There is an example in the "Abaqus Example Problems Guide" which features Fluid Exchange. It is 3.3.2 Side curtain airbag impactor test. You can take the input file and see how it works, try reimporting into CAE, etc.

Best regards,

David

Dear David,

Thank you for the advice but I already looked at this example. The problem is that the input file is rather complex and Abaqus CAE is unable to decrypt the fluid functionality from the INP file (fluid exchange for instance).

The ideal thing I am looking for is a simple example for fluid exchange functionality or something I can analyse in Abaqus CAE.

Best Regards,

Hi Antoine,

I have been trying to run a simple fluid exchange problem with two cavities but have been running into errors consistently.

I recently came across this error, "The fluid cavity with reference node number 2 has a negative mass. Check whether the fluid exchanges are correct. More than one fluid cavity may have negative mass. You can check the value by requesting the history output of the mass."

I haven't found much information about this interaction on forums. Please have a look at the attached file and let me know if you can figure out what the issue is. I also request you to please share any useful information that you might have.

Thanks,

Vinay

Hi Vinay,

I opened your .inp file. The simulation seems to start when you switch your Interaction Property/Fluid Exchange from Bulk Viscosity to Volume flux or Volume rate leakage. My guess is that Bulk Viscosity may need additional parameters relative to viscosity and mass.

I hope this will help.

BR,

Thank you, Antoine. That definitely helped.

I am currently trying to measure the compliance of the cavities which i had described previously. I have defined a fluid cavity interaction for the respective cavity. I apply uniform pressure on the walls of the cavity and I am using CVOL to track the deformation of the cavity. This method is not working for some reason. I have a feeling it has something to do with the ambient pressure parameter to be defined in fluid cavity definition.

I question is, the ambient pressure definition is the initial pressure of that cavity of the pressure of region surrounding that cavity?

If it is initial pressure of the cavity, then how can I set the ambient pressure for the whole model?

I am including an input file for the analysis for reference.

Thank you.

units are - mm, MPa, tonne/mm^3 etc

I will take a look at your .inp but be aware that some parameters cannot be imported from inp files, especially those dealing with fluid cavity.

You can use a predefined field on the cavity reference point to get an initial pressure. So far I never used ambient pressure in my models and I've found no significative differences with or without.

Regards,