How to release contact by applied force [Transient]

User1357

Hello,

i have problems with combining the gravity of the wheel carrier, two loads (tload 2 is a small amount load (2000N) that comes from the top and is supposed to be activated for the whole time, tload1 is a big load that is applied only for a short time (between 0.1 and 0.3s). The wheel carrier is supposed to be pushed by tload2 and the gravity against the plate, that is fixed at its position. And between the 6 seconds, tload1 should be applied additionally for the short amound of time, so that the wheel carriere bumps upwards a little bit. How can i create the contact between the wheel carrier and the plate while its pushed down, but as soon as the big load is applied, the contact is released? I have attached my file and i hope somebody can give me help.

Adriano A. Koga

hi,

 

if you're running a linear transient analysis, this is not possible.

In linear models, the contact status will be defined at the beginning of your simulation, based on its relative position and gap. Once it is defined as closed or open, it will remain like this until the end.

 

If you really need contact to be taken into account, then you would need to perform a NL Transient analysis in OptiStruct, but of course, the running time will increase a lot, as the NL iterations would be needed.

 

I hope this helps you.

User1357

Adriano A. Koga_21884 said:

hi,

 

if you're running a linear transient analysis, this is not possible.

In linear models, the contact status will be defined at the beginning of your simulation, based on its relative position and gap. Once it is defined as closed or open, it will remain like this until the end.

 

If you really need contact to be taken into account, then you would need to perform a NL Transient analysis in OptiStruct, but of course, the running time will increase a lot, as the NL iterations would be needed.

 

I hope this helps you.

Hello, thank you for your answer. 

 

Okay i try a NL Transient analysis. The Problem is that i cant connect the contact between the small plate and the wheel carrier. I want to push the whole carrier by the gravity against the rigid plate that is fixed with spc's. Additionally there is a load (about 2000N) that is applied on the upper bar in negative y-axis. Between the 6 seconds of the time step, one high load (about 10000N) is applied on the bottom of the rim of the wheel for only a short time in postive y-axis (about 0.2 seconds). This load is supposed to represent a hit for example by curb or a pothole. Therefore, the contact between the wheel and the plate has to be disconnected in the analysis. Do you have any clue how i can realise that in one analysis?

User1357

I created a nl-transient analysis. The contact between the plate and the wheel works. But i have problems with the gravity. Although i created the gravity with 9810mm/s^2 and N2=-1.0, gravity pushes the carrier in positive Y-Axis. But actually gravity should push the carrier in negative Y-Axis (against the plate). Could somebody have a look, i attached the file.