{ "metadata": { "name": "", "signature": "sha256:02d16750a95e9cb061b70a14a88598b538bc7e53305c21d4fa8042fd93a35729" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "Ch:19 Flywheel" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "exa 19-1 - Page 530" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from __future__ import division\n", "from math import sqrt, pi, cos, sin\n", "R=1200#\n", "b=300#\n", "t=150#\n", "N=500#\n", "m=7100*10**-9*b*t#\n", "Ar=b*t#\n", "Aa=Ar/4#\n", "C=(20280/t**2)+0.957+(Ar/Aa)#\n", "w=2*pi*N/60#\n", "V=w*R*10**-3#\n", "siga=2*10**3*m*V**2/(C*Aa*3)#\n", "theta=30*pi/180#\n", "alpha=30*pi/180#\n", "x1=10**3*m*(V**2)/(b*t)#\n", "y1=cos(theta)/(3*C*sin(alpha))#\n", "z1=2000*R*10**-3/(C*t)*((1/alpha)-(cos(theta)/sin(alpha)))#\n", "sigrr1=x1*(1-y1+z1)#\n", "theta=0*pi/180#\n", "x2=10**3*m*(V**2)/(b*t)#\n", "y2=cos(theta)/(3*C*sin(alpha))#\n", "z2=2000*R*10**-3/(C*t)*((1/alpha)-(cos(theta)/sin(alpha)))#\n", "sigrr2=x2*(1-y2-z2)#\n", "print \"axial stress is %0.2f MPa \"%(siga)#\n", "print \"\\ntensile stress for theta=30deg is %0.1f MPa \"%(sigrr1)#\n", "print \"\\ntensile stress for theta=0deg is %0.2f MPa \"%(sigrr2)#\n", "#The difference in the value of sigrr1 and sigrr2 is due to rounding-off of values." ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "axial stress is 12.76 MPa \n", "\n", "tensile stress for theta=30deg is 38.9 MPa \n", "\n", "tensile stress for theta=0deg is 31.74 MPa \n" ] } ], "prompt_number": 1 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "exa 19-2 - Page 530" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from math import asin, cos\n", "N=350#\n", "theta1=asin(sqrt((3-0.6)/4))#\n", "theta1=theta1*180/pi#\n", "theta2=(180)-theta1#\n", "#Ti=16000+6000*sind(3*theta)#\n", "#To=16000+3600*sind(theta)#\n", "a=-3600*(cos(pi/180*theta2)-cos(pi/180*theta1))#\n", "b=2000*(cos(pi/180*3*theta2)-cos(pi/180*3*theta1))#\n", "c=a+b#\n", "delU=c#\n", "Ks=0.05#\n", "w=2*pi*N/60#\n", "I=delU/(Ks*w**2)#\n", "V=25#\n", "Ir=I*0.95#\n", "R=V/w#\n", "Mr=Ir/R**2#\n", "rho=7150#\n", "t=sqrt(Mr*(10**6)/(2*pi*R*2*rho))#\n", "b=2*t#\n", "print \"t is %0.2f mm \"%(t)#\n", "print \"\\nb is %0.2f mm \"%(b)#\n", "print \"\\nR is %0.3f m \"%(R)#" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "t is 63.37 mm \n", "\n", "b is 126.74 mm \n", "\n", "R is 0.682 m \n" ] } ], "prompt_number": 2 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "exa 19-3 - Page 531" ] }, { "cell_type": "code", "collapsed": false, "input": [ "N=300#\n", "Ks=0.03#\n", "rho=7150#\n", "Kr=0.9#\n", "w=2*pi*N/60#\n", "WD=(300*2*pi)+(4*pi*200/4)#\n", "Tm=400#\n", "delU=pi*200/16#\n", "Ir=Kr*delU/(w**2*Ks)#\n", "R=Ir/(rho*1.5*0.1*0.1*2*pi)#\n", "R=R**(1/5)#\n", "t=0.1*R*1000#\n", "b=1.5*t#\n", "print \"t is %0.2f mm \"%(t)#\n", "print \"\\nb is %0.2f mm \"%(b)#\n", "print \"\\nR is %0.4f m \"%(R)#" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "t is 28.16 mm \n", "\n", "b is 42.24 mm \n", "\n", "R is 