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How to enter summation of a series ? I am trying to enter prony series(generalized maxwell model) in which there is summation of series for a viscoelastic model. SO if anyone can help me.
View ArticleProblem when using "Remesh Deformed Configuration"
Hi, I'm running into problems when using the "Remesh Deformed Configuration" on a solution data set that contains results from a simulation including "moving mesh" and "solid mechanics" physics. A new...
View ArticleSolve 2D Euler equations by using general PDE (g)
Hi everyone, I want to solve a 2D Euler equations using Comsol to save programming and debugging time. Here the Euler equation is used to describe gas expansion, thus it includes conservation of mass,...
View ArticleGlobal eqn. Help
Hi guys, I'm having some issues with a global equation, specifically with the initial value assignment. I have a global equation governing a prescribed mesh displacement (rotation). The equation...
View ArticleCurrent conservation issue when integrating charge density
I am working with an AC/DC, 3D, Stationary, Electric Currents model. I am currently studying charge density between deep brain stimulation electrodes of different surface areas and geometries. To...
View Articlesetting variable for stationary vs time-dependent study in same project
I have a component definition for an electrostatic potential constraint: Vgate = 100 * (1 - exp(-t/3e-9)) This ramps up the gate bias to 100 volts with a time constant of 3 nsec. However, I'd also like...
View ArticleNon-Local Modelling
Hello all, I just started using comsol, moving from ABAQUS. I was hoping to gain advice on how to procceed with non-local modelling. I would like to know if comsol can for every point compute an...
View ArticleHow to add inertial lift force and Dean force
Hi everybody, I m doing simulation for inertial focusing. I need to see the effect of inertial lift force and dean force on particle. I m just wanted to know where these forces can be defined. I tried...
View ArticleTIME to FREQUENCY FFT
Dear all, I am simulating pulse echo technique using ultrasound. I have my results in time domain. Now I need frequency spectrum of my time dependent study result. In study 1 "time dependent " time...
View ArticleSimulation fails when I add heat transfer physics
Good morning, I'm a student and I'm trying to model on Comsol an implantable fetal pacemaker (PM). I modeled the system with a corkskrew (helix) that represents the working electrode of the PM; then, I...
View ArticleNumber of degrees of freedom solved for: 0.
Hello all, When I try to use 4.0, I met with this problem when solving. Does anyone know how to fix this? I think it might be that I did not add the mesh to the solver, which is different from 3.5a....
View Articleschottky contact
Hello, I am trying to make Schottky contact with the help of ZnO/Pt in semiconductor module. During solving i am getting this error(segregated step, undefined value found, Details-Undefined value found...
View ArticleSchottky contact
Hi, I am sovling for schottky contact of ZnO/Pt in semiconductor module.During solving i am getting the error like Segragated step undefined value found Details-Undefined value found in the equation...
View ArticleUndefined value found in the equation residual vector.
I'm solving for lid driven cavity with stratified flow. My error message looks: Undefined value found. - Detail: Undefined value found in the equation residual vector. There are 3 degrees of freedom...
View ArticleVarying capacitance using electromechanics
Dear Comsol User, I am trying to find variation in capacitance between two plates with applied body load. I defined an air box around the plates. Now I'm trying with electromechanics physics for...
View ArticleSolidworks assembly imported into comsol - simulation difficulties
I am a student trying to improve my personal knowledge and skill with Comsol and I have run into a problem while trying to run simulation on an assembly that I've designed. I built the assembly (a...
View Articlehow to do half model analysis
Dear all, i am doing a simulation where no. of elements and nodes are very large. that is why time taken is very large. my restriction is i can't take larger time step as well as coarser mesh. so all i...
View ArticleOrdinary differential equation
I have to enter two ordinary differential equation for single variable "a" such that for 0<a<.5 first equation will be governed and for .5<a<1 second equation. How to enter it in comsol.
View Articlechirp signal as a prescribed displacement
Hi everyone Can anyone help me to add a prescribed displacement of a cantilever beam as a chirp signal ?. I'm using 2D structural mechanics (plate) physics and time dependent study. Thanks in advance...
View Articleunknown varibles
Hi all, When I using the free and porous media flow module, a strange variable automatically appeared in the segregated step settings, usually named comp1.fp.Pmfinl11, together with the velocity...
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