RCC beam with Coupled Damage Plasticity Microplane Concrete Model
I tried to simulate a Four Point Bending Test of a Reinforced Concrete Beam by creating a quarter model. CPT215 was used as concrete element and Reinf264 was used for steel rebar. I tried using steel plate as loading plate and bearing plate, but there was no change in the result so I removed them. Self load of the beam elements is not considered. The issue I am facing is the load displacement curve I am getting(green one) is not coinciding in any part with the experimental result(blue one) as shown in the attached picture. I tried to play with the material property parameters to see if I get better result. I got the new curve (red one) when I applied -
a. E=10000 (instead of 30142 MPa)
b. fut=0.95 (instead of 1.4 ) [CEB-FIP Model Code 1990]
c. Es=90000 (instead of 192000)E=10000 (instead of 30142 MPa)
I have noticed that I can lower the yielding load only when I change the material properties of the steel rebar. changes in material parameters of concrete do not have any effects on it.
I am not satisfied with the the necessity to change the actual material property of materials to this extent to get the curve I want. Also I am in doubt to see almost horizontal line after the yielding of tension rebar.
P.S. I also tried using Menetrey-William model with 186, but I had Error in Element Formulation.
Please suggest me measures to improve my FE simulation and get the reasonable results with resonable material inputs.