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Having trouble about importing 3D geometry

March 13, 2015, 5:42 am
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When I am trying to import a 3D geometry file named XX.SLDPRT(a Solidworks file) or XX.ipt(Inventor file), it turns out to show: D:\Program Files\COMSOL\COMSOL50\Multiphysics\lib\win64\csjcad.dll: Can't find dependent libraries. (attached file)
How should I do? There is no problem when I'm importing mphbin file.
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installation error

March 21, 2016, 2:13 am
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Hello, everyone

I am trying to install COMSOL 5.2 on my computer, and get an error dialog:

Failed to decomperss fl_jvm_win64.isa
see log file for detail:
C:\Users\ADMIN~1\AppData\Local\Temp\comsolsetup_setup_5676.log

the log file gives the following message:

Entering femlabSetupMain function.
Creating directory C:\Users\ADMINI~1\AppData\Local\Temp\comsolsetup5676
Creating directory C:\Users\ADMINI~1\AppData\Local\Temp\comsolsetup5676\bin
Creating directory C:\Users\ADMINI~1\AppData\Local\Temp\comsolsetup5676\bin\win64
Copying files from G: to C:\Users\ADMINI~1\AppData\Local\Temp\comsolsetup5676
Decompressing G:\archives\fl_jvm_win64.isa to C:\Users\ADMINI~1\AppData\Local\Temp\comsolsetup5676\fl_jvm_win64.tar
EXIT FAILURE: Failed to decompress fl_jvm_win64.isa.
Removing temporary setup dir C:\Users\ADMINI~1\AppData\Local\Temp\comsolsetup5676

It seems that the fl_jvm_win64.isa cannot be decompressed in the progress on my computer. But COMSOL 5.0 can be correctly installed. And V5.0 also contains the flie fl_jvm_win64.isa .
What is the problem? Can anyone help me？


--thanks, Chu
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Evaluating more than one expression in Global Evaluation?

May 10, 2016, 4:22 pm
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Hi

Is it possible to evaluate more than one expression in Global Evaluation, in one step?
My goal in this postprocessing step is to tabulate and plot a variable for different mesh sizes (i.e. from different data sets). My solution is time-dependent.

Currently what I am doing is using Derived Values/Global Evaluations through which I can get ( t , Data1(u) ) & ( t , Data2(u) ) separately and then combine the data. If I have numerous data sets, I have to calculate ( t , DataN(u) ) separately, which may not be time efficient. I tried the Join Date Set, but the problem with Join is twofold:

1- I prefer to extract the original values from my studies, rather than getting Difference, Sum, etc. that software makes available. Basically I want to tabulate ( t , Data1(u) , Data2(u) ), but apparently this cannot be done.
2- In join apparently we can compare two data sets, unless we Create several Joins and them combine them.


Thank you for checking this post.
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design of electrode

May 13, 2016, 3:33 am
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sir/madam ,
i m working on topic dielectric elstomer actuator how i apply voltage on electrode .
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Linearly polarised modes of fiber

May 13, 2016, 5:56 am
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can any tell how to get all Linearly polarised modes i.e LP52, LP62, LP72 etc. for multimode fiber..?
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potential of an trapezoidal cross section cantilever

May 13, 2016, 8:09 am
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sir i got some problem regarding potential and i didn't even get any voltage i got 0 v in every frequency.
i m working in frequancy domain. i have completed all the work but i could not stimulate and i got some problem in evaluation of voltage . i have some pics of this simulation plz help me .

thnx
sahrukh khan
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User defined subroutine

May 13, 2016, 12:04 pm
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Can we implement a subroutine into COMSOL as we do in Abaqus? Say we want to define a new type of element or shape function. Does COMSOL support this?
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Declaring Multiple Integral in Comsol

May 13, 2016, 12:17 pm
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Hi everyone,

I am wondering how multiple integral can be declared in Comsol ( expression in Fig2).

It will not be difficult to declare expression 'B' (Fig1) through Built-In "integral" Function or "Integration(intop1) " over a domain 1D.

Can anyone help me calculate expression in Fig.2 ?

Thanks a lot for any help !

Best regards,
N.N
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The relation between mesh size and time step in time-dependent study on heat transfer problem

May 13, 2016, 1:03 pm
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Dear all,

I am simulating heat transfer problem and when it comes to set up the mesh, is there a limit on the max mesh size according to the time step I set up? Say I compute the heat transfer and want to see the temperature distribution in the material each 1ms, is there a requirement for the mesh size due to this condition (or the velocity that heat travels)?

Thanks.
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Impose a limitation for solving an equation

May 13, 2016, 1:37 pm
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Hi,
I'm using general PDE in COMSOL. I want to solve the equation by this condition:
The calculated main variable in each time step can not decrease, in other words if A is the main variable, then dA/dt>0 (t is time) .

