1 view (last 30 days)

Show older comments

I am trying to find the values of the constant elastic modulus (E1) and viscosity modulus (eta1) from the Kelvin creep recovery equation. The data points of strain and time needs to be exported from an excel file(given) and the value of constant stress is given as 6 nN.

The equation being used is: here sigma(0) is the constant stress(given) and epsilon is the variable strain(data points given)

Star Strider
on 3 Aug 2021

@NDC —

To estimate the initial parameters for this, since is known, the asymptote as will be , and that gives a way to estimate E. Here, is essentially a time constant, so if you can calculate the time at 0.6 times the asymptote (use interp1), you can estimate the initial value of η as well, having already calcualted E.

Use those as initial values with the code you already wrote.

.

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!