Simulation Mechanical and Multiphysics

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Member
Posts: 5
Registered: ‎08-02-2013

save contact

198 Views, 5 Replies
08-02-2013 12:16 PM

i have one model with 100 surface contact, i set this contacts(this spent very time).

i need change model with inventor,but i can't save contact situation for after edit model.

please help me about save contact situation for fem file in simulation multiphysics?

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zhuangs
Posts: 192
Registered: ‎10-04-2010

Re: save contact

08-08-2013 08:07 AM in reply to: 5221932

For your model with more than 100 contact, if you are using MES, you might try to use selection group to simplify the contact definition.

 

-Shoubing

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Member
Posts: 5
Registered: ‎08-02-2013

Re: save contact

08-08-2013 09:55 PM in reply to: zhuangs
i change model with inventor and this is hard for me define contact or group for any time?
i will save information about contact in the separate file(for example : read and save property of part file in multiphysics),but there is no option for this work
thank you for study and ?answer
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Valued Mentor
Posts: 459
Registered: ‎08-30-2012

Re: save contact

08-09-2013 05:33 AM in reply to: 5221932

5221932,

 

There is no command to save the contact information. So the best that can be done is to find a way to work with the capabilities that the software has. I have some questions for you that may help someone to provide an answer.

 

  1. What type of analysis are you using? (Linear? MES? Thermal? X?)
  2. What version of Simulation are you using?
  3. What version of Inventor are you using?
  4. How are you defining the contact? Are you selecting two surfaces at a time? Would it be possible to select two parts to define the contact? (I'm hoping there are fewer parts involved in the contact than there are surfaces.)
  5. If you were to change the default contact instead of defining 100 contact pairs, would there be fewer contacts to be defined to replicate what was the default contact? In other words, instead of using the default contact to bond 10 parts together and defining 100 surface contacts manually, just set the default to surface contact and define 10 bonded contacts manually.
  6. The most important question: what happens when you update the Inventor model and send it back to Simulation? Are all of the contacts missing? Are the contacts still there but are not correct? (The software should be associative with the Inventor model. In theory, it will match part X in Inventor to part Y in Simulation, even if the part numbering changes because of changes that you make in Inventor.)
  7. Do you have automatic contact detection turned on? (This is off by default, and I do not know if this overwrites the previously defined contact or not.)
  8. What type of changes are you making to the model in Inventor?
  9. Are you changing the model in Inventor, or are you changing the Inventor parameters directly from Simulation?
  10.  This might be helpful: what does your model look like? What's the purpose of the analysis? It is easier to provide suggestions when we know it is XYZ instead of having no idea what you are doing. :-)
John Holtz, PE
Mechanical Engineer
Pittsburgh, PA

16 years experience with Simulation Mechanical
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Member
Posts: 5
Registered: ‎08-02-2013

Re: save contact

08-09-2013 09:56 AM in reply to: AstroJohnPE
i use simulation and inventor in 2013 version,i choose surface with surface for define contact,but now select part with part and multiphysics itself automatically merge surfaces
merc for your guide.
some questions:

1- i have one spring with pre tension or pre strain,and i will analyse this model with linear sections in multiphysics,but there is truss element with pre strain ( instead of spring) ,only in nonlinear sections.

2- suppose we have one vibration system (with springs) with pre strain in springs and this pre strain had to modeled in system and then we go to main analyse,what is your method for model this system?

3- i try solve a simple model in natural frequency(modal) but may model have general contact(surface with surface),but there is no option for this general contact in linear modal analyse,and when i use this model in nonlinear modal analyse,multiphysics can't solve this problem (with general contact),and when purge this contact,multiphysics can solve it,why??
i'm sorry for many question's
in previous i used ansys and abaqus,but i like autodesk and, i don't know,why this strong software don't have ?strong help or book?
why i can only edit model in fusion software no in inventor?
why i can only transfer work point from inventor to multiphisics no from fusion and no solidworks to multiphisics?why?
how i orbit part in inventor with middle mouse?(for example orbit model with middle mouse in multyphisics and solidworks)
i'm sorry for many question's
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Valued Mentor
Posts: 459
Registered: ‎08-30-2012

Re: save contact

08-11-2013 05:31 PM in reply to: 5221932

Hi 522192,

 

For question 2, you can use a temperature difference -- thermal expansion -- to get the pre-strain that you want. strain = dL/L = alpha*dTemp. However you apply the temperature, just be careful that those temperatures do not cause the mating parts to expand or contract, too.

 

I cannot provide much insight for question 3 since most of those questions need a response from Autodesk.

 

How can any software calculate the natural frequency when it contains contact? By definition, there are no loads in a natural frequency analysis. With no loads, there are no displacements. With no displacements, how does the software know how much and where the contact is occurring?

 

I certainly hope you will take all of the answers that you receive through this discussion group and add them to the wiki help. If everyone did that, the Help would be the best in the world.  I know from personal experience that writers can only write about what they know or what they think of; they cannot write about something they have never thought of. ;-)

John Holtz, PE
Mechanical Engineer
Pittsburgh, PA

16 years experience with Simulation Mechanical
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