Does Adams View follow the specific rule to calculate the cm marker orientation?

I have a Damper, I used ORI_IN_PLANE to parameterize the orientation of the piston and cylinder. When I apply the function I get exactly the same orientation (design variable still is the same-standard value). However cm-marker orientation is changed! Does anybody know why? how can I control that without parameterizing the cm marker. I want AView to automatically calculate the cm-marker coordinates.

0 Henrik.Skovbjerg over 4 years ago

If you want AView to automatically calculate the cm-marker coordinates, why do you care how it is oriented. You don't need to look at the orientation of the cm-markers at all. If you need markers to measure on, you should create other markers.
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0 fatemehh over 4 years ago

@Henrik Skovbjerg Because every small change in the cm-marker position or orientation will affect the result. now I am at initial condition and the results should not change when I am not changing the location and orientation of the body. I just applied a function that is giving me the same orientation. Logically, I have to get the same cm -marker. However, AView changes the cm-marker.
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0 Henrik.Skovbjerg over 4 years ago

If you have Adams calculate the cm-position, then this is done based on the geometry on the part. If you move the geometry, then the cm-marker will follow this move. If you orient the geometry differently, then Adams will re-calculate, and if e.g. the orientation of the cm-marker is changed, then the inertias of the part are also changed.

Note that all this is done at DESIGN TIME. Once you start an analysis, there will be no changes for the cm-marker or the inertias. Adams will not re-calculate any mass or inertia during analysis.
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0 fatemehh over 4 years ago

@Henrik Skovbjerg When I do the simulation after and before applying the function, the results are not the same. The cm marker changes before running the simulation ( DESIGN TIME-right after applying the function), that is why the results change. My objective is to avoid the variation of the cm marker to keep the results the same when the geometry and orientation are the same. Why does the cm marker change when the function is making exactly the same orientation?
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0 Henrik.Skovbjerg over 4 years ago

I am not sure what you could be doing that would give different answers for the same geometry.

I would suggest that you model the parts as they should be, and then switch the mass properties to user-entered. That way they will stay fixed and you can do whatever you want with respect to parameterization of the parts.
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0 fatemehh over 4 years ago

Attached is my damper after parameterization. I used ORI_IN_PLANE, the piston orientation is exactly the same as initial orientation, since I used mathematical relationships to calculate the XY plane for the ORI_IN_PLANNE function.

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dmp_IN_PLANE.cmd.zip
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0 fatemehh over 4 years ago

@Henrik Skovbjerg This file is my initial damper. If you see the piston location and geometry and orientation, all are the same, however cm-marker (piston) is NOT. This damper is a part of a complicated structure I cannot use user-defined option for cm-marker. There should be a relationship in Adams for calculation the center of mass.

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dmp.cmd.zip
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0 Henrik.Skovbjerg over 4 years ago

I am not sure what you are pointing at. The two models show the exact same mass properties.

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0 Henrik.Skovbjerg over 4 years ago

Second model ...

Showing the part mass properties through the Table Editor for each model

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0 fatemehh over 4 years ago

@Henrik Skovbjerg Did you check the orientation of the cm marker for the DAMPER_RR_PIS ?
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