Latch modelling

[zerodof]

Hi, I am looking at the modes of the automotive closures in installed conditions using FE model. The latch stiffness is critical. Has anybody got any stiffness numbers(spring rates) for a fore aft,vertical and lateral stiffness taht can be used in the analysis.

Has anybody got any idea of range of frequency of the closures that one might expect closures.

Other ideas welcom

 

[GregLocock]

I suggest you contact your noise and vibration people. If the number is critical then taking someone else's WAG won't help much.

2000-5000 N/mm and 0-250 Hz would be my WAG

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[MikeHalloran]

You have the geometry and materials specs of the closure parts, right? Couldn't you figure out spring rates from that, even without FEA?



Mike Halloran
NOT speaking for
DeAngelo Marine Exhaust Inc.
Ft. Lauderdale, FL, USA

 

[zerodof]

The latches are very non linear and difficult to model. The tailgate modes are senstive to latch stiffnesses and these modes flare the torsional body modes.

 

[GregLocock]

Well, given the enormous diferences in detail design between different models and manufacturers, it seems unlikely that an untuned plug number will work. You could wander along to your local friendly non linear multibody dynamics guy, and ask him to model it.

His answer, oddly enough, will be to go to talk the modal analysis people. Without correlation data his model will be rubbish, as will yours.



Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.