{ "metadata": { "name": "chapter 16 som.ipynb" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "Chapter 16:Riveted Joints" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Problem 16.1,Page no.366" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "\n", "#Initilization of variables\n", "\n", "t=1 #cm #thickness of plates\n", "sigma_t=150 #MPa #Working stress\n", "sigma_c=212.5 #MPa #crushing stress\n", "sigma_s=94.5 #MPa #shearing stress\n", "\n", "#Calculation (Part-1)\n", "\n", "#P_s=pi*4**-1*d**2*sigma_s #N #Shearing strength\n", "#After substituting values and further simplifying we get\n", "#P_s=pi*4**-1*d**2*94.5*10**6 #N \n", "\n", "#P_c=d*t*sigma_c #N #crushing strength\n", "#After substituting values and further simplifying we get\n", "#P_c=d*1*10**-2*212.5*10**6 #N \n", "\n", "#P_t=(p-d)*t*sigma_t #N #Strength of plate in tearing\n", "#After substituting values and further simplifying we get\n", "#P_t=(p-d)*1*10**-2*150*10**6\n", "\n", "#Now comparing strengths \n", "#P_s=P_c \n", "#pi*4**-1*d**2*94.5*10**6=d*1*10**-2*212.5*10**6\n", "d=1*10**-2*212.5*10**6*(pi*4**-1*94.5*10**6)**-1 #m #Diameter of rivet\n", "\n", "#Now comparing strengths \n", "#P_t=P_c\n", "#(p-d)*1*10**-2*150*10**6=d*1*10**-2*212.5*10**6\n", "#Afte further simplifying equation we get\n", "#(p-d)=1.4166*d\n", "p=(1.4166*d+d) #m #Pitch length of rivet\n", "\n", "P=p*sigma_t*10**6*t*10**-2 #N #Strength of solid plate #Answer for strength of solid plate is incorrect in textbook \n", "\n", "rho=(p-d)*p**-1*100 #Efficiency of the joint #Notification has been changed\n", "\n", "#Calculation (Part-2)\n", "\n", "#P_s=2*pi*4**-1*d**2*sigma_s #N #Shearing strength\n", "#After substituting values and further simplifying we get\n", "#P_s=2*pi*4**-1*d**2*94.5*10**6 #N \n", "\n", "#P_c=2*d*t*sigma_c #N #crushing strength\n", "#After substituting values and further simplifying we get\n", "#P_c=2*d*1*10**-2*212.5*10**6 #N \n", "\n", "#P_t=(p-d)*t*sigma_t #N #Strength of plate in tearing\n", "#After substituting values and further simplifying we get\n", "#P_t=(p-d)*1*10**-2*150*10**6\n", "\n", "#Now comparing strengths \n", "#P_s=P_c \n", "#2*pi*4**-1*d**2*94.5*10**6=2*d*1*10**-2*212.5*10**6\n", "d=1*10**-2*212.5*10**6*(pi*4**-1*94.5*10**6)**-1 #m #Diameter of rivet\n", "\n", "#Now comparing strengths \n", "#P_t=P_c\n", "#(p-d)*1*10**-2*150*10**6=2*d*1*10**-2*212.5*10**6\n", "#Afte further simplifying equation we get\n", "#(p-d)=2.833*d\n", "p_1=(2.833*d+d) #m #Pitch length of rivets in shearing strength of plate #Notification for pitch length has been changed\n", "\n", "rho_2=(p_1-d)*p_1**-1*100 #Efficiency of the joint #Notification has been changed\n", "\n", "#Result \n", "print\"The Efficiency of joint in single rivet is\",round(rho,2),\"%\"\n", "print\"The Efficiency of joint in double rivet is\",round(rho_2,2),\"%\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The Efficiency of joint in single rivet is 58.62 %\n", "The Efficiency of joint in double rivet is 73.91 %\n" ] } ], "prompt_number": 29 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Problem 16.2,Page no.367" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "\n", "#Initilization of variables\n", "\n", "p=7.5 #cm #Pitch of rivets\n", "t=1.5 #cm #Thickness of plate\n", "d=2.5 #cm #diameter of rivets\n", "sigma_t=400 #MPa #Working stress\n", "sigma_c=640 #MPa #crushing stress\n", "sigma_s=320 #MPa #shearing stress\n", "n=2 #No. of rivets\n", "\n", "#Calculation\n", "\n", "P_t=(p-d)*t*10**-4*sigma_t*10**6*10**-3 #N #Strength of plate in tearing\n", "P_s=n*pi*4**-1*d**2*10**-4*sigma_s*10**6*10**-3 #N #Shearing strength\n", "P_c=n*d*t*10**-4*sigma_c*10**6*10**-3 #N #crushing strength\n", "\n", "#Thus Minimum force that will rapture the joint is least of P_t,P_s,P_c i.e P_t\n", "\n", "#Result\n", "print\"Minimum force that will rapture the joint is\",round(P_t,2),\"N\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Minimum force that will rapture the joint is 300.0 N\n" ] } ], "prompt_number": 39 