #Stress in N/sq.mm \n", "ev=(stress/E)*(1-2*mu) #Volumetric strain \n", "delV=int(ev*V) #Change in volume in mm^3 \n", "\n", "#Result\n", "print \"Change in volume =\",delV,\"mm^3\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ " Change in volume = 225 mm^3\n" ] } ], "prompt_number": 5 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Problem 2.7,page no.69" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "\n", "#Given\n", "#Variable declaration\n", "L=5*10**3 #Length in mm\n", "d=30 #Diameter in mm\n", "P=50*10**3 #Tensile load in N\n", "E=2e5 #Young's modulus in N/sq.mm\n", "mu=0.25 #Poisson's ratio\n", "\n", "#Calculation\n", "V=int(round((math.pi*d**2*L)/4,-2)) #Volume in mm^3 \n", "e=P*4/(math.pi*(d**2)*E) #Strain of length\n", "delL=round(e*L,3) #Change in length in mm\n", "lat_strain=round(mu*round(e,7),7) #Lateral strain \n", "deld=lat_strain*d #Change in diameter in mm\n", "delV=round(V*(0.0003536-(2*lat_strain)),2) #Change in volume in mm^3\n", "\n", "#Result\n", "print \"Change in length =\",delL,\"mm\"\n", "print \"Change in diameter =\",deld,\"mm\"\n", "print \"Change in volume =\",delV,\"mm^3\"\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Change in length = 1.768 mm\n", "Change in diameter = 0.002652 mm\n", "Change in volume = 624.86 mm^3\n" ] } ], "prompt_number": 7 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Problem 2.10,page no.79" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#Given\n", "#Variable declaration\n", "E=1.2e5 #Young's modulus in N/sq.mm\n", "C=4.8e4 #Modulus of rigidity in N/sq.mm\n", "\n", "#Calculation\n", "mu=(E/(2*C))-1 #Poisson's ratio \n", "K=int(E/(3*(1-2*mu))) #Bulk modulus in N/sq.mm\n", "\n", "#Result\n", "print \"Poisson's ratio =\",mu\n", "print \"Bulk modulus = %.0e N/mm^2\"%K\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Poisson's ratio = 0.25\n", "Bulk modulus = 8e+04 N/mm^2\n" ] } ], "prompt_number": 8 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Problem 2.11,page no.79" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#Given\n", "#Variable declaration\n", "A=8*8 #Area of section in sq.mm\n", "P=7000 #Axial pull in N\n", "Ldo=8 #Original Lateral dimension in mm\n", "Ldc=7.9985 #Changed Lateral dimension in mm\n", "C=0.8e5 #modulus of rigidity in N/sq.mm\n", "\n", "#Calculation\n", "lat_strain=(Ldo-Ldc)/Ldo #Lateral strain\n", "sigma=P/A #Axial stress in N/sq.mm\n", "mu=round(1/((sigma/lat_strain)/(2*C)-1),3) #Poisson's ratio\n", "E=round((sigma/lat_strain)/((sigma/lat_strain)/(2*C)-1),-1) #Modulus of elasticity in N/sq.mm\n", "\n", "#Result\n", "print \"Poisson's ratio =\",mu\n", "print \"Modulus of elasticity = %.4e N/mm^2\"%E\n", "\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Poisson's ratio = 0.378\n", "Modulus of elasticity = 2.2047e+05 N/mm^2\n" ] } ], "prompt_number": 9 }, { "cell_type": "code", "collapsed": false, "input": [], "language": "python", "metadata": {}, "outputs": [] } ], "metadata": {} } ] }