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Time Dependent Hyperelastic Model
Posted Sep 30, 2011, 5:50 p.m. EDT Structural Mechanics Version 4.2a 2 Replies
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Hello,
I am using COMSOL 4.2 to model a Hyperelastic, 2D Axisymmetric body (Structural/Solid Mechanics) that is subjected to an axial prestressing load ,as well as, to a time dependent Harmonic Perturbation point load.
I am trying to solve my model for two study steps:
Step1: Stationary
Step2: Time Dependent
My goal is two see the effects of both prestressing and time dependent point loads on my model, but the problem is my solution does not converge.
I know that COMSOL has Preset Studies as:
"Prestressed Analysis, Frequency Domain"
and
"Time-Dependent Model"
but is there a way to have a "Prestressed Analysis, Time-Dependent" study that solves and considers both.
Thanks
Adam
I am using COMSOL 4.2 to model a Hyperelastic, 2D Axisymmetric body (Structural/Solid Mechanics) that is subjected to an axial prestressing load ,as well as, to a time dependent Harmonic Perturbation point load.
I am trying to solve my model for two study steps:
Step1: Stationary
Step2: Time Dependent
My goal is two see the effects of both prestressing and time dependent point loads on my model, but the problem is my solution does not converge.
I know that COMSOL has Preset Studies as:
"Prestressed Analysis, Frequency Domain"
and
"Time-Dependent Model"
but is there a way to have a "Prestressed Analysis, Time-Dependent" study that solves and considers both.
Thanks
Adam
2 Replies Last Post Aug 12, 2012, 1:14 p.m. EDT
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Posted:
1 decade ago
You can perform a stationary analysis and then use the solution as an initial condition for a transient time-dependent analysis. However, if the time dependent load is harmonic, why not do that analysis in the frequency domain and use the COMSOL preset study?
Nagi Elabbasi
Veryst Engineering
Nagi Elabbasi
Veryst Engineering
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Posted:
1 decade ago
Hi Sir,
I have a question that is sort of related to the one in this thread. For a cantilever that I am modeling that is subject to a constant DC current causing Joule Heating, I would like to determine the transient behavior. This means I want to see how the current, and with that the temperature and stress in the material, developes over time under influence of this voltage. Attached you can find my model.
When running the time dependent study however I get the message that the solver cannot evaluate the ec.DY (electrical displacement field in Y direction) variable. This is probably because no variable has been indicated to depend on time. I have indicated a time range in the "time-dependent" study step. I don't think doing a stationary analysis, storing the results and then doing a time-dependent analysis will fully reveal the transient response I'm looking for in this case.
Is there such an option for a DC voltage to be applied at time 0 and see how the joule heating effects (and with that the stresses) evolve? Or do I have to make up a function that indicates how the voltage behaves in time? In that case I could mimic the DC voltage by an AC voltage with a very long period and small offset from the bias voltage, such that it remains almost equal to the DC value over the short time (max 5 sec) observed.
Something like 5+0.0001*sin(0.000001*2*pi*t).
Do you think this is a good idea or do you know of a more elegant way to accomplish this?
Your help is well appreciated.
Thanks in advance.
Regards, Arjan
I have a question that is sort of related to the one in this thread. For a cantilever that I am modeling that is subject to a constant DC current causing Joule Heating, I would like to determine the transient behavior. This means I want to see how the current, and with that the temperature and stress in the material, developes over time under influence of this voltage. Attached you can find my model.
When running the time dependent study however I get the message that the solver cannot evaluate the ec.DY (electrical displacement field in Y direction) variable. This is probably because no variable has been indicated to depend on time. I have indicated a time range in the "time-dependent" study step. I don't think doing a stationary analysis, storing the results and then doing a time-dependent analysis will fully reveal the transient response I'm looking for in this case.
Is there such an option for a DC voltage to be applied at time 0 and see how the joule heating effects (and with that the stresses) evolve? Or do I have to make up a function that indicates how the voltage behaves in time? In that case I could mimic the DC voltage by an AC voltage with a very long period and small offset from the bias voltage, such that it remains almost equal to the DC value over the short time (max 5 sec) observed.
Something like 5+0.0001*sin(0.000001*2*pi*t).
Do you think this is a good idea or do you know of a more elegant way to accomplish this?
Your help is well appreciated.
Thanks in advance.
Regards, Arjan
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