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Problem 16.3,Page no.367" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "\n", "#Initilization of variables\n", "\n", "d_1=2 #cm #Diameter of rivets\n", "p_1=6 #cm #Pitch of rivet\n", "d_2=3 #cm #Diameter of rivet\n", "p_2=8 #cm #Pitch of rivet\n", "sigma_t=120 #MPa #Working stress\n", "sigma_c=160 #MPa #crushing stress\n", "sigma_s=90 #MPa #shearing stress\n", "t=1.2 #cm #thickness of plate\n", "n=2 #No. of rivets\n", "\n", "#Calculation (part-1)\n", "\n", "P_t=(p_1-d_1)*t*10**-4*sigma_t*10**6 #N #Strength of plate in tearing\n", "P_s=n*pi*4**-1*d_1**2*10**-4*sigma_s*10**6 #N #Shearing strength\n", "P_c=n*d_1*t*10**-4*sigma_c*10**6 #N #crushing strength\n", "P=p_1*t*10**-4*sigma_t*10**6 #N #Strength of solid per pitch length\n", "\n", "rho_1=P_s*(P)**-1*100 #% #Efficiency of the joint\n", "\n", "#Calculation (part-2)\n", "\n", "P_t_2=(p_2-d_2)*t*10**-4*sigma_t*10**6 #N #Strength of plate in tearing\n", "P_s_2=n*pi*4**-1*d_2**2*10**-4*sigma_s*10**6 #N #Shearing strength\n", "P_c_2=n*d_2*t*10**-4*sigma_c*10**6 #N #crushing strength\n", "P_2=p_2*t*10**-4*sigma_t*10**6 #N #Strength of solid per pitch length\n", "\n", "rho_2=P_t_2*(P_2)**-1*100 #% #Efficiency of the joint\n", "\n", "#Result\n", "print\"First joint has higher Efficiency i.e\",round(rho_1,2),\"% than second joint\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "First joint has higher Efficiency i.e 65.45 % than second joint\n" ] } ], "prompt_number": 60 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Problem 16.4,Page no.368" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "\n", "#Initilization of variables\n", "\n", "t=18 #mm #thickness of plates\n", "sigma_t=100 #MPa #Tensile stress #Notification has been changed\n", "sigma_s=70 #MPa #Shearing stress #Notification has been changed\n", "\n", "#Calculations\n", "\n", "d=6*t**0.5 #mm #Diameter of rivet #Answer is in correct in textbook\n", "s=pi*4**-1*d**2*10**-6*sigma_s*10**6 #N #Strength of one rivet in single shear #Answer is in correct in textbook\n", "\n", "#Consider strip of joint equal to pitch p\n", "\n", "#S_1=(p-d)*t*10**-3*sigma_t*10**6 #Strength of plate against tearing along 1-1\n", "#After substituting values and further simplifying we get\n", "#S_1=1800*p-45900 (Equation 1)\n", " \n", "#S_2=(p-d)*t*10**-3*sigma_t*10**6+s #Strength of plate against tearing along 1-1\n", "#After substituting values and further simplifying we get\n", "#S_1=1800*p-56050.64 (Equation 2)\n", "\n", "#But the value of Equation 2 is smaller than Equation 1\n", "\n", "#Strength of rivets in single shear is\n", "S=4*s\n", "\n", "#Equating Equation 2 to shearing value\n", "#1800*p-56050.64=S\n", "p=(S+56050.64)*18000**-1 #cm #Pitch of rivet\n", "\n", "#Result\n", "print\"Diameter of rivets is\",round(d,2),\"mm\"\n", "print\"Pitch of rivet is\",round(p,2),\"cm\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "35625.6606917\n", "Diameter of rivets is 25.46 mm\n", "Pitch of rivet is 11.03 cm\n" ] } ], "prompt_number": 77 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Problem 16.5,Page no.369" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "\n", "#Initilization of variables\n", "\n", "t=12 #mm #Thickness of plate\n", "d=24 #mm #Diameter of rivets\n", "sigma_t=120 #MPa #stress in tension\n", "sigma_s=200 #MPa #stress in double shear\n", "sigma_b=200 #MPa #stress in Bearing\n", "n=1 #No. of rivet\n", "\n", "#Calculation\n", "\n", "#P_t=(p-d)*t*10**-4*sigma_t*10**6 #N #Strength of plate in tearing\n", "#After further simplifying we get\n", "#P_t=(p-24)*14400 #N \n", "\n", "P_s=n*pi*4**-1*d**2*10**-6*sigma_s*10**6 #N #Shearing strength of rivet in double shear\n", "\n", "P_b=n*d*10**-3*t*10**-3*sigma_b*10**6 #N #Bearing strength per pitch length\n", "\n", "#Now Equating P_t to P_s or P_b whichever is small\n", "#(p-24)*14400=P_b\n", "p=P_b*14400**-1+24*10**-1 #cm #Pitch of rivet\n", "p_min=2.5*d*10**-1 #cm #Minimum pitch\n", "\n", "#Now adopting 6.4 cm