A dynamic case for stressedFoam

fw407 · July 26, 2008, 18:47

Hi everyone,

I want to test the dynamic response of "stressedFoam". the test case is very simple:

"a 2D beam is fixed at the left end, and the right end is suddenly applied with vertical force F."

I have tried the boundary conditions named"constanTraction" which applies the sudden load at the specfied time, but it doesn't work(maybe I did not use it correctly, but so far, I haven't figure out why). did anyone do this before? Any hints are welcome.

Kind regards

feng

mathieu · July 27, 2008, 00:20

Hi !

You should use the tractionDisplacement BC for this with an initial displacement field set to zero. Note that the vibration may damp since the time scheme for d2dt2(U) can only be Euler (first order) which produce diffusion. A small time step may help with that issue.

Mathieu

fw407 · July 27, 2008, 08:00

Hi Mathieu,

Many thanks for your help!

In fact, I have done what you said, and got the curve for the dynamic response, but it quickly converge to the steady state solution. I will try reducing the time step to see whether it works for me.

Kind regards

feng

July 26, 2008, 18:47	Hi everyone, I want to test	#1
fw407 Member feng wang Join Date: Mar 2009 Posts: 67 Rep Power: 17	Hi everyone, I want to test the dynamic response of "stressedFoam". the test case is very simple: "a 2D beam is fixed at the left end, and the right end is suddenly applied with vertical force F." I have tried the boundary conditions named"constanTraction" which applies the sudden load at the specfied time, but it doesn't work(maybe I did not use it correctly, but so far, I haven't figure out why). did anyone do this before? Any hints are welcome. Kind regards feng

July 27, 2008, 00:20	Hi ! You should use the tra	#2
mathieu Member Mathieu Olivier Join Date: Mar 2009 Location: Quebec City, Canada Posts: 77 Rep Power: 17	Hi ! You should use the tractionDisplacement BC for this with an initial displacement field set to zero. Note that the vibration may damp since the time scheme for d2dt2(U) can only be Euler (first order) which produce diffusion. A small time step may help with that issue. Mathieu

July 27, 2008, 08:00	Hi Mathieu, Many thanks for	#3
fw407 Member feng wang Join Date: Mar 2009 Posts: 67 Rep Power: 17	Hi Mathieu, Many thanks for your help! In fact, I have done what you said, and got the curve for the dynamic response, but it quickly converge to the steady state solution. I will try reducing the time step to see whether it works for me. Kind regards feng

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