[MBDyn-users] Input mistake

Pierangelo Masarati masarati at aero.polimi.it
Wed Aug 5 17:33:42 CEST 2009


Romuald NORET wrote:
> Hello,
> 
> I am trying  to modelize a car steering (very simplified one) and to 
> monitor kinetic by appling a displacement (last joint into the input 
> file). But I had to make a mistake somewhere because computation runs 
> without crashing but no movement happen. You can find enclosed the input 
> file "steer" (which requires 2 others files "steer.id" and "steer.ref").
> I will be very grateful if someone could explain where my mistake is.


Dear Romuald,

in joint JOINT_DISP (the total joint) you define the position constraint 
as "active" (which means "constrained") only in direction 1, but the 
vector of the imposed motion is zero in direction 1, and non-zero in 
direction 2.

Probably, you either meant to impose motion in direction 1, and thus you 
need to change the vector from 0., 1., 0. to 1., 0., 0., or you meant to 
impose motion in direction 2, and thus you need to change constraint 
equation activation to "inactive, active, inactive".

Hope this helps.

Cheers, p.


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