"Smart" initial displacement and velocity

Renga@MFRC

Hi

I am trying to set up a simple simulation as a practice for a larger more complex simulation. I am attempting to move a body downward (-z direction) at a constant velocity, then apply a constant acceleration, So when I use the motion command I need to input the the initial displacement and velocity. I know I could just put in -250 in for the initial displacement but I am trying to have a 'smart system' as this object will be interacting with a powder using EDEM co simulation, and I wont know the initial displacement of the body. I am trying to use DZ function but its not working, when the motion command is used the body jumps back to its starting position, as if I had entered '0' for ic_disp

my script is below, if I enter -250 for ic_disp it work as I want, B_0 is the body being move, and is the only body

<Simulate

analysis_type = 'Transient'

end_time = '5'

print_interval = '0.01'

/>

<Motion_Joint

id = '301001'

joint_id = '301001'

motion_type = 'T'

val_type = 'A'

ic_disp = 'DZ({b_0.cm.idstring},{Global_Frame.idstring})'

ic_vel = '-50'

type = 'EXPRESSION'

expr = '10'

/>

<Simulate

analysis_type = 'Transient'

end_time = '15'

print_interval = '0.01'

/>

Praful

Hello Edward - Here is how I did it (see attached model). A displacement type motion is used and a sensor is defined to capture the value of the displacement at the needed time. The value of that evaluation is used using the SENVAL statement to modify the motion.

In my example, the motion is deactivated initially to let the body fall under gravity, but this is not necessary. The motion can be active if needed.

 

Hope this helps.

 

Regards

Praful

Unable to find an attachment - read this blog