- #1
lanew
- 13
- 0
Homework Statement
http://img683.imageshack.us/img683/7060/selection001l.png
Homework Equations
[itex]\epsilon^{pl} = \epsilon - \epsilon^{el}[/itex]
[itex]\epsilon^{pl} = \epsilon - \frac{\bar{\sigma}}{E}[/itex]
[itex]r = \frac{\epsilon_w}{\epsilon_t}[/itex]
The Attempt at a Solution
I'm stuck trying to calculate [itex]\bar{\sigma}[/itex]. Can I just assume that [itex]\bar{\sigma} = \sigma[/itex] @ 104 s-1? If so, the axial plastic strain is calculated as follows:
[itex]\begin{align}
\epsilon_a^{pl} &= \epsilon_a - \frac{\bar{\sigma}}{E} \\
&= (0.10) - \frac{(66.1)}{(200*10^3)} \\
&= 0.09967
\end{align}[/itex]
and
[itex]\begin{align}
\epsilon_w^{pl} &= \epsilon_w - \frac{\bar{\sigma}}{E} \\
&= (-0.042) - \frac{(66.1)}{(200*10^3)} \\
&= -0.04233
\end{align}[/itex]
If this is correct I should be able to related the thickness by [itex]v[/itex], correct?
Also, as far as (b) goes, should I be using [itex]\sigma = k \epsilon^n \dot{\epsilon}^m[/itex]?
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