HP (Hewlett-Packard) 50g ユーザーズマニュアル

Page 22-38

information tell us is that somewhere between 

φ

 = 58

o

 and 

φ

 = 59

o

, the shear 

stress, 

τ’

xy

, becomes zero.  

To find the actual value of 

φn, press $.  Then type the list corresponding to 

the values {

σx σy τxy}, for this case, it will be  

{ 25  75  50 } [ENTER]

Then, press 

@CC&r.  The last result in the output, 58.2825255885

o

, is the actual 

value of 

φn.

The procedure followed above to calculate 

φn, can be programmed as follows:

Program PRNST:
«

Start program PRNST (PRiNcipal STresses)

INDAT

Enter data as in program  MOHRCIRC

CC&r

Calculate 

σc, r, and fn, as in MOHRCIRC

“

φn” TAG

Tag angle for principal stresses

3 ROLLD

Move tagged angle to level 3

R

C DUP

Convert 

σc and r to (σc, r), duplicate

C

R + “σPx” TAG

Calculate principal stress 

σPx, tag it

SWAP C

R - “σPy” TAG

Swap,calculate stress 

σPy, tag it.

»

End program PRNST

To run the program use:
J

@PRNST

Start program PRNST

25˜

Enter 

σx = 25

75˜

Enter 

σy = 75

50`

Enter 

τxy = 50, and finish data entry.

The result is:

Running the program MOHRCIRCL for the first time produced a couple of new 
variables, PPAR and EQ.  These are the Plot PARameter and EQuation variables