Ασ σ σ – HP 50g Graphing Calculator User Manual

Page 222

Page 6-16

The equation is

here e

is the unit

strain in the x-direction,

, and

, 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,

is the thermal

expansion coefficient of the material, and

T is a temperature increase.

Suppose that you are given the following data:

= 2500 psi,

=1200 psi,

and

= 500 psi, E = 1200000 psi, n = 0.15,

α = 0.00001/

ΔT = 60

To calculate the strain e

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

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:

)]

(

[

⋅

−