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Piecewise function
Posted 25.05.2012, 12:37 GMT-4 4 Replies
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Hello,
I'm trying to define Youngs Modulus of a Material as a Piecewise function of Temperature.
Here is what I want to have:
for 273<T<473 E = E0
for 473 < T < inf E = kx + b
I'm trying to define Variables first, E for example, but the programs keeps making this variable orange.
How do I define a piecewise function, how does it work?
Thx in advance.
I'm trying to define Youngs Modulus of a Material as a Piecewise function of Temperature.
Here is what I want to have:
for 273<T<473 E = E0
for 473 < T < inf E = kx + b
I'm trying to define Variables first, E for example, but the programs keeps making this variable orange.
How do I define a piecewise function, how does it work?
Thx in advance.
4 Replies Last Post 26.05.2012, 06:26 GMT-4
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Posted:
1 decade ago
Hi
orange means unit (errors or misunderstandings) but are only warnings, you can still calculate and get good results if your values make sens, it's only that COMSOL cannot check the unit coherence, hence cannot adapt anything if not compliant with the COMSOL default units
A RED cell is a typo and this will not solve/calculate
probybly you should write something like:
273<T[1/K]<473
E = k[Pa/m]*x + b[Pa]
--
Good luck
Ivar
orange means unit (errors or misunderstandings) but are only warnings, you can still calculate and get good results if your values make sens, it's only that COMSOL cannot check the unit coherence, hence cannot adapt anything if not compliant with the COMSOL default units
A RED cell is a typo and this will not solve/calculate
probybly you should write something like:
273<T[1/K]<473
E = k[Pa/m]*x + b[Pa]
--
Good luck
Ivar
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Posted:
1 decade ago
I've tryed it, but there are some errors still. I've attached a jpg file to show, how I've done it. the syntax is definitly wrong, but I dont rly know how to do it right. I would be grateful for a little hint!
Thx in Advance!
Thx in Advance!
Attachments:
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Posted:
1 decade ago
Hi
I believe its the T= and E= that are not accepted
check the doc and the model library for a model having one of these functions
normally its the min value (number or parameter equation to calculate it, then the same for the max value and finally the equation, including the T, if T is the argument, but no = the response comes in the function name so you call it from any GUI field entry
pw1(T[1/K])
--
Good luck
Ivar
I believe its the T= and E= that are not accepted
check the doc and the model library for a model having one of these functions
normally its the min value (number or parameter equation to calculate it, then the same for the max value and finally the equation, including the T, if T is the argument, but no = the response comes in the function name so you call it from any GUI field entry
pw1(T[1/K])
--
Good luck
Ivar
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Posted:
1 decade ago
Thank you Ivar, that really helped!