Modeling Shear Walls in Ansys

[davejryan]

Hi all,
I need some advise on modelling shear walls in Ansys. What element types are best to use and what are the advantages/ disadvantages of plane and shell elements? I am currently using shell type 63.The actual building will have 400mm thick walls.Any comments would be greatly appreciated.
Thanks

 

[Drej]

In the past I've used plane stress elements to model shear walls, but that wasn't using ANSYS. The first thing to mention is that I assume it's a masonry structure? If this is the case then in ANSYS you need to be looking at the SOLID65 element, which is the only element capable of handling the concrete (TB,CONC) material model (and it is a 3D brick). On the other hand, if you're not interested in cracking/crushing/tension softening/secant moduli/etc. then you could possibly use one of the plane elements:

(42, 82) -> all things being equal, I would choose this method (less computation burden and a simple model)
(63, 93) -> would be concerned with the large thro-thickness and whether this influences the result
(182, 183) -> as per 42/82 but with better non-linear formulations


This all depends on your structure and whether it's symmetric, or whether it has rebar or other localised embedded stiffeners. The beauty of using the SOLID165 is that you can easily define these stiffners. If I had a nice simple linear structure with no rebar, and I had to choose, I'd go for the plane82 (as a plane stress option). (Just in case I'd do a simple correlation of the results with a simple 3D brick model as well.)


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[davejryan]

Thanks Drej for getting back to me so quick!
The shear walls are concrete panels about 5.4m wide and 4m high but I'm not too interested in cracking/ crushing(just yet). Its a modal analysis that will be carried out.
The plane 42 element only allows me to model the walls in the x y plane only. When I try and mesh walls in the z direction the error message says the area is not parallel to the global x y plane and it cannot mesh with 2d planar elements. I know why this is but is there any way of using plane elements for my shear walls in both directions (in both the x y plane and z y plane) and getting around this problem? I have been using shell 63 elements thus far but have assumed no out of plane bending so a plane element could be used. The model will eventually be quite large so anyway of reducing computational time would be advantageous! Is there any plane element type that allows me to model in more than one plane?Thanks again for the help.
Regards

 

[Drej]

Well, to be pedantic, the shells you are using are also plane (stress) elements. There's no way you can use the plane42/82 outside of the x/y plane - check the DOF for these elements in the help file, which show ux/uy only. Must admit was surprised by your usage of shells (not allowing out-of-plane bending) which I'm sure is not realistic. Why are you restricting the out-of-plane bending? It also sounds like this problem is 3D rather than 2D(?) At the same time I can't picture why you would use shells or any other plane element in any other plane than the x/y plane? Unless you have stiffeners/gussets/something acting out of plane?


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