Interfaces in Mechanica

[ptc-1856114]

I have a plate sitting on top of two surfaces with a load applied to the top of the plate. I am trying to measure the displacement and stress on the two components holding the plate up. If I just mesh the model, it assumes the two pieces are bonded, which is incorrect. If I put rigid connections between some bolt holes on the parts and the plate, the plate flexes, but the load does not affect the other two parts. The same thing happens when I put interfaces between the contacting surfaces. Any ideas on how I can get my analysis to run correctly? Thanks.

[RickGiguere]

"Ryan Seefeldt" wrote:

I have a plate sitting on top of two surfaces with a load applied to the top of the plate. I am trying to measure the displacement and stress on the two components holding the plate up. If I just mesh the model, it assumes the two pieces are bonded, which is incorrect. If I put rigid connections between some bolt holes on the parts and the plate, the plate flexes, but the load does not affect the other two parts. The same thing happens when I put interfaces between the contacting surfaces. Any ideas on how I can get my analysis to run correctly? Thanks.

[RickGiguere]

I've been playing around with this, and I get different results, depending on what kind of connection is used and if I offset the surfaces in assy. I'm going to stay out of these Mechanica problems. good luck I put a two holes through the plate and in the two support brackets(cylinders in my case), and applied ridged links around the edges of the hole on the cylinder and around the holes on the plate, and applied a 0.001 inch clearance between the plate and support bracket in assy., and seemed to get good result. But I get different result if I change something.

[RickGiguere]

BTW the first method I suggested was giving me warnings on a bad connection.

[RickGiguere]

"Richard Giguere" wrote:

I've been playing around with this, and I get different results, depending on what kind of connection is used and if I offset the surfaces in assy. I'm going to stay out of these Mechanica problems. good luck I put a two holes through the plate and in the two support brackets(cylinders in my case), and applied ridged links around the edges of the hole on the cylinder and around the holes on the plate, and applied a 0.001 inch clearance between the plate and support bracket in assy., and seemed to get good result. But I get different result if I change something.

[ptc-1856114]

"Richard Giguere" wrote:

When placing constrainment refs in assy., try offsetting the surface between the plate and the two surfaces, so Mechanica won't assume they are sharing the same surface and bond them, then use connection > auto define between the plate and two surfaces. There was another poster that had a similar thing between two cylinders. Hope it works

[RickGiguere]

I tried using interfaces with a coincident ref = didn't work, plate passed right through the supports. Tried using auto detect with a 0.001 inch offset ref = didn't work, plate passed right through the support. Tried using a coincident ref with no connections = worked, but the two parts acted bonded. Tried using a ridged link around the two bolt holes on the plate and support, with a 0.001 inch offset ref = worked, but the two parts acted bonded. Tried using a 0.050-0.075 inch offset with various links, and got fatal error messages. I couldn't get it to work without it being bonded in some fashion.