Learning Forum

[zjuv9021]

Hi all,

I'm new to explicit, and am running in to some issues in getting my problem set up. To illustrate, I am trying to rotate a tube 30 degrees, and then displace it through that tube before it meets a constraint above it and double buckles on the compression side:

For starters, is ANSYS Explicit Dynamics = LS-Dyna? The reason I'm transferring over to explicit is due to the non-linear hyperelastic contact that is going on between the involved 4 layers. One issue that's different than in static structural I'm not quite sure if I'm doing right is the contacts:

 

I generally just had to input the friction coefficient... I don't know how/what the dynamic coefficient or decay constant is for these materials... How can I resolve this?

Additionally, I'm not quite sure if using Body Interactions is the same as contact and if so, how would I set it up for my problem?

 

I want to pressurize the tube to 1 psi, rotate it 30 degrees, and then subsequently push or displace it 0.2 inches. This (I believe) would be quasi-static and I do not care about velocities here, only the mechanism of failure (buckling).

Issues: I am not confident in my contact/body interactions re: dynamic coefficient/decay constant. I am also not quite sure how to determine the time step... if it's too small (e.g. 1e-05 s), it seems to "whip" my material as it rotates to 30 degrees and destroy it (erosion)... I would realistically expect a 1-2 second time frame for this to unfold... What is best approach here? Any assistance on how to get the correct physical behavior here without elements eroding off would be greatly appreciated.

Regards,

Zach

 

[Sandeep Medikonda]

Explicit Dynamics is different from WB LS-DYNA, they are 2 different solvers. Read here. 

Regular contacts are similar to mechanical but with body interaction you are defining automatic contact, i.e, contact behavior between all bodies that come within a proximity during the analysis will be automatically be accounted for. You can read about contact and in general how an explicit simulations work in the manual.

Regards,
Sandeep