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Diffstat (limited to 'Mechanical_Metallurgy_by_George_E._Dieter/Chapter_12.ipynb')
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diff --git a/Mechanical_Metallurgy_by_George_E._Dieter/Chapter_12.ipynb b/Mechanical_Metallurgy_by_George_E._Dieter/Chapter_12.ipynb deleted file mode 100755 index ac9b05ec..00000000 --- a/Mechanical_Metallurgy_by_George_E._Dieter/Chapter_12.ipynb +++ /dev/null @@ -1,346 +0,0 @@ -{
- "cells": [
- {
- "cell_type": "markdown",
- "metadata": {},
- "source": [
- "# Chapter 12: Fatigue of Metals"
- ]
- },
- {
- "cell_type": "markdown",
- "metadata": {
- "collapsed": true
- },
- "source": [
- "### Example 12.1, Mean Stress, Page No. 387"
- ]
- },
- {
- "cell_type": "code",
- "execution_count": 1,
- "metadata": {
- "collapsed": false
- },
- "outputs": [
- {
- "name": "stdout",
- "output_type": "stream",
- "text": [
- "\n",
- "Bar Diameter = 1.45673 in\n"
- ]
- }
- ],
- "source": [
- "from math import pi\n",
- "from math import sqrt\n",
- "\n",
- "#variable declaration\n",
- "sigma_u=158; # in ksi\n",
- "sigma0=147; # in ksi\n",
- "sigma_e=75; # in ksi\n",
- "l_max=75; # in ksi\n",
- "l_min=-25; # in ksi\n",
- "sf=2.5;\n",
- "\n",
- "#calculation\n",
- "sigma_m=(l_max+l_min)/2;\n",
- "sigma_a=(l_max-l_min)/2;\n",
- "sigma_e=sigma_e/sf;\n",
- "A=sigma_a/sigma_e+sigma_m/sigma_u;\n",
- "D=sqrt(4*A/pi);\n",
- "\n",
- "#result\n",
- "print('\\nBar Diameter = %g in')%(D);"
- ]
- },
- {
- "cell_type": "markdown",
- "metadata": {},
- "source": [
- "### Example 12.2, Low Cycle Fatigue, Page No. 391"
- ]
- },
- {
- "cell_type": "code",
- "execution_count": 2,
- "metadata": {
- "collapsed": false
- },
- "outputs": [
- {
- "name": "stdout",
- "output_type": "stream",
- "text": [
- "\n",
- "d_e_e = 0.000681818\n",
- "d_e_p = 0.000608182\n",
- "Number of Cycles = 48884 cycles\n"
- ]
- }
- ],
- "source": [
- "\n",
- "\n",
- "#variable declaration\n",
- "sigma_b=75.0;\n",
- "e_b=0.000645;\n",
- "e_f=0.3;\n",
- "E=22*10**4;\n",
- "c=-0.6;\n",
- "\n",
- "#calculation\n",
- "d_e_e=float(2*sigma_b/E);\n",
- "d_e_p=2*e_b-d_e_e;\n",
- "N=((d_e_p/(2*e_f))**(1/c))/2;\n",
- "\n",
- "#result\n",
- "print('\\nd_e_e = %g\\nd_e_p = %g\\nNumber of Cycles = %g cycles')%(d_e_e,d_e_p,N);"
- ]
- },
- {
- "cell_type": "markdown",
- "metadata": {},
- "source": [
- "### Example 12.3, Fatigue Crack Proportion, Page No. 401"
- ]
- },
- {
- "cell_type": "code",
- "execution_count": 3,
- "metadata": {
- "collapsed": false
- },
- "outputs": [
- {
- "name": "stdout",
- "output_type": "stream",
- "text": [
- "Fatigue Cycles = 261417 cycles\n"
- ]
- }
- ],
- "source": [
- "from math import pi\n",
- "\n",
- "#variable declaration\n",
- "ai=0.5;\n",
- "ai=ai*10**-3; #conversion to m\n",
- "sigma_max=180.0;\n",
- "Kc=100.0;\n",
- "alpha=1.12;\n",
- "p=3.0;\n",
- "A=6.9*10**-12;\n",
- "\n",
- "#calculation\n",
- "af=(Kc/(sigma_max*alpha))**2/pi;\n",
- "Nf=float(af**(1-(p/2))-ai**(1-(p/2)))/float((1-p/2)*A*(sigma_max**3)*(pi**(p/2))*(alpha**p));\n",
- "\n",
- "#result\n",
- "print('Fatigue Cycles = %g cycles')%(Nf);"
- ]
- },
- {
- "cell_type": "markdown",
- "metadata": {},
- "source": [
- "### Example 12.4, Stress Concentration of Fatigue, Page No. 404"
- ]
- },
- {
- "cell_type": "code",
- "execution_count": 4,
- "metadata": {
- "collapsed": false
- },
- "outputs": [
- {
- "name": "stdout",
- "output_type": "stream",
- "text": [
- "\n",
- "Mean Stress = 25464.8 psi\n",
- "Fluctuating Bending Stress = 33658.4 psi\n",
- "Effective Maximum Stress = 59123.2 psi\n",
- "Effective Minimum Stress = 8193.63 psi\n",
- "sigma_a = 39834.1 psi\n",
- "\n",
- "\n",
- "Note: Calculation Errors in the book\n"
- ]
- }
- ],
- "source": [
- "\n",
- "\n",
- "from math import sqrt\n",
- "from math import pi\n",
