| T O P I C R E V I E W |
| abhinav2031 |
Posted - 06/29/2011 : 08:31:29 AM
I have this equation called the Ree Eyring equation
E=e*exp((-U)/RT)*sinh(sigma*V/kT)
where E is the strain rate which is known for a set of data, e is the absolute reference strain rate which is to be calculated along with U and V which are the activation energy and activation volume respectively. The value of sigma(stress) is also known for data set at different temperature and different strain rates.
Does there exist a way in origin by which I can calculate these values may be using user defined function but i have already tried that and I have not been able to reach to any conclusions.
Thanks |
| 1 L A T E S T R E P L I E S (Newest First) |
| Hideo Fujii |
Posted - 06/29/2011 : 11:20:06 AM
Hi abhinav2031,
I'm not sure you simply have a difficulty to construct a formula to calculate E with a given T value? Or, do you want to perform a parameter estimation for e, sigma, U and V on the datasets of the independent variable T and dependent variable E? Or something else?
If you want to simply calculate a function value, you can use the Set Column Value tool (See the Origin help at the following section: "Workbooks, Worksheets and Worksheet Columns" > "Simple Manipulation of Worksheet Datasets" > "Using Formulae to Set or Transform Worksheet Column Values")
If you want to do the parameter estimation, you can use Origin's NLFit tool for the non-linear curve fitting/regression using your own user-defined function. (See Origin tutorial: "Fitting" > "Fitting Complex function").
Maybe you can clarify further?
--Hideo Fujii
OriginLab
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