studio vibrazioni

[PaoloAR]

Bye to all,
I would like to get a frame of an industrial machine (simplified) as vibrating after moving a cart that runs on a guide. What kind of analysis is needed? (I know the motorcycle law of the cart)
Thank you.

 

[Fulvio Romano]

It is not clear if you want to simulate vibration or if you want to measure it on an existing frame.
it is not clear to what purpose you want to do this analysis (fatigue, safety at work, bolt locking, etc.)

 

[PaoloAR]

I was for granted, as it is the part of the forum "ansys", it was understood that the goal would be to simulate (fem) the dynamic behavior of an indutrial machine. the end (intermediate) is to have a fem model validated by experimental data in terms of vibration amplitude.

 

[Fulvio Romano]

I was for granted, as it is the part of the forum "ansys", it was understood that the goal would be to simulate (fem) the dynamic behavior of an indutrial machine. the end (intermediate) is to have a fem model validated by experimental data in terms of vibration amplitude.

It was clear. Just seeing the forum from the mobile phone I lost the section. Sorry.

 

[lucadileta]

Is the discussion still active?

sent by my sm-n950f using tapatalk

 

[PaoloAR]

Is the discussion still active?

sent by my sm-n950f using tapatalk

Yeah.

 

[Stan9411]

quite complex as a problem.
in any case it is not clear if:
- the cart moves of harmonic motion along the machine with a specific frequency;
- what you want to measure. “as vibration” is very generic.

waiting for your clarifications, I would tell you to find the proper frequencies of your machine and verify that they do not coincide with the frequency with which the cart moves. so at least you try to be away from resonances.
then maybe something better comes to mind.

(eye that with the fem discusses reality. in the modal analysis the goodness of discretization affects very much the results. if your structure is a “frame” I recommend you to model it as beam to lighten the calculation otherwise do night)

 

[PaoloAR]

quite complex as a problem.
in any case it is not clear if:
- the cart moves of harmonic motion along the machine with a specific frequency;
- what you want to measure. “as vibration” is very generic.

waiting for your clarifications, I would tell you to find the proper frequencies of your machine and verify that they do not coincide with the frequency with which the cart moves. so at least you try to be away from resonances.
then maybe something better comes to mind.

(eye that with the fem discusses reality. in the modal analysis the goodness of discretization affects very much the results. if your structure is a “frame” I recommend you to model it as beam to lighten the calculation otherwise do night)

thank you for the answer.
in short, simplifying, seeing the frame from the front, I have the pick and place that from about the central part, moves to the left, then lowers (the lowering of the head I would not have at the moment implemented) brings the product all to the right, gets up and back in central position. is a complex industrial and large machinery.
the end would be to decrease as much as possible the vibrations of the machinery.
all movements are very segmented, with intermediate breaks and vibrations make in time to damp so in practice (to the eye but I think it corresponds to reality) the own frequencies are never excited (or at least for prolonged periods) and there should be no resonance problems.
to do, in practice, the merge between rod elements and not rod that command is used?

 

[Stan9411]

if I have understood the problem then is that the end effector, moving suddenly from a position to the next produces a kind of impulse that is reflected as vibrations on the structure. the problem is very complex, because it also depends on the elasticity of the connection between end effector and frame (straps, ball recirculation guides) which is very difficult to estimate but heavily influences the transfer function between your cart and the structure. you can improve the behavior by acting on the motor motorcycle law, trying to have a softer deceleration phase.

 

[Stan9411]

about the question “technical” of ansys unfortunately I cannot answer

 

[PaoloAR]

if I have understood the problem then is that the end effector, moving suddenly from a position to the next produces a kind of impulse that is reflected as vibrations on the structure. the problem is very complex, because it also depends on the elasticity of the connection between end effector and frame (straps, ball recirculation guides) which is very difficult to estimate but heavily influences the transfer function between your cart and the structure. you can improve the behavior by acting on the motor motorcycle law, trying to have a softer deceleration phase.

You basically got the point.
I would like to simulate everything on ansys and from there see for example where to change frame, motion law, and/or consequently changes on engines. I would like to treat it on a vibrational field more than a bovine construction of machines (if possible).

 

[Stan9411]

if the trolley from “impulses” to your frame, it means that for a short period your frame will be excited at every frequency, since the spectrum of an impulse is ideally constant at every frequency. I would tell you to statically dimension your frame, then focus on damping the vibrations of your only end effector (actively acting on engines).

 

[PaoloAR]

if the trolley from “impulses” to your frame, it means that for a short period your frame will be excited at every frequency, since the spectrum of an impulse is ideally constant at every frequency. I would tell you to statically dimension your frame, then focus on damping the vibrations of your only end effector (actively acting on engines).

therefore from simulation the only first part "static" and instead more experimental damping changing the laws of motion?