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1-Visitor
July 6, 2021
Solved

How to messure Leverage, Leverforce in Creo Mechanism

  • July 6, 2021
  • 1 reply
  • 6339 views

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

Best answer by SweetPeasHub

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.

1 reply

tbraxton
22-Sapphire II
22-Sapphire II
July 6, 2021

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 

1-Visitor
July 7, 2021

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

tbraxton
22-Sapphire II
22-Sapphire II
July 7, 2021

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