I am running 3 point bending simulation for a hybrid structure using two different material properties. I used elastic data and a stress-strain curve. However, the curves are not smooth for the explicit solver but I get a smooth curve for the static solver. I need to use the explicit solver to keep terminology consistent across my paper as I am using crushable foam for compression tests.
For your information, I have tried:
- finer mesh
- bigger time period (10)
- smaller steps in Amplitude
-Increased interval in output
- used both discrete and analytical for support and load-cell
Neither of the above steps helped to get a better smooth curve. I am not sure what is the problem, or this type of behaviour is normal for explicit solver results as I saw many papers has similar type results.
Many thanks
Armin
In spite of the information you have provided (e.g., finer mesh, bigger time period, etc.) there are still essential details missing so that we are not able to answer the question. For example, 3-point simulation of what using which equation or software? What static model? If this is indeed "crushable foam" why would you expect a smooth response?
I have updated the question. I am not using crushable foam for bending, I used a plastic model.
I used crushable foam for the compression test and the results are okay.
The problem is that I can get a smooth curve using a static solver but not an explicit solver for bending simulation.
Dear Armin
If the simulation consists nonlinear analysis, the displacement (load) must be applied incrementally. Therefore, the hybrid structure changes at the end of each step and an update of the system matrices might be considered. With using Dynamic Explicit: At the end of each time step the update of the system matrices will be executed and the new system of equations will be solved without iteration. If the increments are small enough accurate results will be computed, otherwise the solution will diverge. This is due to the fact that the equilibrium is not strictly enforced. On the other hand,with the use of implicit scheme : The approach is analogous to the one discussed for the explicit system with the difference that in each increment the Newton-Raphson algorithm is applied to iterate the equilibrium. Therefore, larger increments are possible and the accuracy is typically higher as in the explicit case. But it is also numerically more costly since the system matrices are also updated in the Newton-Raphson iterations. Standard is more efficient for solving smooth nonlinear problems; but in some cases Abaqus/Standard have difficulty converging because of contact or material complexities, resulting in a large number of iterance's.
Good luck
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