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  3. Defining Gravity for New Templates in ACAR

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Defining Gravity for New Templates in ACAR

James Parkus
James Parkus 11 months ago

Hey folks,

I am trying to understand the finer details of how Adams/Car defines gravity when creating a new template, sub-assembly, and an assembly part. The model I'm working is not Earth Gravity and I've setup an "acarAS.cmd" command file to modify the already-created gravity vector.

This leads me to two questions;

  1. When and where does ACAR create the gravity vector and can I adjust the value there so I don't need to worry about using the "acarAS.cmd" file?
  2. If there are gravity vectors in templates set to Earth gravity, and then those same templates used in an assembly (via sub-assemblies) which has a gravity vector set to a non-Earth gravity (say Mars for example) – which gravity will be used in the simulation of the assembly?

Best,

James


Code for acarAS.cmd file

if cond=((eval(.system_defaults.units_consistency_factor )) == 0.)
default units length=meter mass=kg force=newton time=Second angle=degrees frequency=hz
view manage modify spacing_for_grid=1.0
end


color mod color=.colors.background red_component= 0.16 &
green_component=0.46 &
blue_component= 0.65 &
gradient= "none"


force modify body gravitational gravity = .__ACAR.gravity &
x_comp = 0.0 &
y_comp = 0.0 &
z_comp = (1.35(m/s/s))

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  • greg.wheeler
    greg.wheeler 11 months ago +1 verified
    Hi James. As of a few versions back, gravity is now saved in your assembly file, so you no longer need to use an acarAS script: [GRAVITY] X_COMPONENT = 0.0 Y_COMPONENT = 0.0 Z_COMPONENT = -4800.0
  • greg.wheeler
    greg.wheeler 11 months ago in reply to James Parkus +1
    Gravity defined in templates is ignored!
  • greg.wheeler
    0 greg.wheeler 11 months ago

    Hi James.

    As of a few versions back, gravity is now saved in your assembly file, so you no longer need to use an acarAS script:

    [GRAVITY]
     X_COMPONENT   =  0.0
     Y_COMPONENT   =  0.0
     Z_COMPONENT   =  -4800.0

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  • James Parkus
    0 James Parkus 11 months ago in reply to greg.wheeler

    Hey Greg, thanks for the explanation. Does the assembly gravity vector override any gravity vectors that would be specified in the templates used to make sub-assemblies which are then used to make the assembly?

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  • greg.wheeler
    0 greg.wheeler 11 months ago in reply to James Parkus

    Gravity defined in templates is ignored!

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  • James Parkus
    0 James Parkus 11 months ago in reply to greg.wheeler

    Very good, thanks for the help Greg!

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  • Jesper Slattengren
    0 Jesper Slattengren 11 months ago in reply to James Parkus

    Hi James. The acarAS.cmd method was probably something I set up originally. But as Greg explained, not needed anymore.

    And another thing to never forget:
    "In case of doubt, look in the adm-file". What's written there is what the solver will use.

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