Modeling a Bending Moment Test

[WTCraig]

I am trying to simulate a bending moment test on a pipe coupling assembly. I have attached a diagram of the moment test and also the assembly file. I am trying to model the test as accurately as possible, but encounter many errors when I think I am choosing the appropriate fixtures and connections and can't get any realistic results. The pipes, sleeve, ram, and base are made of steel and the couplings HYLON N1013 (similar to nylon 6/10). The ram pictured in the model can be suppressed if needed. Any help would be greatly appreciated!

-William

bending moment test diagram:

http://files.engineering.com/getfil...227-982e-b64766e6eab1&file=bending_moment.jpg

model screenshot:

http://files.engineering.com/getfil...f2-4f4f-9c22-c70a110eb8fb&file=screenshot.jpg

 

[Andrea9898]

be more detailed.

which errors do you get?
how have you constrained the pipe? Looking at the picture it seems like it is not constrained at all..

 

[WTCraig]

Thanks for the quick response. This following how I setup the explicit dynamics module although I have tried a static structural with a load applied to the sleeve in the -y direction and the bottom face of the base fixed. The base is a rigid, fixed support body and the pipes are resting on top, body interactions are set to frictionless and all of the contact regions not touching the fixed support are set as bonded. I tried using frictional contacts and get errors saying the coefficient of friction has been changed due to contact forces or what not. I have ran the simulation countless times and have gotten errors saying "time step to small" and "energy error too large". After these errors I have tried making the meshes finer and adjusting the minimum CFL time from 1.0E-7 to 1.0E-20. The best results so far happen when I have all parts set to structural steel, but when I change the coupling material to polyethylene the ram shoots through the steel sleeve and deforms the pipes in an unrealistic manner. I have already tested the coupling assembly using and arbor press with load cell, so I know the modes of failure already, just trying to reproduce the results.

Model setup screenshot:

http://files.engineering.com/getfil...89-4d7f-943e-2aef2309b7f5&file=screenshot.png

Results when using all steel parts:

http://files.engineering.com/getfil...e-4ffe-b649-936da7d63ccc&file=screenshot2.png

Results when changing to POLYETH. couplings:

http://files.engineering.com/getfil...a-43b9-9a1a-2a8901f1e623&file=screenshot3.png

Thanks again,

William