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geirove
New member
Username: geirove

Post Number: 1
Registered: 04-2010
Posted on Tuesday, April 06, 2010 - 04:15 pm:   

Hello,

I have attached a simple model of a Beam with an internal Heat source. I want to compute the Max Temperature (and the Time for this max) for the X-axis accross the Top Surface of this Beam: Actually along the very axis as one of my History Plots.

I want the time, since this is the time I want to do the plots for. I have made som crude attempts to compute this time along the top of the Surface with no luck.

Actually, "history(Tpc) at (0, thick/2)" has the Temperature values, but I find no ways to get the Max Temp and its associated Time?

Is there a simple way to do this?

Geir Ove
Norway
application/octet-stream2D Beam with Internal Heat Source
GOS_FlexPDE_2D_Beam_02_Modified.pde (2.7 k)
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rgnelson
Moderator
Username: rgnelson

Post Number: 1343
Registered: 06-2003
Posted on Wednesday, April 07, 2010 - 08:36 pm:   

You can use GLOBAL VARIABLES to track maxima and minima as shown in the attached script (though this seems to lag the true time by one timestep).

The built-in function TIME_MAX(expression) stores the temporal maximum value of the given scalar expression. We neglected to implement a function to retrieve the time at which this maximum occurred. We wil add this in the next maintenance release. You can still get an approximate value as in the attached script.

VARIABLES are computed as fields on the entire domain, so they have a different value at each mesh node.

Passive() hides the argument from differentiation in computing slopes for the Newton's method, and is useful only when nonlinear terms are pathological.

Plot times are expanded as a list of fixed numbers at the time the script is read. There is no mechanism for dynamic selection of plot times.
application/octet-stream
GOS_tempmax.pde (3.1 k)
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geirove
New member
Username: geirove

Post Number: 2
Registered: 04-2010
Posted on Thursday, April 08, 2010 - 10:40 am:   

Hello Nelson,

Thank your for your fast response. However, the your solution gives the global maximium of Tpc, which is not what I was looking for. As I tried to state in the posting above and in my code, I am looking for the max along the axis "(0, thick/2)" as in "history(Tpc) at (0, thick/2)" and its associated time value.

How do I do this?

Geir Ove
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rgnelson
Moderator
Username: rgnelson

Post Number: 1344
Registered: 06-2003
Posted on Thursday, April 08, 2010 - 01:53 pm:   

Use VAL(Tpc, 0, thick/2) in place of the Globalmax.

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