0.2816 m \n" ] } ], "prompt_number": 3 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "exa 19-4 - Page 532" ] }, { "cell_type": "code", "collapsed": false, "input": [ "d=20#\n", "t=12#\n", "Tus=450#\n", "Pmax=pi*d*t*Tus#\n", "WD=Pmax*t/2*10**-3#\n", "n=0.95#\n", "Wi=WD/n#\n", "delU=5*Wi/6#\n", "N=300#\n", "w=2*pi*N/60#\n", "Ks=0.2#\n", "I=delU/(Ks*w**2)#\n", "Ir=I*0.9#\n", "R=0.5#\n", "m=Ir/R**2#\n", "rho=7150#\n", "t=sqrt(m*10**6/(rho*2*pi*R*2))#\n", "b=2*t#\n", "print \"t is %0.1f mm \"%(t)#\n", "print \"\\nb is %0.1f mm \"%(b)#\n", "print \"\\nR is %0.1f m \"%(R)#" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "t is 26.9 mm \n", "\n", "b is 53.8 mm \n", "\n", "R is 0.5 m \n" ] } ], "prompt_number": 4 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "exa 19-5 - Page 533" ] }, { "cell_type": "code", "collapsed": false, "input": [ "U=(500*2*pi)+(3*pi*500/2)#\n", "Tm=U/(2*pi)#\n", "delU=2.25*pi*125/2#\n", "Ks=0.1#\n", "N=250#\n", "w=2*pi*N/60#\n", "I=delU/(Ks*w**2)#\n", "t=0.03#\n", "rho=7800#\n", "R=(I*2/(pi*rho*t))**(1/4)#\n", "V=R*w#\n", "v=0.3#\n", "sigmax=rho*V**2*(3+v)/8*10**-6#\n", "print \"R is %0.3f m \"%(R)#\n", "print \"\\nsigmax is %0.2f MPa \"%(sigmax)#\n", " " ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "R is 0.364 m \n", "\n", "sigmax is 0.29 MPa \n" ] } ], "prompt_number": 5 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "exa 19-6 - Page 534" ] }, { "cell_type": "code", "collapsed": false, "input": [ "N=1.5*8*60#\n", "l=200#\n", "t=1.5/2#\n", "W=350*10**3#\n", "WD=0.15*l*W*10**-6#\n", "n=0.9# #since frictional effect is 10%, effciency of system is 90%\n", "Wi=WD/n#\n", "L=400#\n", "delU=(L-(0.15*l))/(L)*10**3*Wi#\n", "Ks=0.12#\n", "w=2*pi*N/60#\n", "I=delU/(Ks*w**2)#\n", "Ir=I*0.9#\n", "R=0.7#\n", "m=Ir/R**2#\n", "rho=7150#\n", "t=sqrt(m*10**6/(rho*2*pi*R*1.5))#\n", "b=1.5*t#\n", "print \"t is %0.1f mm \"%(t)#\n", "print \"\\nb is %0.1f mm \"%(b)#" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "t is 24.8 mm \n", "\n", "b is 37.2 mm \n" ] } ], "prompt_number": 6 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "exa 19-7 - Page 535" ] }, { "cell_type": "code", "collapsed": false, "input": [ "N=144#\n", "#Let n be no. of punches/ min\n", "n=8#\n", "#Let t be timr for 1 punch\n", "t=60/n#\n", "theta=N/60*2*pi*0.6#\n", "T=2.1#\n", "U=T*theta#\n", "#Let U1 be revolution of crankshaft in t sec\n", "U1=t*N/60*2*pi#\n", "delU=(U1-theta)/U1*U*10**3#\n", "w=2*pi*1440/60#\n", "Ks=0.1#\n", "I=delU/(Ks*w**2)#\n", "Ir=I*0.9#\n", "rho=7100#\n", "\n", "R=Ir/(rho*0.2*0.1*2*pi)#\n", "R=R**(1/5)#\n", "t=0.1*R*1000#\n", "b=0.2*R*10**3#\n", "t=40#\n", "b=80#\n", "R=400#\n", "# printing data in scilab o/p window\n", "print \"t is %0.0f mm \"%(t)#\n", "print \"\\nb is %0.0f mm \"%(b)#\n", "print \"\\nR is %0.0f mm \"%(R)#" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "t is 40 mm \n", "\n", "b is 80 mm \n", "\n", "R is 400 mm \n" ] } ], "prompt_number": 7 } ], "metadata": {} } ] }