HP 50g Graphing Calculator - Manual (Page 754)

Page 22-39
necessary to plot the circle. It is suggest that we re-order the variables in the
sub-directory, so that the programs
@MOHRC and @PRNST are the two first variables
in the soft-menu key labels. This can be accomplished by creating the list {
MOHRCIRCL PRNST } using: J„ä
@MOHRC @PRNST `
And then, ordering the list by using: „° @)@MEM@@ @)@DIR@@ @ORDER.
After this call to the function ORDER is performed, press J. You will now see
that we have the programs MOHRCIRCL and PRNST being the first two
variables in the menu, as we expected.
A second example of Mohr’s circle calculations
Determine the principal stresses for the stress state defined by σ
xx
= 12.5 kPa,
σ
yy
= -6.25 kPa, and τ
xy
= - 5.0 kPa. Draw Mohr’s circle, and determine from
the figure the values of σ’
xx
, σ’
yy
, and τ’
xy
if the angle φ = 35
o
.
To determine the principal stresses use the program @PRNST, as follows:
J
@PRNST Start program PRNST
12.5˜ Enter σx = 12.5
6.25\˜ Enter σy = -6.25
5\` Enter τxy = -5, and finish data entry.
The result is:
To draw Mohr’s circle, use the program @MOHRC, as follows:
J
@MOHRC Start program PRNST
12.5˜ Enter σx = 12.5
6.25\˜ Enter σy = -6.25
5\` Enter τxy = -5, and finish data entry.
The result is: