How is the timestep computed for beams in Autodyn/Explicit Dynamics?
Generally, timesteps are determined in Autodyn/Explicit Dynamics for solid and shell elements based on a global timestep safety factor (TSF):
timestep = global TSF * computed timestep
For beam elements, there is an additional beam timestep safety factor and the timestep is computed as:
timestep = beam TSF * global TSF * computed timestep
This additional beam TSF is necessary because of stability issues in case of large deformations.