Dynamic balancing without static balancing

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Discussion Overview

The discussion revolves around the concepts of dynamic and static balancing, particularly in the context of rotational systems. Participants explore whether it is theoretically possible to achieve dynamic balancing without static balancing, raising questions about the relationship between the center of gravity and the axis of rotation.

Discussion Character

  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant defines static balancing as having the center of gravity aligned with the axis of rotation, while dynamic balancing is described as having the principal axis of inertia parallel and coincident with the axis of rotation.
  • The same participant questions if dynamic balancing can exist without static balancing, suggesting a scenario where the center of gravity is outside the axis of rotation but the principal axis remains aligned.
  • Another participant shares an experience with car tires, noting that dynamic balancing tends to provide better performance, particularly at higher speeds, and mentions issues with static balancing leading to vibrations at resonant frequencies.
  • A later reply asserts that the principal axes of inertia must pass through the center of mass, implying that dynamic balancing without static balancing is not possible.

Areas of Agreement / Disagreement

Participants express differing views on the possibility of achieving dynamic balancing without static balancing, with some arguing it is feasible under certain conditions, while others contend it is not possible based on definitions of the principal axes of inertia.

Contextual Notes

The discussion includes assumptions about the definitions of static and dynamic balancing, as well as the relationship between the center of mass and the principal axes of inertia, which may not be universally agreed upon.

hazar
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static balancing is when the center of gravity is in the axis of rotation.

dynamic balancing is when the central principal axis of inertia is parallel and coincident with the axis of rotation.

my question is, even if its theoretically, can you have dynamic balancing without static balancing?

If you have the center of gravity outside the axis of rotation but still have the central principal axis of rotation on and parallel with the axis of rotation, do you not have dynamic without static balancing?
 
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From experience with car tires, it seems that dynamic balancing is always better. If you statically balance the tires then at some certain speeds you'll get a wobbly feeling due to hitting the resonant frequency.
 
jedishrfu said:
From experience with car tires, it seems that dynamic balancing is always better. If you statically balance the tires then at some certain speeds you'll get a wobbly feeling due to hitting the resonant frequency.

Thanks but still doesn't answer my question in a way.

Can you have dynamic without static
 
The principal axes of inertia pass through the center of mass, by definition.

So the answer to your original question is no, you can't have the principal axis along the axis of rotation but the center of mass somewhere else.
 

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