HP 50G, User Manual

Page: 222 / 887

Page 6-16
The equation is here e
xx
is the unit
strain in the x-direction,
σ
xx
,
σ
yy
, and
σ
zz
, are the normal stresses on the particle
in the directions of the x-, y-, and z-axes, E is Young’s modulus or modulus of
elasticity of the material, n is the Poisson ratio of the material,
α
is the thermal
expansion coefficient of the material, and
Δ
T is a temperature increase.
Suppose that you are given the following data:
σ
xx
= 2500 psi ,
σ
yy
=1200 psi,
and
σ
zz
= 500 psi, E = 1200000 psi, n = 0.15,
α
= 0.00001/
o
F,
Δ
T = 60
o
F.
To calculate the strain e
xx
use the following:
‚Ï
@@OK@@
Access numerical solver to solve equations
‚O
Access the equation writer to enter equation
At this point follow the instructions from Chapter 2 on how to use the Equation
Writer to build an equation. The equation to enter in the
Eq field should look
like this (notice that we use only one sub-index to refer to the variables, i.e., e
xx
is translated as ex , etc. -- this is done to save typing time):
Use the following shortcuts for special characters:
σ :
~‚s
α :
~‚a
Δ:
~‚c
and recall that lower-case letters are entered by using
~„
before the letter
key, thus, x is typed as
~„x
.
Press
`
to return to the solver screen. Enter the values proposed above into
the corresponding fields, so that the solver screen looks like this:
, )] ( [
1
T n
E
e
zz yy xx xx
Δ ⋅ + + ⋅ − =
α σ σ σ