Flexible contact in MV 2022.3?

Brian_20847

Hi everyone,

I am running flexible contact between 2 gears, but I have these errors.

Please see this image to know this error and find this attached to know my model:

https://ftam1.altair.com/message/fhuQC39eJumRhvg5XiJpGo

Thanks.

Praful

Hello Brian - The solver integrator has difficulty at a certain time. Here are some observation/comments related to the flexbodies that may help resolve it. (not guaranteed but worth trying)

1. The gear meshes have a lot of penetration to begin with.

2. The flexbody mass looks suspicious with output gear at 0.0006 kgs ! The fem file shows having a MAT card with density 7.85e-9. I presume the mass unit used here is MEGAGRAMS. But while creating the flexbody the same may not have been used.

4. Try reducing the Minimum step size. But if you fix the penetration issue, this may not be required.

Once you have addressed the above,

Flex contacts need better modal accuracy around the region of contact. So, generally, it is recommended to solve it in 3 steps. 1) generate a loadset file using the current flexbodies. 2) Create new flexbodies using Craig Chang contact method and the loadset file generated in step 1. 3) Update the model with new flexbodies.

Refer to help on Flex contact

Good luck !

Praful

 

Brian_20847

Praful Prabhu_20784 said:

Hello Brian - The solver integrator has difficulty at a certain time. Here are some observation/comments related to the flexbodies that may help resolve it. (not guaranteed but worth trying)

1. The gear meshes have a lot of penetration to begin with.

2. The flexbody mass looks suspicious with output gear at 0.0006 kgs ! The fem file shows having a MAT card with density 7.85e-9. I presume the mass unit used here is MEGAGRAMS. But while creating the flexbody the same may not have been used.

4. Try reducing the Minimum step size. But if you fix the penetration issue, this may not be required.

Once you have addressed the above,

Flex contacts need better modal accuracy around the region of contact. So, generally, it is recommended to solve it in 3 steps. 1) generate a loadset file using the current flexbodies. 2) Create new flexbodies using Craig Chang contact method and the loadset file generated in step 1. 3) Update the model with new flexbodies.

Refer to help on Flex contact

Good luck !

Praful

 

Hi Praful,

I edited unit for flexible body, it can run but it has vibration.

I want to know it is due to penetration or interface nodes cannot match with COG point?

Thanks

Praful

Brian_20847 said:

Hi Praful,

I edited unit for flexible body, it can run but it has vibration.

I want to know it is due to penetration or interface nodes cannot match with COG point?

Thanks

Hi Brian - from the video it is hard to determine.

It could possibly be because of

a) the penetrations

b) contact properties-  you might need some tuning here.

regards

praful