{ "cells": [ { "cell_type": "markdown", "metadata": {}, "source": [ "# Chapter 7: Impact and Energy Analysis" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 7.1: Impact_Energy.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "clc;\n", "clear;\n", "mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-7.1 Page No.137\n');\n", "D=2; //[in] Diameter of bar\n", "W=500; //[lb] Weight\n", "h=1; //[in] Height from which the weight falls\n", "A=%pi*D^2/4; //[in^2] Area of cross section of bar\n", "L=10; //[in] Length of bar\n", "E=30*10^6; //[lb/in^2] Modulus of elasticity\n", "S=(W/A)+(W/A)*(1+(2*h*E*A/(L*W)))^(0.5); //[lb/in^2] Stress in the bar\n", "mprintf('\n Stress in the bar is %f lb/in^2.',S);\n", "Delta=S*L/E; //[in] Deflection\n", "mprintf('\n Deflecton in the bar is %f in.',Delta);" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 7.2: Velocity_and_Impact.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "clc;\n", "clear;\n", "mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-7.2 Page No.139\n');\n", "W=2000; //[lb] Weight of automobile\n", "L=36; //[in] Length of stop\n", "D=2; //[in] Diameter of steel bar\n", "V=5*5280*12/3600; //[in/s] Velocity of automobile\n", "A=%pi*D^2/4; //[in^2] Area of cross section of bar\n", "E=30*10^6; //[lb/in^2] Modulus of elasticity\n", "k=A*E/L; //[lb/in] Stiffness of the bar\n", "g=386; //[in/s^2] Acceleration due to gravity\n", "Delta=sqrt(2/k*W*(V^2/(2*g)+0)); //[in] Deflection\n", "mprintf('\n The deflection in the bar is %f in.',Delta);\n", "S=Delta*E/L; //[in] Stress in the bar\n", "//Note-In the book Delta=0.124 is used instead of Delta=0.123800\n", "mprintf('\n The stress in the bar is %f lb/in^2.',S);" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 7.3: Impact_on_Beam.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "clc;\n", "clear;\n", "mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-7.3 Page No.141\n');\n", "W=3000; //[lb] Weight of automobile\n", "L=40*12; //[in] Length of the beam\n", "I=64.2; //[in^4] Moment of inertia of the beam\n", "Sy=48000; //[lb/in^2] Yield strength of the beam\n", "c=8/2; //[in] Distance from the outermost fiber to neutral axis\n", "E=30*10^6; //[lb/in^2] Modulus of elasticity\n", "g=32.2; //[ft/s^2] Acceleration due to gravity\n", "M=I*Sy/c; //[lb*in] Moment at which beam will yield\n", "F=4*M/L; //[lb] Force at which beam will yield\n", "Delta=F*L^3/(48*E*I); //[in] Deflection\n", "KE=F*Delta/2; //[lb*in] Kinetic energy\n", "V=sqrt(2*g*KE/W); //[in/s] Velocity\n", "V=V/5280*3600; //[miles/hr] Velocity\n", "mprintf('\n At %f miles/hr velocity the beam will yield.',V);" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 7.4: Designing_for_Impact.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "clc;\n", "clear;\n", "mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-7.4 Page No.143\n');\n", "D=3/4; //[in] Diameter of the bolt\n", "At=0.334; //[in^2] Area of thread\n", "As=%pi*D^2/4; //[in^2] Area of shank\n", "//Note-In the book As=0.442 in^2 is used instead of As=0.4417865 in.\n", "E=30*10^6; //[lb/in^2] Modulus of elasticity\n", "Lt=2; //[in] Length of the thread\n", "Ls=6; //[in] Length of the shank\n", "h=0.03; //[in] Height from which the weight falls\n", "W=500; //[lb] Falling load\n", "Kt=At*E/Lt; //[lb/in] Stiffness of threaded portion\n", "Ks=As*E/Ls; //[lb/in] Stiffness of shank\n", "K=Kt*Ks/(Kt+Ks); //[lb/in] Overall stiffness\n", "Delta=(W/K)+(W/K)*sqrt(1+2*h*K/W); //[in] Deflection\n", "A=[Ls/E, Lt/E; 0.442, -0.334];\n", "b=[Delta; 0];\n", "S=A\b;\n", "S=max(S); //[lb/in^2] Maximum stress in the bolt\n", "//Note-In the book Delta=0.0048 in is used instead of Delta=0.0047619 in.\n", "mprintf('\n The maximum stress in this bolt is %f lb/in^2.',S);\n", "Ln=8; //[in] Length when shank has same area as threads\n", "Kn=At*E/Ln; //[lb/in] Stiffness\n", "Deltan=(W/Kn)+(W/Kn)*sqrt(1+2*h*Kn/W); //[in] Deflection\n", "S=Deltan*E/Ln; //[ln/in^2] Stress\n", "mprintf('\n If shank has the same area as threads then stress is %f lb/in^2 and deflection is %f in.',S,Deltan);" ] } ], "metadata": { "kernelspec": { "display_name": "Scilab", "language": "scilab", "name": "scilab" }, "language_info": { "file_extension": ".sce", "help_links": [ { "text": "MetaKernel Magics", "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md" } ], "mimetype": "text/x-octave", "name": "scilab", "version": "0.7.1" } }, "nbformat": 4, "nbformat_minor": 0 }