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field of maximum temperatures over all time steps

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Hello everybody,


how do I get the field of maximum temperatures over all time steps in a transient heat transfer simulation (Comsol 3.5)?

I am simulating a welding process using the heat transfer module. I can already visualize the geometry of the weld pool at any time of the process using the isosurface plot of the melting temperature. Nevertheless I am actually interested in knowing the final geometry of the weld seam, which is the sum of all points that have ever (= in any timestep) reached or exceeded melting temperature.

My best idea so far was to somehow calculate the "field of maximum temperatures over all time steps" and then again use the isosurface plot. However I couldn't find out how to get the maximum temperature at every point. Any suggestions how to do it? Is it possible at all?

In case you have another (perhaps more practical) idea how to get the geometry of the weld seam, please let me know as well.


Thanks for reading and for your help in advance!

Regards,
Johannes

1 Reply Last Post Sep 21, 2012, 6:48 a.m. EDT

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Posted: 1 decade ago Sep 21, 2012, 6:48 a.m. EDT
Hello, Johannes,

I have a simple proposal, which is only valid if at each point T has only, at most, one maximum.
The idea is to define another variable (say c), which grows if T grows, and stays stationary otherwise. At a certain point, if T is continuously growing, or it has only one maximum, c should take T maximum value. The technique should be modified if T had more than one maximum.
You could implement the idea by adding another PDE equation, with c as its dependent variable. The PDE is something like:

ct = Tt*(Tt > 0)

I haven't tryied, but perhaps it woud work if you add the condition T > c, thus the PDE could be:
ct = Tt*(Tt > 0)*(T > c)
This last condition assures that c must grow only when T is growing and T is greater than c.

Luck.


Jesus.
Hello, Johannes, I have a simple proposal, which is only valid if at each point T has only, at most, one maximum. The idea is to define another variable (say c), which grows if T grows, and stays stationary otherwise. At a certain point, if T is continuously growing, or it has only one maximum, c should take T maximum value. The technique should be modified if T had more than one maximum. You could implement the idea by adding another PDE equation, with c as its dependent variable. The PDE is something like: ct = Tt*(Tt > 0) I haven't tryied, but perhaps it woud work if you add the condition T > c, thus the PDE could be: ct = Tt*(Tt > 0)*(T > c) This last condition assures that c must grow only when T is growing and T is greater than c. Luck. Jesus.

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