How can I impose this condition?

Thanks,
Arezoo

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Time study simulation

May 13, 2016, 2:05 pm
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Hi,
In time dependent study simulation in COMSOL, we need to define range in study setting as below:
range(time1, TIME, time2)
This means that the simulation will be study between time1 and time2, the time duration in each time step is adaptive but it can not bigger than TIME and in each TIME the results will be saved.
I need to decrease TIME because I want to put a restriction to max time step in my simulation not bigger than a particular value, but I don't want to save the results in all TIME steps to reduce the memory space.
how can I solve a study in particular time steps but save the results in some of that time steps?

Thanks
Arezoo
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Postprocessing and visualization

May 13, 2016, 5:14 pm
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How can I plot in a self-defined function instead a cut line within a 3D model?
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How to stop time-stepping at equilibrium state for time-dependent problem?

May 13, 2016, 5:45 pm
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Is it possible to use Stop-Condition to stop a time-dependent model that reached to equilibrium state? I'm trying to use the following expression with prev operator in Stop Condition node. But it is not working.

Does anyone know another way?

abs(comp1.M3_avr-prev(comp1.M3_avr,1))-Error Stop if Negative (<0)

M3_avr is my variable.
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User defined Coil Geometry- Square shape PM and Coil- Moving mesh

May 13, 2016, 8:48 pm
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I have modelled a square shape coil and square shape permanent magnet (PM).
In my model, square shape PM can move in z direction, but there is no motion for the coil.
My problem is with using the current flow in the coil as I am using user defined coil geometry for my model because I cannot use linear or circular type coil for the considered geometry of the coil.
I don't know how I can define coil current flow in user-defined coil geometry.
I run the model and for the time dependent part the obtained current is zero but it shouldn't be because there is a relative motion between coil and PM, and I think it is related to defining coil-current flow.
Please note initially the considered current for the coil is zero, but we must have induced current in the coil because of having relative motion between coil and PM, and accordingly, change of magnetic flux density.

It would be great to help me for it.

Thanks, Ehsan
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Connecting 2D polygons

May 13, 2016, 10:01 pm
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Hey I am importing points into comsol that form 2D polygons, that are asymmetrical and concentric to one another. I am wondering if there is a way that I can connect the 2D polygons to each other to form a 3D tube that is in their shape?
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What's wrong with Nickel Steel Supersquare 80?

May 13, 2016, 11:23 pm
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Hello everyone.

I just read the blog "Modeling Magnetostriction Using COMSOL" and downloaded the model "Nonlinear Magnetostrictive Actuator and Sensor".

I replaced the material "soft Iron" by "Nickel Steel Supersquare 80" and run the model again. Then error was shown.

Can anyone tell me why this material can not be used?

Thank you.
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Energy Harvester with Different Geometries and Cross Sections

May 2, 2016, 11:52 am
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hello sir

with all due respect i need some help regarding cross section in comsol multiphysics. i got some problem related to different geometries and cross sections . i tried harder to create trepezoidal form but i failed and didn't got as i want to get . so help to make through this and i have jpg of cross sections .

it's very important plz help me asap

thnx
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Use of global parameters in expressions

May 14, 2016, 8:16 am
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Hello,

I am using Comsol 4.2.

I have defined global parameters, such as L, H, W etc. And i have the global parameters ax = 5[m] and x0 = L/2-(N-1)/2*ax.

Also I have defined an analytical solution: V_ref = 1[A]*rho0/(2*pi)*(1/abs(x-x1)-1/abs(x-x2))
Arguments are x, x1 and x2

Then under Data sets i defined that the 1D function's argument x goes from 100 to 600.

Now I want to plat the function in a line Graph. The Expression is: abs(V_ref(x,x0+15*ax,x0+25*ax))
This expression can not be evaluated.

Error message:
Failed to evaluate variable.
- Variable x0
- Global scope:
Failed to evaluate expression.
- Expression: abs(V_ref(x,(x0+(15*ax)),(x0+(25*ax))))
Failed to evaluate expression.
- Expression: abs(V_ref(x,x0+15*ax,x0+25*ax))
- Plot: lngr1 (Line graph)

Can anyone help me? I do not see the problem that COMSOL has
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Problem in drawing distinguishing line between melted material and solid portion

May 14, 2016, 10:45 am
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Sir, I have done thermal problem with comsol. the results are OK. but in the post processing section I want to draw a distinguishing line between melted material and the solid portion. In short I want to draw a constant temp line. how to do it. please help.
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Polygon to Solid conversion

May 14, 2016, 1:44 pm
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Hi all,

I am trying to convert a polygon I created into a solid, but I keep receiving an error saying that output object is empty and I do not know what that means?
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