How to get moment and shear from Solid stresses output
How to get moment and shear from Solid stresses output
(OP)
Hi all,
I model my concrete structure with solid elements in STAAD. How can i use stresses output results (corner stresses & centre stresses of element) to get bending moment, shear and Axial forces. From there I can design reinforcement.
Any references and examples will be very appreciated.
I model my concrete structure with solid elements in STAAD. How can i use stresses output results (corner stresses & centre stresses of element) to get bending moment, shear and Axial forces. From there I can design reinforcement.
Any references and examples will be very appreciated.





RE: How to get moment and shear from Solid stresses output
RE: How to get moment and shear from Solid stresses output
Ed.R.
RE: How to get moment and shear from Solid stresses output
However you should always bear in mind that by using the single values that come from the integrations you are "throwing away" a lot of information, perhaps the very information whose absence in simpler approaches caused you to resort to solid elements in the first place.
RE: How to get moment and shear from Solid stresses output
could you please provide more detail ? if you have any simple examples, it would be great
Thank you guys
RE: How to get moment and shear from Solid stresses output
Not sure I understand what you want....The forces acting on an area are simply the stress*area...If you plot the stresses normal (for the axial) and parallel (for the shear) to the section you are interested in you can then use numerical integration (via Simpsons rule, trapezoidal rule, or other rules) to determine the total forces...
If your concern is that you do not have the exact stresses at a particular node to make the plot just take the stresses from all adjacant locations (probably integration points) and perform a simple average of the values (while this may be off a bit when adjacent elements are not the same size it will be close enough)
As for the bending moments they are simply a combination of axial and bending stress....After you have the total stresses plotted normal to the surface you should be able to locate the neutral axis, remove the effects of the axial stress (not strictly necessary) and determine the bending stresses only....The integration of the bending stresses across the section is then the value of bending moment (sigbending = M y/I = sigi * yi)....
If I didn't understand what you wanted let me know and I'lll try again...
Ed.R.
RE: How to get moment and shear from Solid stresses output
B. Chepren
RE: How to get moment and shear from Solid stresses output
RE: How to get moment and shear from Solid stresses output
I think both rb1957 and I are interested in how you get direct stresses and forces (in specific directions) from Von Mises stress information. Please elaborate.....
Ed.R.
RE: How to get moment and shear from Solid stresses output
Attached (hopefully) is a paper I put together for evaluating the membrane and bending stresses from solid or axisymetric FEA elements. This is my opinion as to how to determine the needed stresses from the results of an FEA analysis.
It may not answer all your questions but it might provide some insight? The results of my analysis do match exactly with the published documents but the difference could be due to the approximation method used.
I took the liberty of using absolute values to more easily compare my results against the results from the source document. Review and comment if you want.
RE: How to get moment and shear from Solid stresses output
Basically what you are doing is correct but from a casual scan it looks like you have assumed that the neutral axis for bending is at the center of the section....This is not always true and the method should be modified to account for the neutral axis not in the middle....
Ed.R.
RE: How to get moment and shear from Solid stresses output
OK So show me how to do that. What should the equation look like?
RE: How to get moment and shear from Solid stresses output
More disscusion please
RE: How to get moment and shear from Solid stresses output
RE: How to get moment and shear from Solid stresses output
i think EdR's point was that you knew the section you were summing over, and imbedded this into your equations, nothing wrong with that.
RE: How to get moment and shear from Solid stresses output