bolt modeling with two plates with 3d elements

[Luca Carciofi]

Hello everyone,

I compliment the forum and who's behind it because I've been very helpful during my work and how to make a regulation.

I currently use version 14, I have both the wb and the classic.

I'm modeling a simple 3d plate with two ansys bolts (I attached a photo below showing the problem I have to study, although in my case I don't have 3 bolts but 2) the plate is loaded into an extremity with an orthogonal load to the bolt axis (creating a cutting problem in the bolt) and in the atra extremity' is bound.

He's got some questions to ask and I'm sure I'll find the right answers here:

1)to analyze a problem so you advise me to use the classic or the wb? why is there a law for when it is better to use one or the other version?

2)I tried to import a .iges model from solidworks (a simple component with a pier of holes) but importing it does not create the volume, it only creates areas with errors. that imported piece I can meshiare it or if I amount a 3d element I must have a volume for meshiarlo?

3)How can I manage contact between the plates and between the bolt and the plates? with which at least? in defining the contact I have to define a master surface and a slave? using the 175 surface to surface element is right?

4)to insert friction between the plates how can I do? I have seen in several treaties use an friction of 0.3 or consider it null

5) how to model the bullion preload: I saw a lot of possibilities
a)thermal strain preload
b)prets179 preload simulating bullion preload

6) such a problem would you consider it linear elastic for small shifts? to consider the problem in plastic environment how can I do?

I thank you in advance only for reading the article.

hello to all and thanks again

 

[pollo]

only to subscribe to the topic.
But with something so simple, don't you do a hand check first?

 

[Luca Carciofi]

Hello chicken

you are right, I will also do that type of simulation, but my job is based on comparing the case3d, the case calculated by hand, and the other simulations that you can do using other elements to simulate the bolt. so I need to reproduce this type of simulation. .
Do you have any advice?

Thank you

 

[pollo]

Okay. Sorry, but then I don't know how to help you. Good luck. Hi.

 

[Luca Carciofi]

OK hello chicken thank you anyway.
Hi.

 

[stefano.garbin]

1)to analyze a problem so you advise me to use the classic or the wb? why is there a law for when it is better to use one or the other version?

use what you like! apart from jokes if you do not have much experience you should start with workbench which in any case for the type of problem you face is more than good.

2)I tried to import a .iges model from solidworks (a simple component with a pier of holes) but importing it does not create the volume, it only creates areas with errors. that imported piece I can meshiare it or if I amount a 3d element I must have a volume for meshiarlo?

Given that iges is a neutral format that often and willingly from a lot of problems, did you import it into classic or wb? classic and wb have totally different modeling kernels, wb should give you much less trouble. try also to use the step that is best.

3)How can I manage contact between the plates and between the bolt and the plates? with which at least? in defining the contact I have to define a master surface and a slave? using the 175 surface to surface element is right?

in the definition of contact surfaces is ansys that cares to choose the contact elements and to "spalmarli" on the surfaces.

4)to insert friction between the plates how can I do? I have seen in several treaties use an friction of 0.3 or consider it null

Expenses from the state of contact surfaces, material, and from one hundred thousand other things.

5) how to model the bullion preload: I saw a lot of possibilities
a)thermal strain preload
b)prets179 preload simulating bullion preload

I would go for hypothesis b. found a good table that relates the size of the screw, threads and torque with the axial force.

6) such a problem would you consider it linear elastic for small shifts? to consider the problem in plastic environment how can I do?

Leave plasticity for the moment. simple parts neglecting non-linearity of material.
having contact surfaces and wanting to take into account the stem of the screws that collide to cut with the holes remembered to make a non-linear naalysis.

 

[Luca Carciofi]

stefano thank you for your advice, very helpful.

two more questions to better understand:

1) I know the difference between linear and nonlinear analysis but why do I recommend doing a nonlinear analysis?

2) if I want to insert beam elements or spiders or rbe in ansys workbench to simulate the bolt (maintaining the plates in 3d or as shell elements) can I do it?

Thank you very much

 

[stefano.garbin]

1) of the non-linear it because if you draw the screws perfectly in axis with the holes the screw stem is not initially in contact with the edge of the hole. then tractioning takes place contact. therefore there is a change of the matrix of rigidity of the system that requires a non-linear analysis.
2)Inserting beam elements or using rbe in workbench is more complex and requires you to insert "command snippet" into apdl. otherwise use the classic.