- "\n",
- "#variable declaration\n",
- "rho=0.0004;\n",
- "S_u=190000;\n",
- "M=200;\n",
- "Pm=5000;\n",
- "D=0.5;\n",
- "dh=0.05;\n",
- "r=dh/2;\n",
- "Kt=2.2;\n",
- "\n",
- "#calculation\n",
- "Kf=1+(Kt-1)/(1+sqrt(rho/r));\n",
- "q=(Kf-1)/(Kt-1);\n",
- "A=pi/4*D**2;\n",
- "sigma_m=Pm/A;\n",
- "I=pi/64*D**4;\n",
- "sigma_a=Kf*((M*D)/(2*I));\n",
- "sigma_max=sigma_a+sigma_m;\n",
- "sigma_min=sigma_a-sigma_m;\n",
- "sigma_e=S_u/2;\n",
- "sigma_a1=sigma_e/Kf*(1-sigma_m/S_u);\n",
- "\n",
- "#result\n",
- "print('\\nMean Stress = %g psi\\nFluctuating Bending Stress = %g psi\\nEffective Maximum Stress = %g psi\\nEffective Minimum Stress = %g psi\\nsigma_a = %g psi\\n\\n\\nNote: Calculation Errors in the book')%(sigma_m,sigma_a,sigma_max,sigma_min,sigma_a1);\n"
- ]
- },
- {
- "cell_type": "markdown",
- "metadata": {},
- "source": [
- "### Example 12.5, Infinite Life Design, Page No. 422"
- ]
- },
- {
- "cell_type": "code",
- "execution_count": 5,
- "metadata": {
- "collapsed": false
- },
- "outputs": [
- {
- "name": "stdout",
- "output_type": "stream",
- "text": [
- "\n",
- "Fatigue Limit = 14245.3 psi\n"
- ]
- }
- ],
- "source": [
- "\n",
- "#variable declaration\n",
- "Kt=1.68;\n",
- "q=0.9;\n",
- "sigma_ed=42000;\n",
- "Cs=0.9;\n",
- "Cf=0.75;\n",
- "Cz=0.81;\n",
- "\n",
- "#calculation\n",
- "Kf=q*(Kt-1)+1;\n",
- "sigma_e=sigma_ed*Cs*Cf*Cz;\n",
- "sigma_en=sigma_e/Kf;\n",
- "\n",
- "#result\n",
- "print('\\nFatigue Limit = %g psi')%(sigma_en);"
- ]
- },
- {
- "cell_type": "markdown",
- "metadata": {},
- "source": [
- "### Example 12.6, Local Strain method, Page No. 424"
- ]
- },
- {
- "cell_type": "code",
- "execution_count": 1,
- "metadata": {
- "collapsed": false,
- "scrolled": true
- },
- "outputs": [
- {
- "name": "stdout",
- "output_type": "stream",
- "text": [
- "\n",
- "Number of cycles = 14785.5 cycles\n",
- "Fatigue damage per cycle = 6.7634e-05\n",
- "Number of cycles with correction of mean stress= 129289 cycles\n",
- "Fatigue damage per cycle with correction of mean stress= 7.7346e-06 damage per year\n",
- "Shaft will fail in 2.2446 days\n"
- ]
- }
- ],
- "source": [
- "\n",
- "from scipy.optimize import fsolve\n",
- "\n",
- "#variable declaration\n",
- "K=189;\n",
- "n=0.12;\n",
- "ef=1.06;\n",
- "sigma_f=190;\n",
- "b=-0.08;\n",
- "c=-0.66;\n",
- "E=30000000.0;\n",
- "E=E/1000; #conversion to ksi\n",
- "s=200.0;\n",
- "sigma_m=167.0;\n",
- "sigma_a=17.0;\n",
- "se=s**2/E;\n",
- "\n",
- "#calculation\n",
- "def f(ds):\n",
- " return (ds**2)/(2*E)+(ds**((1+n)/n))/((2*K)**(1/n))-se/2;\n",
- "ds=fsolve(f,1)\n",
- "de=se/ds;\n",
- "def f1(N2):\n",
- " return (N2**(b))*(sigma_f/E)+ef*(N2**(c))-de/2;\n",
- "N2=fsolve(f1,1);\n",
- "N_1=N2/2;\n",
- "de_e2=sigma_a/E;\n",
- "def f2(N2):\n",
- " return (N2**b)*((sigma_f-sigma_m)/E)+ef*(N2**c)-de_e2;\n",
- "N2=fsolve(f2,1);\n",
- "N_2=N2/2;\n",
- "C_pd=2*60*60*8;\n",
- "f=N_2/C_pd;\n",
- "\n",
- "#result\n",
- "print('\\nNumber of cycles = %g cycles\\nFatigue damage per cycle = %g\\nNumber of cycles with correction of mean stress= %g cycles\\nFatigue damage per cycle with correction of mean stress= %g damage per year\\nShaft will fail in %g days')%(N_1,1/N_1,N_2,1/N_2,f);\n"
- ]
- },
- {
- "cell_type": "code",
- "execution_count": null,
- "metadata": {
- "collapsed": true
- },
- "outputs": [],
- "source": []
- }
- ],
- "metadata": {
- "kernelspec": {
- "display_name": "Python 2",
- "language": "python",
- "name": "python2"
- },
- "language_info": {
- "codemirror_mode": {
- "name": "ipython",
- "version": 2
- },
- "file_extension": ".py",
- "mimetype": "text/x-python",
- "name": "python",
- "nbconvert_exporter": "python",
- "pygments_lexer": "ipython2",
- "version": "2.7.9"
- }
- },
- "nbformat": 4,
- "nbformat_minor": 0
-}
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