Cosmos & Coat Hangers

Greets all. Am looking for a few pointers to get a CosmosWorks(2004) static analysis working. This is purely a learning exercise for me and any tips would be greatly appreciated -- hope I'm asking this in the right place.

I've modeled a (plastic) coat hanger -- looks like a number "2" in profile. I've added it to an assembly with a cylindrical "stub" to represent the piece of tubing that its hanging on. The inside "hook" of the hanger is mated (tangent) to the cylindrical face of the pipe. The assembly dynamics work correctly in that i can "pull" the hanger around the pipe and it maintains tangency on the inside without "falling off" (there is a coincident mate with a plane of the pipe).

In short, two-piece assembly (coat hanger + pipe stub). Pipe stub is fixed, Hanger is completely mated and floating.

In CosmosWorks, the pipe stub is Fixed. There is a 1kg load on the hanger -- top face of the "lower leg" -- where a pair of pants, say, would contact the surface once hung.

I'm having trouble mating the contact surfaces. (I think)

During simulation the hanger rotates around the pipe and the analysis fails.

Setting a Fixed restraint on the small circular face that is the "tip" of the hook solves the problem but results in an unacceptable analysis. (Ie, real hangers aren't fixed there, and i see no stresses at the contact point.. only in the throat of the hook). I expect to see the hook to stretch and the bottom leg to "droop"

Sorry so long-winded. My question boils down to: how would you set analysis up? Again, any pointers would be greatly appreciated.

-Tony

ps. LargeDeformation Contact is checked and am using FFEPlus solver

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"post" a écrit dans le message de news: snipped-for-privacy@w1g2000hsg.googlegroups.com...

Are you sure your 10 N force is vertical and not perpendicular to the bar or the "2"? This last case would make it rotate.

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Jean Marc

"Jean Marc" a écrit dans le message de news:

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Meant the bar OF the "2"

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Jean Marc

Try fixing the long part and apply the force to the hook.

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Johns Yard

wow.. why is my post laid out so ugly? (sorry)

Jean Marc, yes, the force is vertical down (-Z). The load is fine.. its my restraints (or lack thereof) -- that i'm unsure about.

The center of gravity of the coat hanger is slightly off to one side.. I would expect a slight rotation of ~5degrees of so -- but not this much (~30deg off vertical). Again, i fear that its either

  1. a misapplication of a Contact Surface, or,
  2. a missing restraint.
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