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Dear All,

I want to ask about RBE2 application, please see my picture below.

I have a simple plate, and I want to give constraint on 2 holes on top, and forces (160kN on both hole or 80kN each hole) on 2 holes on bottom

Why my simulation result (stress & deformation) totally different?, because in my opinion, case on the problem 1 and problem 2 are same....

Am I miss something?

Best regards,

Iron_Man

Part.PNG

Problem_1.PNG

Problem_2.PNG

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To me it should give different results.Point of load (distance)is varying.Any specific reason for using only specific nodes for creating RBE2/why not selecting all nodes of hole?

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@Rahul R,

Thank you for your response, you said "To me it should give different results.Point of load (distance)is varying" could you telling me more detail about it? or you have reference documents to understand about it?

 

"Any specific reason for using only specific nodes for creating RBE2/why not selecting all nodes of hole? "

I use RBE2 on half of hole to describe shaft contact area.

 

Thank you,

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Hi @Iron_Man59

 

I think in second case you will see a moment around the SPC point and your displacement results will be huge compared to first one. 

 

Instead leave SPCs as in case one and apply force/load as in case 2. Your results should match. 

 

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No no, I think it is due to another reason...

assume X is horizontal direction

in case 1, 2 holes with force can have X deformation 

but in case 2, they are impossible. rbe2 is similar to a rigid bar which constrained x deformation. so result of 2 cases will be different. could you check case 2 deflection is lower than case 1?

 

SPC and Force are same, but structure stiffness are different

 

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Dear All,

Thank you for your response,

@Prakash Pagadala,

"I think in second case you will see a moment around the SPC point and your displacement results will be huge compared to first one."

No, the displacement on problem 1 is bigger than problem 2, please see my picture below.

 

"Instead leave SPCs as in case one and apply force/load as in case 2. Your results should match."

What the problems that should be compared to your statement above? Problem 1 VS Your statement or Problem 2 VS Your statement?

 

@tinh,

"could you check case 2 deflection is lower than case 1?"

As what I mention above, YES, the displacement on problem  is lower than problem 1

 

All,

Please see my actual problem below, maybe you could give better solution how to model it on hyperworks,

 

Thank you,

assy_problem_sketch.png

 

 

 

 

Problem1 VS Problem 2_Displacement.PNG

Problem1 VS Problem 2_VMStress.PNG

Edited by Iron_Man59
Give better comparison pictures

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@Prakash Pagadala,

I see that the result on problem 1 (left picture (biggest one)) is similar with the result on problem 2 (right picture(top)), my question, which is better to use?

if you have reference to study about that problem above please share to us.

thank you

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2 minutes ago, Iron_Man59 said:

I never used RBE3 before, please give me guidance to use it (what is RBE3?, what is the differences with RBE2?, when to use it?, etc)

 

In short,  RBE3 does not add stiffness like RBE2

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Hi,

This video is working fine at my end. I just played the same in GOM player. Once the file starts click the video player screen and it will start.

Please try and update

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