In a drop test simulation, during solving process DT keeps on decreasing with simultaneous increase in remaining time

ADITYA M

Hello,

We are developing drop test methodology (ISTA standards of drop test)using Radioss Solver for our product range . I have specified initial velocity for a specific height and gravity to drop against a rigid wall. We use Abaqus solver for drop test but now plan to shift towards Radioss. Mostly tied contacts are used in the simulation load case and the model is checked using Model check tool and is debugged. 

Average element size used for shell elements is 4 mm, 15 mm for Tetras. Overall element count is around 600k.

What could be the possible reasons for increase in simulation time ? 

Adriano_Koga

as you might be familiar, timestep in explicit analysis depends on a few factors such as minimum element size, or contact interface gap, etc..

It is hard to tell by looking only at this small portion of your .out file.

But it might be related to your elements hitting the wall and getting distorted, so that the element size is getting smaller, thus the timestep is also getting smaller and the remaining time rising.

Usually the .out file states who's responsible for the timestep, if it is nodal, or contact related (INTER).

 

I would check in details what the .out file is saying.

ADITYA M

Thank you, that was helpful.