non-linear contact analysis

[Nastran994]

Hello, everyone! !
do any of you have any special advice to give me or would you recommend some tutorials/manuals in particular to perform a nonlinear contact analysis on a plastic deformation? I should do this with patran/nastran, but I've never been in such a complex analysis! !

 

[Onda]

set the analysis as a simple linear and solve contacts and leads to convergence.
then put the nonlinear material and repeat the analysis. Basically, go by step.

 

[Nastran994]

set it as simple linear you want to set the material as elastic? ?

 

[Onda]

That's right. put the elastic material. and set the analysis with contacts. you can also initially use the linear solutor. then proceed with the non-linear solutor. then change material,. In this way you can keep track of changes on the results of each change and the times and ways of convergence.

 

[Nastran994]

great thank you so much, maybe proceeding so by step is even easier!! I just miss understanding how to make contact! !
As I should make contact between two objects (tool and piece in an operating machine to understand us) I should import the two geometries differently or make a set on cad save it as .igs and operate like this? or is it indifferent?

 

[Onda]

it is better to use step files for import into patran. Even better, if you have the license, import into parasolid. it would be useful that you put them on two different groups, so you can quickly turn on and turn off one or the other. to do this, or make two separate imports, or move them once imported.
attentive to the units of measurement when it amounts!

 

[Nastran994]

Why would parasolid be better?? What's the difference with the stp file?

 

[Onda]

because Patran loads the step parasolids better. you are more likely to recognize them as closed solid bodies and not as a set of surfaces. necessary condition for meshare them as solids with square tetrahedra. do not use linears, do not work.
In any case, do various tests, first with parasolid, then with step if it doesn't work. If this doesn't work, use iges, but then you have to do a reconstruction job...
In case there were problems, there are various strategies to get to the solid mesh, but in the meantime try to import the models.

 

[Nastran994]

for now I was working with the .igs and I was not having so much trouble in the mesh, but if a priori are better the steps I make some attempt with those