blob: 2810d5d77698dea662dda0e86313ae6a0d052785 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
|
clc;
clear;
mprintf('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-5.5 Page No.100\n');
Su=80000; //[lb/in^2] Ultimate strength
Sy=71000; //[lb/in^2] Yield strength
D=0.6; //[in] Diameter of shaft
d=0.5; //[in] Diameter of shaft at notch
r=0.05; //[in] Radius of notch
Z=%pi*d^3/16; //[in^3] Polar section modulus
Tmax=200; //[lb*in] Maximum load
Tmin=0; //[lb*in] Minimum load
Smax=Tmax/Z; //[lb/in^2] Maximum stress
Smin=Tmin/Z; //[lb/in^2] Minimum stress
Smean=(Smax+Smin)/2; //[lb/in^2] Mean stress
Salt=(Smax-Smin)/2; //[lb/in^2] Alternating stress
Csize=0.85; //[] Assume 0.5<D<2 in
Csurface=0.88; //[] Machined surface Figure 5.7b
Ctype=0.6; //[] Torsional stress
Sn=Csize*Csurface*Ctype*(0.5*Su); //[lb/in^2] Modified endurance limit
Kt=1.32; //[] (D/d)=1.2, (r/d)=0.1 from Appendix 6c
N=inv(Smean/(0.5*Sy)+Kt*Salt/Sn); //[] Safety factor
mprintf('\n The factor of safety for this design is %f',N);
|
