Stiffness degradation of steel rods with time using Abaqus/Explicit

[abdu90]

Hello,

I am modeling a reinforced concrete beam under cyclic loading using Abaqus/Explicit. In my model I am trying to simulate the effect of time on the stiffness of the steel rebars using random fields (Each steel element should have a different young's modulus). As the time increases the stiffness of the rebars decreases. Truss elements are used for rebars.

The idea of the model is at time 1sec for example there is 25 random fields (25 values for young's' modulus along the length of the rebar). I want to do this for 20 sec or more. The only way to make this work was by creating s field matrix (when t=1sec field 1 is from 1-25 and all other fields are zeros) as shown bellow. However, if I increase the number of fields to more than 5 fields Abaqus gives this error. To implement this I have written a VUSDFLD as shown below:

My questions regarding the subroutine and my methodology are as the following :

1- According to my description of the model, is the methodology correct ?
2- Is there is a better way to do this ?
3- Is there is a way to define for example 20 different materials for the steel and change them with time using the subroutine ?
4- Should I change any thing in my subroutine ?

 

[FEA way]

Check the output files for additional error messages, they might indicate the actual cause of the problem.

Have you considered doing this analysis in Abaqus/Standard ? It’s usually a better choice when simulating longer time periods.

There is a research paper that might be helpful for you: "Multiscale Concrete Modeling of Aging Degradation" by Y. Hammi et al.