{ "metadata": { "name": "", "signature": "sha256:35167c2920a96b28d2f9772d7854ca2ec822d5efce1d68ac1a2ac93b9d95fe9f" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "Chapter 2: Axially Loaded Members" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 2.1, page no. 72" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "import math \n", "\n", "#initialisation\n", "\n", "W = 2.0 #lb\n", "b = 10.5 #inch\n", "c = 6.4 #inch\n", "k = 4.2 #inch\n", "p = 1.0/16.0 #inch\n", "\n", "#calculation\n", "\n", "n = (W*b)/(c*k*p) #inch\n", "\n", "#result\n", "\n", "print \" No. of revolution required = \", n, \"revolutions\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ " No. of revolution required = 12.5 revolutions\n" ] } ], "prompt_number": 1 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 2.2, page no. 74" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "\n", "import math \n", "import numpy\n", "\n", "#initialisation\n", "\n", "Fce_ = 2.0 #dummy variable\n", "Fbd_ = 3.0 #dummy variable \n", "Lbd = 480.0 #mm\n", "Lce = 600.0 #mm\n", "E = 205e6 #205Gpa\n", "Abd = 1020.0 #mm\n", "Ace = 520.0 #mm\n", "\n", "#calculation\n", "Dbd_ = (Fbd_*Lbd)/(E*Abd) #dummy variable\n", "Dce_ = (Fce_*Lce)/(E*Ace) #dummy variable\n", "Da = 1 #limiting value\n", "P = ((((450+225)/225)*(Dbd_ + Dce_) - Dce_ )**(-1)) * Da \n", "Fce = 2*P # Real value in newton\n", "Fbd = 3*P #real value in newton\n", "Dbd = (Fbd*Lbd)/(E*Abd) #print lacement in mm\n", "Dce = (Fce*Lce)/(E*Ace) # print lacement in mm\n", "a = numpy.degrees(numpy.arctan(((Da+Dce)/675))) #alpha in degree\n", "\n", "#result\n", "print \"alpha = \", round(a,2), \"degree\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "alpha = 0.11 degree\n" ] } ], "prompt_number": 3 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 2.3, page no. 80" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "\n", "import math \n", "\n", "#initialisation\n", "P1 = 2100.0 #lb\n", "P2 = 5600.0 #lb\n", "b = 25.0 #inch\n", "a = 28.0 #inch\n", "A1 = 0.25 #inch^2\n", "A2 = 0.15 #inch^2\n", "L1 = 20.0 #inch\n", "L2 = 34.8 #inch\n", "E = 29e6 #29Gpa\n", "\n", "#Calculations\n", "P3 = (P2*b)/a \n", "Ra = P3-P1\n", "N1 = -Ra \n", "N2 = P1 \n", "D = ((N1*L1)/(E*A1)) + ((N2*L2)/(E*A2)) #print lacement\n", "\n", "#Result\n", "print \"Downward print lacement is = \", D, \"inch\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Downward print lacement is = 0.0088 inch\n" ] } ], "prompt_number": 4 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 2.6, page no. 90" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "\n", "import math \n", "\n", "#Numerical calculation of allowable load\n", "\n", "d1 = 4.0 #mm\n", "d2 = 3.0 #mm\n", "A1 = (math.pi*(d1**2))/4 #area\n", "A2 = (math.pi*(d2**2))/4 #area\n", "L1 = 0.4 #meter\n", "L2 = 0.3 #meter\n", "E1 = 72e9 #Gpa\n", "E2 = 45e9 #Gpa\n", "f1 = L1/(E1*A1) * 1e6 # To cpmpensate for the mm**2\n", "f2 = L2/(E2*A2) * 1e6 \n", "s1 = 200e6 #stress\n", "s2 = 175e6 #stress\n", "\n", "#Calculations\n", "P1 = ( (s1*A1*(4*f1 + f2))/(3*f2) ) * 1e-6 # To cpmpensate for the mm**2\n", "P2 = ( (s2*A2*(4*f1 + f2))/(6*f1) ) * 1e-6 \n", "\n", "#Result\n", "print \"Newton Minimum allowable stress aomong the two P1 and P2 is smaller one, therefore MAS = \", P2" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Newton Minimum allowable stress aomong the two P1 and P2 is smaller one, therefore MAS = 1264.49104307\n" ] } ], "prompt_number": 5 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 2.10, page no. 113" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "\n", "import math \n", "\n", "#initialisation\n", "P = 90000.0 #newton\n", "A = 1200e-6 # meter^2\n", "s_x = -P/A #stress\n", "t_1 = 25.0 #for the stresses on ab and cd plane\n", "\n", "#Calculations\n", "s_1 = s_x*(math.cos(math.radians(t_1))**2)\n", "T_1 = -s_x*math.cos(math.radians(t_1))*math.sin(math.radians(t_1))\n", "t_2 = -65.0 #for the stresses on ad and bc plane\n", "s_2 = s_x*(math.cos(math.radians(t_2))**2)\n", "T_2 = -s_x*math.cos(math.radians(t_2))*math.sin(math.radians(t_2))\n", "\n", "#Result\n", "print \"The normal and shear stresses on the plane ab and cd are\", round((T_1/1E+6),2), round((s_1/1E+6),2), \"MPa respecively\" \n", "print \"respecively The normal and shear stresses on the plane ad and bc are\", round((T_2/1E+6),2), round((s_2/1E+6),2), \"MPa respecively\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The normal and shear stresses on the plane ab and cd are 28.73 -61.6 MPa respecively\n", "respecively The normal and shear stresses on the plane