Hello all,
I hope someone can help me with this. I am working with a Trios rheometer and have tried every procedure to try and get shear stress on the x-axis. It will only let me graph oscillation stress and stress, but I cannot get shear stress. I'm not too sure if it is even an option. Do I have to calculate it using other variables from my my csv file and then graph in MATLAB, if os what variable and equations would I need? Or am I doing the incorrect experiment (oscillation frequency, oscillation amplitude)? Please let me know if you can help!! I attached a picture of the graph I'm looking for.
I am not sure that I understand what you mean with ‘graph oscillation stress’ and ‘stress’, so my first advice would be to contact the instrument supplier. Because all parameters in dynamic mechanical rheology are time-dependent in a sigmoidal fashion, the quantity you really want to know is not exactly shear stress but rather shear stress amplitude [tau zero].
If the option of plotting versus [tau zero] is lacking, try to plot versus strain amplitude = [gamma zero] and apply a relationship from fundamental rheology:
[tau zero] = G* [gamma zero] = [gamma zero] [G’ exp 2 + G” exp 2] exp (1/2)
G* is complex dynamic shear modulus.
Sorry! I wrote 'sigmoidal' where 'sinusoidal' was meant. Furthermore you can check whether calculated [tau zero] is identical to the 'stress' variable in the Trios software.
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