I have a table of loads applied, and changes in length. I'm wondering if there is an easier way to define the proportional limit other than graphing it out.

dam u guys r ahead of me, we not up to there yet lol

you should plot it to see where it stops being linear
it's more visual than calculation based

If I were to plot it in Excel, are there any functions I can use?

you would simply ask excel to do a connected scatter plot
then just look to see where the linear portion ends.
it should be fairly easy to tell where it is at as long as your data is legitmate

This post was edited by saber_x3 on Feb 5 2014 12:19pm

I am really hoping my professor lets me submit work through Excel. I don't want to go through all this data by hand. Two separate problems, with about 40 data points in each.

from experience, that is kinda expected
you can easily get line of best fit for E and zoom in on that area