The Museum of HP Calculators


Composite Body: Neutral Axis and Moment of Inertia for the HP-32SII

This program is by Eric Lundgren and is used here by permission.

This program is supplied without representation or warranty of any kind. Eric Lundgren and The Museum of HP Calculators therefore assume no responsibility and shall have no liability, consequential or otherwise, of any kind arising from the use of this program material or any part thereof.

Overview

For a buildup of n rectangular sections (ibeam, c-channel, sandwich, etc.), this program computes the location of neutral axis (measured from bottom of section), and the moment of inertia.

NOTE: One can model two plates with open space between by assigning B=0, H=distance between for the section between the plates.

The program was written for the new hp33s, but has been tested on the 32sii and works. Should also work for most HPs supporting keystroke rpn programming, like the hp42s. Hope it is of some use!

Listing

LBL I  
123456789
RCL Z
X != Y ?
CLVARS
123456789
RCL Z
X != Y ?
INPUT N
123456789
STO Z
INPUT B
INPUT H
RCL H
2
/
RCL +T
RCL B
RCL * H
*
RCL +Q
STO Q
RCL B
RCL H
*
RCL +R
STO R
1
RCL +V
STO V
RCL Q
RCL / R
RCL - C
X^2
RCL *A
RCL + I 
STO I 
RCL T
RCL H
2
/
+
RCL Q
RCL / R
-
X^2
RCL *B
RCL *H
RCL H
3
Y^X
RCL *B
12
/
+
RCL + I 
STO I 
RCL Q
RCL / R
STO C
RCL B
RCL * H
RCL + A
STO A
RCL T
RCL +H
STO T
RCL V
RCL N
X>Y?
GTO I  
RCL C  **location of neutral axis**
RCL I  **value of composite Ix **
CLVARS
RTN

Checksums-
HP32sii: CK=576B 138.0
HP33s: CK=C3CC LN=321

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