I need help with simulation

hello everybody i have designed a hydraulic press and i want to simulated to see if can hold 15 tons of pressure. I have put all the necessary loads and fixtures but when i run the simulation crashes.In my opinion that happens because of bad component contacts.I have tried anything i know(not much about fea) but nothing. Anyone can help me i can send him all files to have a look. Thanks.

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5 Answers

It could be almost anything from that description. What kind of error do you get when it crashes? Is it asking to do a large displacement study?

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the type of problem was:preconditioner_fail_to_factor. To see in which parts i have the problem i went to properties of the study and turn on the soft springs stabilization and i didnt rerun with the large displacement flag turned on. The final warn i receive was...

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Without the files it is difficult to outright diagnose. If you have soft springs turned on and you are still getting a large displacement prompt you definitely have a contact problem (or multiple contact problems).

The trick now is to find where they exist.

Are you using bonded contacts? If so make sure you don't have interferences and the bonded faces.

Can you try to isolate the frame out of the study and just perform between the upper and lower cross members? That would isolate the problem between the two "assemblies". What I have found works best in these scenarios is try to simplify as much as possible and then work my way back up as needed.

You could try not using an actual ram (because you know it can supply the load) and just apply a load using a split line on the plate.

You may also try to fix individual components (fixed geometry). When you fix the component that is floating off you will not have large displacement and you have isolated your problem.

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Hi Aggelos,

Could you attach your files? Looking at the overall model, are you saying you are exerting a hydraulic clamp load of 15 000 N? That load needs to act on something. Or do you mean if the cylinder itself 'can hold 15 tonnes of pressure' of which it should be in Pascals or Bar?

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