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Study inside Study
Posted 28 mag 2025, 21:36 GMT-4 Electromagnetics, Studies & Solvers, Modeling Workflow Version 6.3 2 Replies
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Hi everyone, I need some help with a multiphysics simulation in COMSOL. I'm working on a model that involves two main studies:
-A time-dependent study, where certain material properties (permittivity and conductivity) evolve over time according to a time-dependent variable.
-A frequency domain study, where I want to evaluate the capacitance of the system based on the state of the material at each time step from the time-dependent study.
My goal is to: Run a time-dependent simulation (e.g., from 0 to 6000 hours, with 1000-hour intervals). At each time step, perform a frequency-domain analysis (using a fixed excitation frequency). Extract the capacitance at a specific point in the excitation cycle (e.g., the peak of a square wave).
However, I'm running into issues: The material properties used in the frequency domain study seem to stay fixed rather than update based on the time-dependent solution. As a result, the capacitance result doesn’t change between time steps. I tried using the “Values of variables not solved for” field to specify the correct times, but I get errors like "parameter mismatch" or the solver just doesn't progress.
My question: How can I configure COMSOL so that the frequency domain study is evaluated at each time step of the time-dependent study, using the updated material properties from that time?
Thanks in advance for any tips!
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Hi Diogo,
Your project sounds like you were using time just as a parameter and there is no really time dependent physics. If this is the case you can just run a frequency domain study and add an auxiliary parametric sweep to it.
Cheers Edgar
-------------------Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
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Your project sounds like you were using time just as a parameter and there is no really time dependent physics. If this is the case you can just run a frequency domain study and add an auxiliary parametric sweep to it.
Edgar J. Kaiser, thank you very much for your reply. In my case, I’m analyzing the evolution of certain properties over time. To do this, I need to use the Solid Mechanics and Coefficient Form PDE physics to compute intermediate results, which I then use to calculate the electrical conductivity and permittivity. I already tried running everything in a single Frequency Domain study, but the issue is that the equations from the other physics interfaces (e.g., mechanics) start to incorporate the frequency as a parameter, which is not physically meaningful in that context. It is possible to keep the equations only in time dependent? Ideally, the frequency-dependent behavior should be considered only in the final study step, which I use specifically to evaluate capacitance.