Hello,
I am trying to model deformation caused by cooling in Aluminium rod with fixed boundary condition on either side. Its initial temperature is 300 K and final temperature is 10 mK. But i am not sure how to proceed. How should i put my initial and final condition ?
Dear all,
In COMSOL, can we set values of variables during time dependent simulation forcibly?
Nakamura
Is there a way to find the effect of heating and thermal expansion of a structure on the electrical properties? Can we plot Electrical Resistance vs Temperature Curve on COMSOL?
Hi Folks! I need a help please.
I am wondering which variable decribes the iteration number of optimization ? I am using MMA and I want to change some variables as the iteration number changes.
Thanks Xuan Wu
Dear all I was wondering if it would be possible to import the deformed mesh/geometry and an input file with the stress-strain data after a solid mechanics analysis made in ABAQUS to define an initial state in COMSOL in order to use that geometry and those stress-strain results in other COMSOL's modules. Can anybody help me? Any help is appreciated. Thanks in advance, Javier
Hi,
I'm using COMSOL 5.2 with the Structural Mechanics module to calculate eigenfrequencies and eigenmode shapes of a nanobeam design. I would like to export a 3D visualization of all the mode shapes that have been calculated, for example into a series of image files in a folder. I know how to export a 3D plot of every individual mode shape (by selecting an eigenfrequency and saving the corresponding mode shape), but I'm looking for an option that will allow a 'batch' export of all eigenmodes.
It feels like there should be a natural way for this, but I haven't been able to find it. Any help is greatly appreciated!
hi, I try to apply the example of (Transfer Impedance of a Perforate) on figure below. I drew the geometry but do not know how to apply the physisc.. if any one can help me...Thanks
Comsol v5.3a
I have a parametric sweep solution from two varied parameters (viscosity and inflow) for a stationary fluid simulation. When I generate my reports, it only generates the plots for the currently selected set of parameters on the referenced plot. How can I output all of my plots without having to manually change the parameters on each plot one by one? Making a separate report for each doesn't seem feasible since they would all reference the same plot... The only other workaround I can see is copying the plots each plot to the clipboard and into an external document, but this is extremely time-consuming as well. Is there something I'm missing?
Hi,
I am currently doing my PhD studies and I have a problem understanding the weak constraint/weak contribution in the Weak Form PDE toolbox. I'm trying to implement an RVE (Representative Volume Element) in 2D using Weak Form PDE. Everything worked great until I tried to implement a constraint equation.
The equation I need to implement as a constraint is in the following form:
vint(u*x) = 1
That is, I want to constraint the volume integral (in the whole domain) of u*x (where u is the displacement field in x-direction and x is just the nodal x-coordinates) to a constant value, here 1. I've tried using the Weak constraint node, but get singular matrix. The pointwise constraint works better, but the results are completely wrong (and give a great error).
Is there a way to implement such a constraint in Comsol, and how?
Thanks for any help!
Hello everyone,
I've been looking into this for a while, but can't figure out how to do the following.
I have a transdcuer in an air sphere with a PML and I want to calculate the pressure and the phase along a parametrized curve in the far-field. I can do this quite easily by manually creating a curve in the results and plotting the values and then doing some post-processing to the data. In my case I am interested in the variance along the curve in the far field.
However, I would like to be able to do this operation as part of the parametric sweep function. In my case I would like to plot the variance along a number of curves with slightly different coordinates.
Does anyone know how I might go about doing this?
Thanks very much,
Rob
Hello, I am trying to model PN junction in thermal equilibrium with the help of transported of dilute species and Electrostatics model, where I am trying to simulate the model for drift and diffusion, I am confused about the boundary condition for potential and space charge density can anyone could help me about it?
I am designing a microwave lumped element resonator which is contained in a metal box. My simulations consists of the resonator with PEC BCs simulating the metal of the resonator as well as the limits of the simulation box. My issue is that when I simulate the design with no loss (no material losses or scattering BCs) I get a divide by zero error related to emw.etaRef (not sure what this is anyway), but as soon as I include any loss (in my case I add a tiny patch of scattering BC in the simulation box) the eigenfrequency search goes without a hitch.
Any ideas concerning what's going on would be appreciated.
-Steven
Hello,
Let me preface this question by adding that I am a relatively novice user of COMSOL.
I am working on modelling a micron-scale device with both semiconductor and metal components. The goal is a simultanous electrical and thermal model. Hence, it is necessary (as far as I understand) to physically include actual metal contacts in the model--as opposed to using the "metal contact" boundary parameter in the semiconductor module.
For models without any semiconductor components, one can easily solve for thermal/electrical effects using the Heat Transfer in Solids and Electrical Currents/Electrostatics modules. However, the Semiconductor module appears to handle it's own electrical variables interally.
So, I am wondering: Is it possible to couple the Semiconductor and Electric Currents/Electrostatics modules in order to model a device with both semiconductor and metal components?
Thanks in advance, Ara
Hello all,
While using the reaction engineering module, I sometimes noticed that there were some discontinuity in the concentration over time plot that were generated from a converged solution. It seems that the discontinuity is due to the presence of the negative values. The curve shows the anticipated trend with the discontinuity. Do you know whether the curve is still acceptable?
Thank you, Woo-Jae
Hi, I'm new to Comsol and I'm working on a time dependent model. The temperature distribution along a wall is a function of temperature gradient and also something calculated based on result from previous step. My questions are: 1. Do I use Matlab code to define my boundary condition? How can I extract data of temperature gradient from result of previous step? 2. I need to use some code to calculate something every step. How can I do that in Comsol?
Before I come to Comsol, I tried Ansys Fluent, I can define user-defined-function on both boundary condition and 'Execute at end' section, do we have something like that in Comsol?
Any help will be so much appreciated. Thanks in advance.
Jing
the interface of magnetostrictive is defaultly mf module,could I replace it with mfnc module by changing the variable in it? because the mf module is too difficult to convergence. besides,could you tell me the difference the background magnetic field in mf module and mfnc module. thank you very much!
when I compute the COMSOL, it encounter a problem "Cannot create native file C:\Users\jong_.comsol\v53a\recoveries\MPHRecovery" .This problem for me is a new one, who can help me.
Hello!
I'm trying to solve a (quite simple) 2D-axissym. model of a fixed bed reactor. I have four species where only three a actually taking part in the exothermic reaction. The chemistry is modeled in re (reaction engineering module) and exported to the 2D-model where I use the following modules: tds (transport diluted species), ht (heat transfer in fluids) and br (Brinkmann-equations).
As far as I can see, I set up the model correctly. But when I want to solve it, it takes hours to assemble the matrix!!!
Is this a normal behaviour? Or where could I start finding the mistake?
Thanks in advance! Till
Hi everyone I am currently trying to simulate solar cell based on Semiconductor-Electromagnetic Waves Coupling . The main node that combines two physic modules is optical transition. However, i dont really understand how it re-calculates permittivity and susceptibility in coupled node. Please help me out if you have ever tried and done it. Thank you
Hi,
I am trying to simulate the ultrasound from a phased array into a material. The material is orthotropic/anisotropic. We know that speed of sound varies according to direction of propagation in anisotropic materials. But when I check here the speed of sound is constant. How do I vary the speed of sound wrt to the direction. I am using the solid mechanics physics for the whole simulation. This question might be a little stupid but any help would be highly appreciated
Thanks !