ASME III, Division 1 - Plastic Analysis (FEA) using Ansys 13.0
ASME III, Division 1 - Plastic Analysis (FEA) using Ansys 13.0
(OP)
Morning to All
We are designing a pressure vessel according ASME III, Division 1.
I'm checking the possibility of performing a plastic analysis using software ANSYS 13.0 but we have a concern: may I use this software?
In effect, at NB-3212, the Code specify that the teory of failure used is the maximum shear stress theory (Guest-Tresca), while ANSYS is based on Von Mises theory.
Thank you in advance for any suggestion.
Fabio
We are designing a pressure vessel according ASME III, Division 1.
I'm checking the possibility of performing a plastic analysis using software ANSYS 13.0 but we have a concern: may I use this software?
In effect, at NB-3212, the Code specify that the teory of failure used is the maximum shear stress theory (Guest-Tresca), while ANSYS is based on Von Mises theory.
Thank you in advance for any suggestion.
Fabio





RE: ASME III, Division 1 - Plastic Analysis (FEA) using Ansys 13.0
Just a note, however. Good engineering judgment (coming from someone who does this for a living) says that you should follow the rules in ASME Section VIII, Division 2, Part 5 if you are to apply a design-by-analysis (of, course, only if you are permitted to, per U-2(g)).
Also, please note that the ASME Codes are software neutral. Any particular software package is neither permitted nor prohibited. The general rules to follow are in the Code, but it is up to the individual engineer to determine how/if their software properly applies the rules.
RE: ASME III, Division 1 - Plastic Analysis (FEA) using Ansys 13.0
In any case ASME VIII Div. 2 follows Von Mises criteria (§ 5.2.3.5).
Thank you the same for replying.
Fabio
RE: ASME III, Division 1 - Plastic Analysis (FEA) using Ansys 13.0
My company uses an outside firm for our FEA. They use Ansys 13 and report the Tresca stresses. I'm not familiar with Ansys so I can't tell you how to do it, but I know it can be done.
RE: ASME III, Division 1 - Plastic Analysis (FEA) using Ansys 13.0
I agree that with ANSYS you can report both stress intensities (Tresca) or Equivalent stress (Von Mises).
But in a non-linear analysis, elasto-plastic type, the method of failure used is the Von Mises one. In other words yielding occur when elemental mean stress, calculated as per Von Mises criteria, reach the yield stress of the material.