simulation of a bolted joint in patran

[Sandrottt]

Good morning to all, my name is an alessandro and I am a master aerospace engineering student almost in term. I would like to ask for a consult on an exercise I have to carry out in the laboratory of structures. the title of the exercise is as follows: "Detail analysis of a bolted joint: analysis of the effects of the preload on the screw threads and breakdown of tensions between the constituting plates the joint".
to simulate tensions between the plates I thought to simulate the bolt with a spring element (cbush) attached to the plates with rbe3 elements.
to analyze the effects of preloading on threads I thought to use a cbeams element like bolt and analyze internal tensions. But I don't know why it sounds too trivial.
Do you think I should simulate the contact between the plates?
How could I simulate the contact between the bolt thread and a nut? to see the effects on the threads.
Thank you very much in advance

 

[Onda]

If you want to see the screw threads you need to model them, so you can't use a beam. But I didn't understand exactly what you should model.
two plates, a screw and a nut?
In this case, do you just have to give the preload or also model a load on the plates?
you could model everything with symmetrical elements, it becomes very quick the solution. the contact you can do with the contact elements or with the cgap technology, (you find so much literature on the net) the problem of the cgap that must be oriented according to the direction of contact, but it is in order to make two reference systems and put the knots.. the solution is very fast.

 

[Sandrottt]

If you want to see the screw threads you need to model them, so you can't use a beam. But I didn't understand exactly what you should model.
two plates, a screw and a nut?
In this case, do you just have to give the preload or also model a load on the plates?
you could model everything with symmetrical elements, it becomes very quick the solution. the contact you can do with the contact elements or with the cgap technology, (you find so much literature on the net) the problem of the cgap that must be oriented according to the direction of contact, but it is in order to make two reference systems and put the knots.. the solution is very fast.

Good morning wave thank you very much for the answer.
I just have to give a preload on the bolt. Let us say that the geometric model is to me to develop it. I have to bring stress values to the threaded part and to the plates. do you think it is enough to carry out a statistical analysis sol101? Thank you.

 

[Onda]

Yes, for the simulation only one 101, static. However, you need to use contacts. what is possible with the sol 101. As mentioned, the simplest solution is to model with symmetrical axial elements.

 

[biz]

Good morning to all, my name is an alessandro and I am a master aerospace engineering student almost in term. I would like to ask for a consult on an exercise I have to carry out in the laboratory of structures. the title of the exercise is as follows: "Detail analysis of a bolted joint: analysis of the effects of the preload on the screw threads and breakdown of tensions between the constituting plates the joint".
to simulate tensions between the plates I thought to simulate the bolt with a spring element (cbush) attached to the plates with rbe3 elements.
to analyze the effects of preloading on threads I thought to use a cbeams element like bolt and analyze internal tensions. But I don't know why it sounds too trivial.
Do you think I should simulate the contact between the plates?
How could I simulate the contact between the bolt thread and a nut? to see the effects on the threads.
Thank you very much in advance

you have to make a pattern that simulses lives and mothers, with asymmetrical elements to reduce computational burden and inflate mesh a lot. You cannot reduce the model to a beam if you want to see how threads work.
I invite you to post your results here. Thank you.