Thursday, January 14, 2016

HP 15C: Soderberg’s Equation for Fatigue



HP 15C: Soderberg’s Equation for Fatigue

Source:  Step by Step Solutions for your HP Calculator: Engineering Applications.  HP-32S.  Hewlett Packard.  Corvallis, OR.  1988  pg. 52-54




Equation:

Syp/FS = (Smax + Smin)/2 + K * (Syp/Se) * ((Smax – Smin)/2)

Variables:

R0 = Syp = yield point stress
R1 = Se = endurance stress reversed bending tests
R2 = Smax = maximum applied stress
R3 = Smin = minimum applied stress
R4 = K = stress concentration factor
R5 = FS = factor of safety

Instructions:

Enter the known values in each of the variables.  Enter the number of the variable to be solved in register I ( [ STO ] [ TAN ] (I) ).  To solve, enter a range, and press [ f ] [ ÷ ] (SOLVE), [ e^x ] (B). (*or whatever label you assigned this program to)

 Program:

Step
Key
Key Code
001
LBL B
42, 21, 12
002
STO (i)
44, 24
003
RCL 0
45, 0
004
RCL÷ 5
45, 10, 5
005
RCL 2
45, 2
006
RCL+ 3
45, 40, 3
007
2
2
008
÷
10
009
-
30
010
RCL 2
45, 2
011
RCL- 3
45, 30, 3
012
2
2
013
÷
10
014
RCL* 0
45, 20, 0
015
RCL÷ 1
45, 10, 1
016
RCL* 4
45, 20, 4
017
-
30
018
RTN
43, 32

Example:

Find the yield point (R0) given the following:
R1 = Se = 33,000 psi
R2 = Smax = 20,000 psi
R3 = Smin = 10,000 psi
R4 = K = 1.5
R5 = FS = 2
Store 0 in RI.

Solution:  55,000 psi



This blog is property of Edward Shore.  2016