Learning Forum

[edoniyasbirhanu]

100% REINF ELEMENT HAVE A HIGH VOLUME RATION THAN COMPARED TO BASE ELEMENT HOW COULD FIX IT IN ANSYS?

material model

concrete CPT 215

Reinf. reinf264

[Sheldon Imaoka]

The assumption when using REINF reinforcement elements is that the volume of that reinforcement is relatively low (we note this in the documentation, in Section 14.1 "Assumptions About Reinforcing" in the Structural Analysis Guide). This is because we don't 'subtract' the base material volume - we just add the reinforcement material. So if your reinforcement covers a large percentage of your base element, you may have too much 'stiffness' in your model acting in the direction of the reinforcement.
The warning is just to make you aware of that. Either you can accept the violation of this assumption in your model, or you would need to actually model the reinforcing if the volume of the reinforcements is very high. Another approach is to reduce the stiffness (elastic modulus) of the base material to compensate for the additional material, but be careful of this approximation since reinforcement material only acts in 1 direction, but your base material has stiffness in all directions, so reducing the stiffness is not ideal since you may be making your material have lower stiffness in modes of deformation not coinciding with your reinforcement direction.
Keep in mind that reinforcement elements are intended to provide easier modeling by not having to have geometry for your rebars or discrete reinforcements - the tradeoff is that since the reinforcements are essentially 'overlaid' on your base mesh, if the volume of the reinforcements is too high, you can be adding too much additional stiffness in the reinforcement direction (but not in other directions). If the reinforcements are so large in volume that they also provide stiffness in other directions (not just axially), it's probably better to model the reinforcement geometry.
Regards Sheldon