TIME 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 ArticleNonlinear Dynamic Response of a Clamped-Clamped Euler-Bernoulli Beam
I am currently modelling the nonlinear time response of a clamped-clamped Euler-Bernoulli beam using the geometric nonlinearity tool in COMSOL. I intend on doing so for a wide frequency range in order...
View ArticleInitial Pressure - error
Hi everyone, I try to model the influence of a heated boundary on surrounding air in a 3-d model. When I try to set the initial pressure in the laminar flow to: -spf.rho*g_const*(0.05[m]-z) I always...
View ArticleDiluted species transport - singularity error
Hi, I am trying to model the drying of wood in a cylindrical drum with fixed wall temperature. I keep getting an error at around 1.7 seconds into my simulation. Can anybody help me solve this issues or...
View ArticleRelative tolerance vs Relative Error
Hi all, having read many relevant threads and also searched in the comsol manual , i still dont understand the difference (if there is indeed some) between relative error and relative tolerance. for...
View ArticleAC current simulation
Dear COMSOL community, I am kind of new to COMSOL and I am building a Lorentz force based MEMS sensor. Basically the current passing through an Aluminum wire on top of the cantilever will interact with...
View ArticleTime-Dependent initial solution violates specified initial conditions
I am trying to build a dye-washout model (using Reacting Flow in Porous Media physics to predict the time-dependent concentration of a dilute species). I'm able to run simulations for varying lengths...
View ArticleProblem on result when simulate varied force between two permmanent magnet...
Hi, Currently, I am working on a 3D model of two permanent magnet plates (I have attached model below, the permanent magnet plates have alternating polarity). One permanent magnet plate can move in the...
View ArticleImporting data in 3 dimensions to COMSOL
Hello everyone, I have a question about importing data into COMSOL which I would then like to impose on my model. I have an excel spreadsheet that contains Width(x) and Length(y) and then x*y amount of...
View ArticleElasticity matrix in solid mechanics eigenfrequencies
Dear all, I am trying to study the vibrational eigenfrequency of a silicon nanostructure. I have built the geometry and when I try to define the materials, I used single crystalline Si with anisotropic...
View ArticleHow to plot time-dependent temperature profile at a point
Hi all, I have 1 question over here, i have been using the SAR head tutorial (Provided by comsol tutorial) to do research for my school project and i have 1 problem over here which is, i cant seems to...
View ArticleHow do you plot error in COMSOL Multiphysics V5.2?
While doing the simulation in COMSOL Multiphysics V5.2, I found that there were errors being plotted (for my case, it was from Convergence plot 1 and 2 I think). I would like to get this graphs for my...
View ArticleWay to speed up stopping of simulation? / way to keep COMSOL from...
Hello dear colleagues, Currently I am working on a model for reversed combustion of biomass using an Equilibrium model based on Gibbs Free Energy for the gas reactions. I have made a connection with...
View ArticleConvergence problem with Bi-directionally coupled magnetostrictive model
Dear all, I am now working on implementing the magnetostrictive model on COMSOL, for which I encountered a converging problem and I'm looking for your help. The constitutive equations I am interested...
View ArticleMinimising a functional in COMSOL - Optimization
Hi all, I am trying to minimize a functional in COMSOl through the optimisation module. The functional depends on two functions E(x) and G(x) (and their derivatives up to second order) plus two...
View ArticleTime Dependent Study
Hello everybody, There's something about the time dependent studies in COMSOL that I'm not able to understand and I would like you to help me if possible. I am solving a heat transfer problem and, to...
View ArticleDisplacement due to point contact
Hi, I want to simulate how a planar surface is depressed by the weight of a overlaying sphere (gravity loading) in Structural Mechanics Module. Both sphere and planar surface are expected to be in...
View ArticleError increases with mesh density for trivial 1D model
Having had some problems, I reduced them down to a surprisingly minimal example: • 1D, single interval, Laplace equation. • Dirichlet BC on left end: fix it at "1.0". • (There is a zero-flux BC on the...
View Articleassemble external force vector rather than the residual vector by comsol
Hi all, In a simple linear elastic problem, a FE equation can be written as K*U=F, I would like to know if comsol can assemble and output this "F" vector? In the documentation, it seems that comsol can...
View ArticleIn Segregated Step 1: There was an error message from the linear solver. The...
Hi all, Why does this error happen and how do I solve it? This is the log file: ============================================================ Minimum element quality: 0.03333...
View Article