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1-Visitor
Jul 6, 2021 2:36 PM UTC
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How to messure Leverage, Leverforce in Creo Mechanism

Hello,

 

is it possible to measure the lever force over time in Mechnism dynamics?
I have a simple lever mounted in the middle. On one side it is moved with a hydraulic cylinder.I know the displacement and the force in the cylinder. I would like to define these parameters. The vertical force that acts on the other side of the lever, I would like to show over the cylinder length or the time.

Is this possible? Unfortunately I did not find anything in the help.

 

Greetings
Morian

17-Peridot
Oct 9, 2023 6:09 PM UTC

Use a large damper to make the simulation quasi-static.

This is a solution for finding a series of static balance forces along a change in configuration for any mechanism.

 

To do this you need to use a quasi-static style of analysis. If you add a large damper as shown with long simulation time duration so inertia effects are negligible, you can get the force out vs cylinder extension. This is still a dynamic analysis requiring mechanism dynamics extension.

A constant force motor was applied at the cylinder and the net load measured at the damper.

If concerned that the damper force is not pure Y direction, you could also reverse those and have a constant downward force at the output and the damper at the cylinder.  Or you could just send the bottom attachment of the damper down significantly in Y.

 

SweetPeasHub_0-1696873746637.png

 

This seems simple enough but I believe this is a better answer to several similar questions in the community and it just popped into my mind today and I thought how dumb I was not to think of this yet!  😀  Thanks for reviving this question! I have Creo 10 models if you like a model.

9 replies

tbraxton
22-Sapphire II
Jul 6, 2021 2:54 PM UTC

Yes, it is possible. See the below link for the measures available in Mechansim. To investigate results in the time domain you will need to define a force motor to represent the hydraulic force applied as a function of time. This could be a constant force or vary with time.

 

https://support.ptc.com/help/creo/creo_pma/usascii/index.html#page/simulate/mech_des/measures/about_meas_results.html 

 

Application of a motor in Mechanism:

http://support.ptc.com/help/creo/creo_pma/usascii/index.html#page/simulate/mech_des/motors/To_Define_a_Motor.html 

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1-Visitor
Jul 7, 2021 10:21 AM UTC

Thank you for the fast reply @tbraxton 

Could you help me with some more details? I defined an force motor and rund an analysis. But which analysis ist the correct one? I think, that i need an dynamic analysis, because by using force balance i get only the force for one situation. Am I right with this? 

Which categorie do i chose, if i want to show the lever force in an Graph.

I would be very thankfull for any futher information.
Greeting 
Morian

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tbraxton
22-Sapphire II
Jul 7, 2021 11:37 AM UTC

If the results vary with time then you will use a Dynamic analysis. Without a free body diagram I am not clear on what you are trying to measure.

 

You can measure the reaction force at a mechanism connection or the net load on the force motor.

To Create Connection Reaction Measures (ptc.com)

 

 https://support.ptc.com/help/creo/creo_pma/usascii/index.html#page/simulate/mech_des/measures/net_load_measure.html 

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