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