ad and bc are -28.73 -13.4 MPa respecively\n" ] } ], "prompt_number": 4 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 2.11, page no. 114" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "\n", "import math \n", "\n", "# Value of s_x based on allowable stresses on glued joint\n", "\n", "#initialisation\n", "s_t = -750.0 #psi\n", "t = -50.0 #degree\n", "T_t = -500.0 #psi\n", "\n", "sg_x_1 = s_t/(math.cos(math.radians(t))**2)\n", "sg_x_2 = -T_t/(math.cos(math.radians(t))*math.sin(math.radians(t)))\n", "\n", "# Value of s_x based on allowable stresses on plastic\n", "\n", "sp_x_1 = -1100.0 #psi\n", "T_t_p = 600.0 #psi\n", "t_p = 45.0 #degree\n", "sp_x_2 = -T_t_p/(math.cos(math.radians(t_p))*math.sin(math.radians(t_p)))\n", "\n", "# Minimum width of bar\n", "\n", "P = 8000.0 #lb\n", "A = P/sg_x_2\n", "b_min = math.sqrt(abs(A)) #inch\n", "print \"The minimum width of the bar is\", round(b_min,2), \"inch\"\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The minimum width of the bar is 2.81 inch\n" ] } ], "prompt_number": 1 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 2.15, page no. 126" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "import math \n", "#Bolt with reduced shank diameter\n", "\n", "#initialisation\n", "g = 1.50 # inch\n", "d = 0.5 #inch\n", "t = 0.25 #inch\n", "d_r = 0.406 #inch\n", "L = 13.5 #inch\n", "\n", "#calculation\n", "ratio = ((g*(d**2))/(((g-t)*(d_r**2))+(t*(d**2)))) #U2/U1\n", "\n", "print \"The energy absorbing capacity of the bolts with reduced shank diameter\", round(ratio,2)\n", "ratio_1 = ( (((L-t)*(d_r**2))+(t*(d**2))) / ((2*(g-t)*(d_r**2))+2*(t*(d**2))) ) #U3/2U1\n", "print \"The energy absorbing capacity of the long bolts\", round(ratio_1,2)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The energy absorbing capacity of the bolts with reduced shank diameter 1.4\n", "The energy absorbing capacity of the long bolts 4.18\n" ] } ], "prompt_number": 3 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ " Example 2.16, page no. 133" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "\n", "import math \n", "\n", "#initialisation\n", "# Maximum elongation\n", "M = 20 #kg\n", "g = 9.81 #m/s^2\n", "L = 2 #meter\n", "E = 210e9 #210Gpa\n", "h = 0.15 #meter\n", "diameter = 0.015 #milimeter\n", "\n", "#Calculations & Result\n", "A = (math.pi/4)*(diameter**2) #area\n", "D_st = ((M*g*L)/(E*A)) \n", "D_max = D_st*(1+(1+(2*h/D_st))**0.5) \n", "D_max_1 = math.sqrt(2*h*D_st) # another approach to find D_max\n", "i = D_max / D_st # Impact factor\n", "print \"Maximum elongation is\",round((D_max/1E-3),2), \"mm\" # Maximum tensile stress\n", "s_max = (E*D_max)/L #Maximum tensile stress\n", "s_st = (M*g)/A #static stress\n", "i_1 = s_max / s_st #Impact factor \n", "print \"Maximum tensile stress is \", round((s_max/1E+6),2), \"MPa\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Maximum elongation is 1.79 mm\n", "Maximum tensile stress is 188.13 MPa\n" ] } ], "prompt_number": 7 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 2.18, page no. 148" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "\n", "import math \n", "\n", "\n", "#initialisation\n", "P1 = 108000.0 #Newton\n", "P2 = 27000.0 #Newton\n", "L = 2.2 #meter\n", "A = 480.0 #mm^2\n", "\n", "\n", "#calculations\n", "\n", "# Displacement due to load P1 acting alone\n", "s = (P1/A) #stress in MPa\n", "e = (s/70000) + (1/628.2)*((s/260)**10) #strain\n", "D_b = e*L*1e3 #elongation in mm\n", "print \"elongation when only P1 load acting is = \", round(D_b,2), \" mm\"\n", "\n", "# Displacement due to load P2 acting alone\n", "s_1 = (P2/A) #stress in MPa\n", "e_1 = (s_1/70000) + (1/628.2)*((s_1/260)**10) #strain\n", "D_b_1 = e_1*(L/2)*1e3 #elongation in mm (no elongation in lower half)\n", "print \"elongation when only P2 load acting is = \", round(D_b_1,2), \" mm\"\n", "\n", "# Displacement due to both load acting simonmath.taneously\n", "#upper half\n", "s_2 = (P1/A) #stress in MPa\n", "e_2 = (s_2/70000) + (1/628.2)*((s_2/260)**10) #strain\n", "\n", "#lower half\n", "s_3 = (P1+P2)/A #stress in MPa\n", "e_3 = (s_3/70000) + (1/628.2)*((s_3/260)**10) #strain\n", "D_b_2 = ((e_2*L)/2 + (e_3*L)/2) * 1e3 # elongation in mm\n", "print \"elongation when P1 and P2 both loads are acting is = \", round(D_b_2,2), \" mm\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "elongation when only P1 load acting is = 7.9 mm\n", "elongation when only P2 load acting is = 0.88 mm\n", "elongation when P1 and P2 both loads are acting is = 12.21 mm\n" ] } ], "prompt_number": 3 } ], "metadata": {} } ] }