Good evening, I have a problem with the mentioned command because the elasticity is defined as the tangent of the curve stress-strain for an uniaxial material, whose value would be similar to the modulus of elasticity. However, when I define the command Elastic Section, does the modulus of elasticity have the same value?. Otherwise, how I can calculate or estimate the elasticity using the modulus for the concrete?
I look forward to your answer,
Thanks in advance
Definition of Elastic Material
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NicolaTarque
- Posts: 5
- Joined: Thu Mar 12, 2020 3:40 pm
Re: Definition of Elastic Material
Hi, I was mentioning in another topic that the E in cae of lumped plasticity has to be defined twice, one for the elastic material and another for the hinge. In this last case, the E needs to be stiff enough in order not to add deformation due to the hinge.
Re: Definition of Elastic Material
When you define the Young's Modulus in the Elastic Section, it is meant to be the real elastic modulus of the material.
However, in our last webinar of RC frame structure we were dealing with lumped plasticity. In that case I was using a reduced "E" in the Elastic Section to take into account the cracking in concrete. Othewise, using the virgin elastic "E" would not match the results obtained with the fiber-based distributed plasticity.
Actually, you should not reduce "E" as I did (I did it for the sake of simplicity), since the reduced stiffness is necessary only for the bending part of the beam response (beacuse it is in bending that part of the concrete goes in tension with no strength), while in pure compression the "E" should be the tangent to the compressive stress-strain envelope.
So if you want ot be more precise, you can use an Elastic Section, with the real E and G, and then, instead of choosing the rectangular shape, you choose the "custom" option, where you can input the full area , so E*A is correct, and the reduced Iyy Izz so that the bending stiffness is properly reduced.
However, in our last webinar of RC frame structure we were dealing with lumped plasticity. In that case I was using a reduced "E" in the Elastic Section to take into account the cracking in concrete. Othewise, using the virgin elastic "E" would not match the results obtained with the fiber-based distributed plasticity.
Actually, you should not reduce "E" as I did (I did it for the sake of simplicity), since the reduced stiffness is necessary only for the bending part of the beam response (beacuse it is in bending that part of the concrete goes in tension with no strength), while in pure compression the "E" should be the tangent to the compressive stress-strain envelope.
So if you want ot be more precise, you can use an Elastic Section, with the real E and G, and then, instead of choosing the rectangular shape, you choose the "custom" option, where you can input the full area , so E*A is correct, and the reduced Iyy Izz so that the bending stiffness is properly reduced.