Kinetic Friction, USB Connector (and learning Adv Simulation)

[JShuster81]

Hello,

I am currently trying to learn UG/NX Advanced Simulation package on my own using the manual, forums, posted examples, and trial and error.

I am currently looking at a USB connection (see attached Photobucket URL for pic of model). What I am trying to do is hold the spring hook contact fixed at one end and slide the straight contract over top of the hook contact in a horizontal fashion. So, basically, both terminals start apart, and then I move the horizontal terminal such that it contacts, slides over, and deflects the hook terminal. Is this even possible? I tried setting up the model and running it, but I keep receiving an error. My goal is to measure the force it takes to slide the two pieces over top of one another. It seems that NX/UG doesn't have a model for this type of contact. Everything I see involves static friction only, where the surfaces are very close to one another.

Also, can anyone point me to a website or some information that describes the capabilities and in-capabilities of UG/NX Forum.

My ultimate goal is to compare and contrast UG/NX Advanced Simulation and Abaqus FEA and see what kinds of models UG/NX can handle. I currently work with a lot of plastics. I model a lot of parts that require sliding friction models, parts that experience great plasticity, and models that require contact.

Any help or suggestions would be greatly appreciated.

 

[JHTH]

I think the problem you're describing is a dynamic one, rather than static, so the licences you've bought will determine whether you can do it or not; it won't be technology-limited.

That said, you could simulate it with a static solver by applying a known displacement to the flexible part and solve for the force required and then do an F = mu * R type calculation to find the friction force.

In summary, there's more than one way to skin a cat.

Cheers.

JHTH
NX 7.0.1.7 + TC 2007

 

[mlamping]

Your model should solve with a little guidance. This is a fairly simple problem for NX Nastran advanced nonlinear if you use enforced displacements to drive the motion. A linear ramp displacement over time will satisfy the motion requirement.

The attached file is a workshop created for internal training at Siemens PLM in 2006 using NX 4 and NX Nastran 4 advanced nonlinear. The model is very similar to yours... a plug being pushed into a socket.

While the workshop doesn't address your request for friction force values during the assembly/mating process, that can be obtained through an evaluation of the reaction forces that exist on the plug in the direction of the enforced motion. In fact an RBE2 is used to connect to the plug and the enforced motion is defined at a single node. So the reaction force at that node is the force required to push the plug in the socket.

The workshop may have a couple warts. Internal training documents aren't always scrubbed for accuracy since they aren't delivered with our customer facing training material. It's also a bit dated... 2006 so there will be differences in the UI in the document compared to newer versions.

Regards,
Mark

Mark Lamping
CAE Technical Consultant
Siemens PLM Software