Undefined value found in the equation residual vector
hi,would you please help me about the problem i have met? I post a message on the website but got noting useful about it. The link is as following:cn.comsol.com/community/forums/general/thread/72611/...
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Hi, I am trying to model a capacitive force sensor in COMSOL using solid mechanics and electrostatics physics. The model consists of a nylon spring between 2 silicon capacitor plates that experience a...
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Hello, In my model, I have created two studies to be completed, each performing a different load on the object. I want to use the results of the load for the first study as the initial values for...
View ArticleDoes COMSOL support user-defined element like Abaqus does?
Hi all, Anyone knows if COMSOL support user-defined element like Abaqus does? I am now using eXtended finite element method(XFEM), in which, the elements cut by the interface are enriched, so there are...
View Articleoutputs from mphgetu and mphmatrix
Hello, I'm looking at a time-dependent 1D 'Coefficient Form PDE' problem. I mesh the line with 4 element (5 nodes). So I have 5 degrees of freedom, the relevant system matrices are also 5x5. Also to...
View ArticleGreat mechanical expansions
Hi everybody, I am trying to simulate with Structural Mechanics Module in 2D axial simmetry (COMSOL 3.5) the following situation: I would like to predict the stresses of a material under the loads...
View ArticleEquation in matrix form for use for MATLAB Livelink
Dear all, This seems to be a pretty simple question but I am struggling to find any help on the topic! I have recently started using COMSOL with the livelink to write a Model Order Reduction in MATLAB....
View ArticleHow can I fix it?
I use the transport of diluted species to solve a porous media problem but water contain steady inside without diffuse and the result shown in following error. What should I do? Undefined variable. -...
View ArticlePlot a graph along a line
Dear Sir, I am using joule heating module. I have a plot of temperature distribution along a microheater. Now i want to plot the variation of temperature along y=x or x= 10, 20 etc so for that i need a...
View ArticleUsing COMSOL for Meshing and Solving of Specific Element
Dear Colleagues, I am new to COMSOL and have very basic question. I am working of flow and stress in porous media. As part of my research, I will develop an element with specific degree of freedoms at...
View ArticleStationary Study and Time Dependent Study of Same Model Disagree
Hi, I'm running an electric currents interface for a dielectric board with a couple ground points and a constant current source within the dielectric. I'm interested in the transient solution to this...
View ArticleUpdate variable at the end of each timestep
Hello everyone, I was wondering if there is a solution for updating variable at the end of each timestep without using LiveLink for MATLAB. For example, if I want to modify the parameter A, at the end...
View ArticleTransferring Parametric Sweep Solutions Between Studies
Hello, Does anyone know if it's possible to transfer solutions from one study using a parametric sweep to another study using an identical parametric sweep? For example, I would like to use a...
View ArticleNavier stokes in COMSOL
Hello everyone, I am trying to find out how the compressible NS equations are solved in COMSOL. There are ample explanations of how this is achieved in fluent. Some of the things I am interested in...
View ArticleCOMSOL, system of first order ODEs, boundary value problem
I have five equations, 4 of them are first order ODEs and the last one is an algebraic equations. I am trying to solve this set of equations in COMSOL and I have four boundary conditions two on each...
View ArticleERROR - MESH SIZE
Good night, I am having an error starting a simulation of piezoacoustic model of a sonar with a mesh size of water domain for maximum analysis frequency of 100 kHz :"Failed to find a solution for the...
View ArticleCOMSOL for an element developed in MATLAB
Hi everyone, What is the best way of using COMSOL as solver and for preprocessor (creating the model and meshing) for an element developed in MATLAB? Is it even possible to have a user-defined element...
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