Motion skeleton and dynamic analysis

[wildfirebrigade]

Ive been working for weeks on an excavator arm using a
motion
skeleton. Now i want to do a dynamic analysis of a
movement using
servo motors on the cylinders, to optimise the parts later
in mechanica.
However i get an error when i dont give the skeleton parts
solid bodies
with mass. But if i do give them solid bodies i wont get
realistic results
from my analysis?

 

[solidworm]

im not sure if its possible to do dynamic analysis on skeleton parts, but theoretically to be able to do dynamic analysis you need to assign mass properties and moment of inertia values of the mechanism member (which involves calculation of center of mass and determination of principal axes of inertia), as for the validity of analysis results, you should be careful not to over constrain your mechanism(over constraining isn't a problem in kinematic analysis, but invalidates dynamic analysis results), i haven't used MDO for a while, but if you you upload your mechanism,other users, specially Kaz, may weigh in and give you some hints, to get valid results out of your dynamic analysis.

 

[Mech2003]

I'm having similar problem with Creo Parametric 2.0. I've created Top-Down motion skeleton in asm. In this same asm I have solid parts which includes copy geometries of skeleton bodies. These parts are assembled to corresponding motion skeleton bodies by using csys. When l try to set dynamic analysis it gives that same error message. So... Should I copy inertia from parts and run dynamic analysis only for motion skeleton asm?

I did not use automatic joints. I Invoked dialogue and copied geometries and created connections manually for skel parts.