how to control mass scaling and time step and TSSFAC,DT2MS, what is relation between them
Hi @nikhillonkar92,
So you are on the right path. Mass scaling is determined using *Control_timestep where at the minimum you need to define TSSFAC and DT2MS. TSSFAC is just the scale factor for the computed time step which is 0.9 by default. This can be lowered with higher energy simulations like explosions, but generally it's best just to leave it at 0.9.
DT2MS is where you input your desired minimum timestep for your simulation. So mass will be added to any elements that drop below this timestep in order to compensate. Also, it's important to know that negative and positive values for DT2MS will behave differently. Negative will only add mass to elements that drop below that threshold like I described above (I recommend this), Positive will add or remove mass from all elements to make the timestep the exact same for all elements of the model.
A lot more detail regarding mass scaling can be found here:
https://www.dynasupport.com/howtos/general/mass-scaling
Additionally, this link goes through how time step is calculated if you want some background on that front:
https://www.dynasupport.com/tutorial/ls-dyna-users-guide/time-step-size
hello,Can I continue asking questions?
I don't quite understand the marked section in the image. I set the set collection of -2000011 in IMSCL. Isn't selective mass scaling applied to the parts in this set? Why does it say "all other parts are mass scaled the usual way" here? Will parts not in the set also be mass scaled?
