What is the difference of adding reinforcement details of a concrete slab while doing modal analysis
I want to perform modal analysis of a simply supported concrete slab. And I am wondering if it is ok to just model the bare concrete slab and perform the modal analysis. Or does it make a huge difference in the results if I add the reinforcement details as well?
Best Answer

jjdoyle PittsburghMember
It depends on how much the rebar influences the overall mass (M) and the structural stiffness (K) in the equation f1=(K/M)^2 and how complicated the geometry is. The stiffness is a function of the modulus. The mass is a function of the volume and density.
If the geometry is simple enough, perhaps you can calculate an effective modulus and equivalent density to represent the composite of concrete and rebar so you do not have to include the discrete rebar in the model.
If you are doing this for first time, you should build a small simplified representation (with and without the rebar) to validate the assumptions.
Answers
It depends on how much the rebar influences the overall mass (M) and the structural stiffness (K) in the equation f1=(K/M)^2 and how complicated the geometry is. The stiffness is a function of the modulus. The mass is a function of the volume and density.
If the geometry is simple enough, perhaps you can calculate an effective modulus and equivalent density to represent the composite of concrete and rebar so you do not have to include the discrete rebar in the model.
If you are doing this for first time, you should build a small simplified representation (with and without the rebar) to validate the assumptions.
Thank you jjdoyle! Ya, I am trying Ansys for the first time. Actually I am trying to solve a problem in acoustics and I came to know about Ansys in the process. Its about impact sound transmission via floor between two rooms. Any hints on how to solve this would be highly appreciated. Thank you.