Stress criteria
Stress criteria
(OP)
Dear members,
I doing a static structural nonlinear analysis (Bilinear material curve with contact pairs) of a steel structure using ANSYS classic.
The von-mises stress is less than yield strength but the first principal stress exceeds the yield strength (both von-mises & first principal stresses are developed at same location).
How the result can be concluded, based on von-mises or first principal stress?
Thanks in advance for your supports.
Ankser.
I doing a static structural nonlinear analysis (Bilinear material curve with contact pairs) of a steel structure using ANSYS classic.
The von-mises stress is less than yield strength but the first principal stress exceeds the yield strength (both von-mises & first principal stresses are developed at same location).
How the result can be concluded, based on von-mises or first principal stress?
Thanks in advance for your supports.
Ankser.





RE: Stress criteria
the question you need to ask yourself is "is the FEM prediction really valid ?" have you got a solid model with 1 element through the thickess, and so unreliable stresses ? is there something in the loading that might reduce the beneficial multi-axial tension ??
you can use either vm or max principal as a failure criteria; don't IMHO use the minimum of both, that's an each way bet ... it's conservative to be sure. vm is a perfectly valid failure criteria.
RE: Stress criteria
Do an elastic analysis and assess your stresses using design code standards for your particular structure.
Tata
RE: Stress criteria
rb1957, I am using SOLID92 (10 node tetrahedral) elements with good density across the thicknesses.
Also, yes, there is muti-axial tension due to loading.
Thanks,
Ankser.
RE: Stress criteria
you might calc a vm stress based on the two in-plane principal stresses.
RE: Stress criteria
Nagi Elabbasi
www.veryst.com