pitch\n", "\n", "rho=(p-d*10**-1)*p**-1*100\n", "\n", "#Result\n", "print\"Pitch of rivet is\",round(p,2),\"cm\"\n", "print\"Efficiency of joint is\",round(rho,2),\"%\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Pitch of rivet is 6.4 cm\n", "Efficiency of joint is 62.5 %\n" ] } ], "prompt_number": 90 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Problem 16.6,Page no.370" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "\n", "#Initilization of variables\n", "\n", "t=12 #mm #thickness of plate\n", "d=18 #mm #Diameter of rivet\n", "p=8 #cm #pitch of rivet\n", "sigma_t=460 #MPa #Tensile stress\n", "sigma_s=320 #MPa #shearing stress\n", "sigma_b=640 #MPa #bearing stress\n", "n=2 #No. of rivet\n", "\n", "#Calculation\n", "\n", "P_t=(p-d*10**-1)*t*10**-1*10**-4*sigma_t*10**6 #N #Strength of plate in tearing\n", "P_s=n*2*pi*4**-1*d**2*10**-6*sigma_s*10**6 #N #Shearing strength of rivet pr pitch length\n", "P_b=n*d*10**-3*t*10**-3*sigma_b*10**6 #N #Bearing strength per pitch length\n", "\n", "#The joint will fail at a pull of P_b\n", "\n", "S=p*t*sigma_t*10**6*10**-5 #N #strength of solid plate\n", "rho=P_b*S**-1*100 #Efficiency of joint\n", "\n", "#Result\n", "print\"Pull per pitch length at which joint will fail is\",round(P_b,2),\"N\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Pull per pitch lenght at which joint will fail is 276480.0 N\n" ] } ], "prompt_number": 102 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Problem 16.7,Page no.370" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "\n", "#Initilization of variables\n", "\n", "W=270 #KN #Load \n", "t=14 #mm #thickness of plate\n", "b=20 #cm #width of plate\n", "d=20 #mm #diameter of rivet\n", "sigma_s=70 #MPa #shear stress\n", "sigma_b=190 #MPa #stress in bearing\n", "sigma_t=110 #MPa #stress in tensile\n", "\n", "#Calculation\n", "\n", "S_1=1.75*pi*4**-1*b**2*10**-4*sigma_s*10**6 #strength of one rivet in double shear\n", "S_2=20*10**-3*t*10**-3*sigma_b*10**6\n", "\n", "n=W*10**3*S_1**-1\n", "\n", "#Adopt 7 rivets\n", "\n", "#The plates may tear along section 1-1\n", "W_1=(20-4)*10**-2*t*10**-3*sigma_t*10**6 #N #Permissible Load\n", "\n", "#The plates may tear along section 2-2,at the same time shearing the 4 rivets along 1-1 \n", "W_2=(20-2*2)*10**-2*t*10**-3*sigma_t*10**6+2*S_1 #N #Permissible Load\n", "\n", "#The plates may tear along section 3-3,at the same time shearing the rivets along 1-1 and 2-2\n", "W_3=(20-3*2)*10**-2*t*10**-3*sigma_t*10**6+4*S_1 #N #Permissible Load\n", "\n", "W_s=7*S_1 #N #Load to shear all the rivets \n", "W_c=7*S_2 #N #Load to crush all the rivets\n", "\n", "W_4=b*10**-2*t*10**-3*sigma_t*10**6 #N #Load carried by solid plate\n", "\n", "rho=W_1*W_4**-1*100 #% #Efficiency of joint\n", " \n", "#Result\n", "print\"Efficiency of joint is\",round(rho,2),\"%\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Efficiency of joint is 80.0 %\n" ] } ], "prompt_number": 131 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Problem 16.8,Page no.371" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "\n", "#Initilization of variables\n", "\n", "D=1.5 #cm #Diameter of boiler\n", "rho=75 #% #Efficiency of joint\n", "sigma_t=85 #MPa #stress in tension\n", "sigma_s=70 #MPa #stress in shear\n", "P=1 #MPa #Steam Pressure #Notification has been changed\n", "\n", "#Calculation\n", "\n", "t=P*10**6*D*(2*sigma_t*10**6*rho*10**-2)**-1*100\n", "\n", "#Adopt 12 mm thickness of plate\n", "t_1=12 #mm \n", "d=6*t_1**0.5\n", "\n", "#Adopt 21 mm diameter of rivet\n", "d_1=21 #mm\n", "\n", "#P_t=(p-d_1*10**-1)*t*10**-1*10**-4*sigma_t*10**6 #N #Strength of plate in tearing\n", "#After substituting values and further simplifying we get\n", "#P_t=(p-2.1)*10200 #N \n", "\n", "P_s=1.875*pi*4**-1*d_1**2*10**-6*2*sigma_s*10**6\n", "\n", "#(p-d_1*10**-1)*10200=P_s\n", "p=P_s*10200**-1+d_1*10**-1\n", "\n", "#Result\n", "print\"pitch of plate is\",round(p,2),\"cm\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "pitch of plate is 11.01 cm\n" ] } ], "prompt_number": 111 } ], "metadata": {} } ] }