I wanted to do FEM analysis of an RCC beam in ABAQUS. I have made the stress strain curve using some mathematical model and developed the Compressive and tensile stress strain curve and also the damage parameters using some formula from Literatures. But i am not getting the tensile and compressive damage as per experiment. Please suggest me what i need to do. I have the following doubts:

1. I extracted the CDP parameters from literature like dialation angle, eccentricity, by-axial stress/Uniaxial stress, viscosity parameters etc. for input in ABAQUS. Is it necessary to find out those parametrs or i can use the parameters that are available in literature.

2. After analysis i am getting the midspan deflection directly proportional to the mesh size. That is if i am using finer mesh size i am getting very less deflection and vice versa. which is contradictory to theory.

3. If i am unable to get the result correctly what i shall do to bring the result shall i play with parameters of point no. 1 or the damage variable.

4. Or i shall take the experimental stress strain curve of concrete and steel??

Please help me .....!!! I need your help