DEFORMABLE_TO_RIGID is a real life saver. It can reduces the run time of your analysis from hours to merely minutes. In the starting part of the simulation, the vehicle rolls and falls to the ground due to the gravity load. At this time, we are not interested in any deformation or stresses, thus in this part of the simulation, all the deformable parts are converted to rigid.
The top two panels are the analysis with DEFORMABLE_TO_RIGID. The graphs in the left in panels are the resultant velocity of centre of gravity (measured from the accelerometer part), while the ones on the right panels are for the resultant force of front right spring.
Rollover analysis is usually performed on bus superstructures. However, since I cannot share the bus files publicly, I replaced it with a pickup truck to showcase the application of DEFORMABLE_TO_RIGID keyword.
For more readings regarding Deformable_to_rigid application in bus rollover, check out this (available online):
Zhu (2009). Delopment of guidelines for deformable and rigid switch in ls-dyna simulation
