I am modelling RC Beam for investigating shear in Abaqus, In Abaqus manual it states
"Beam elements do not yield accurate results, if the beam cross sectional dimension is smaller than the 1/10 of the dimension in transverse direction"
I have 18" depth where as the beam length is 148"
and If I consider a continuum element , It does not have rotational DOFs
Can we add the rotational DOF in continuum elements?
What should be the right element family to take to model the beam
Hi,
I think you should use the solid elements (8-nodes) for concrete beam, and beam (truss) elements for the rebars. Please be noted that you have to consider the bond between concrete and rebar. One of the good way is to use Lagrange_in_solid.
Good luck!
Hi,
I think you should use the solid elements (8-nodes) for concrete beam, and beam (truss) elements for the rebars. Please be noted that you have to consider the bond between concrete and rebar. One of the good way is to use Lagrange_in_solid.
Good luck!
Continuum elements do have rotational DOFs. Consider a section, get rotations of all nodes within the considered section and then average them. Another alternative is to obtain curvature of the section from the developed axial strains and then obtaining the rotation from the calculated curvature.
In your case the depth to span ratio is roughly 1:8 and I seriously believe you can still use beam elements with Timoshenko formulation.
There are three models for your purpose:
1_ Individual Rigid Beam Model (IRB).
²_ Parallel Multi Rigid Beams Model (PMRB)
3_ Solid Element Model (SEM).
For models 1 abd 2, the best number of nodes is 16 or 32 and for model 3 the best number of nodes is 16 or 8.
You can use from these elements for both concrete beam and rebars. In the case of 32 nodes, the time of calculation is more respect to 16 nodes.
Hi,
I would always use continuum finite elements, preferably with quadratic shape functions (10-node tetrahedral finite elements or 20-node hexahedral finite elements). The reason is that solid elements are not based on a dimensionally reduced theory like beams are. Even if you use Timoschenko beam elements you will also in the limit always only recover an approximate solution, especially to your shear problem. Using continuum elements you obtain the exact solution (theoretically) if your elements are infinitely small.
Best regards,
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