mechanical Apdl

[rahul013]

Hi
I am doing static structural analysis. The problem is that when we input the result in the program to get the contour plot, the von mises stress values of the contour plot, are different compared to the result that we had.
Does anyone know why is this happening?
It is so urgent............

 

[Dave442]

Hi Rahul,

As you have not described the process that you are trying to model or the features of your FEA model it is impossible to say why your FEA results do not match up with your experimental results.

As a first step you should check the following:

1) System of units - Are they consistent?
2) Model geometry - Is it correct?
3) Finite element selection - Are they suitable?
4) Mesh - Is it suitable?
5) Material models - Are they suitable? Are they properly defined?
6) Boundary/loading conditions - Do they accurately model the loads/constraints of the system you are studying?
7) Solution controls - Are you modelling nonlinear effects? Is NLGEOM turned on?
8) Results - has the solution converged? Are you post-processing your results correctly?

If you describe your model in greater detail you may get better feedback from the forum.

Good luck,
Dave

 

[rahul013]

SIr,
My model is helical compression spring. I want to do static stress analysis.
As you replied solution converged, may you tell how solution can be converged?? I know it is basic question but really i don't have any idea about it.
Please reply sir.
Thanks

 

[0rel]

As I already told you, stresses in compression strings are known with basic, verified formulas.

If you really want to view these stresses in Ansys, try viewing maximum or minimum shear stress as compression springs are mostly showing shear stress.

Von Mises won't show you anything in that particular case.

 

[rahul013]

Orel sir,
I also calculated max & min shear stress value in ansys but those values are also different while compared to resulat that i had.

 

[0rel]

Give a screenshot of your load & BCs, can't help you with nothing.

Also, what are the results that you have (those you want to compare von Mises stresses to), how did you get them ?

 

[rahul013]

Orel sir,
I send you data.

 

[0rel]

Well an image showing your BCs and load would be appreciated. No need for a file to send 10 lines of text...

When you write : "(i select some node of bottom surface and choose all degree of freedom and put 2 value)."

What do you mean by "some nodes" ?


Plus, are your endcoils ground or not ?


Here is a paper that might interest you :

http://www.irnetexplore.ac.in/IRNetExplore_Proceedings/ICMIE/ICMIE_16thJune2012/ICMIE/paper13.pdf

 

[rahul013]

Thanks.