Stresses are not matching with input data_ABAQUS

[Ravi K Mudragada]

I am struck in a small problem which I hope can sort out with your help. I am running an explicit dynamic integration problem for a fixed beam (3D solid) subjected to a triangular pulse on the top. I have used CDP for concrete. Analysis is converging without any error. But, resulting stresses are not matching with the input stress-strain data. It is not following the input curve (it is giving more stresses than beam capacity). After reaching the capacity of the concrete, stresses are continuously increasing till some extent and then suddenly started following the softening branch of the input curve. I have tried to check the stresses at integration points instead of nodes; tried with full integration; decreased the automatic time step..but nothing has worked out. Can please able to look into this problem. Hoping to hear from you soon. Thank you..!!

PLEASE LOOK AT THE ATTACHED FILE.

 

[FEA way]

At which location do you measure the stresses and strains ? How does the mesh look like ? I would also try to solve this with Abaqus/Standard.

 

[Ravi K Mudragada]

Mesh size is 100mm (i even tried with 50mm mesh but same problem).
length of the beam is 3m..i am checking the stress at 1.5m, top element.

 

[FEA way]

Different types of elements could also help, there’s a large choice of them in Abaqus and many are designed specifically for bending problems.

What’s the ultimate goal of this analysis ? Is that just a benchmark or will the model be used to perform some particular research ?

 

[Ravi K Mudragada]

I actually need to do some other analysis. But, first i need to check whether it is working fine (material models, geometric modelling etc.,). But i couldn't understand why this is happening. Even though i didn't find any convergence problems/numerical instabilities.