Calculating Inertia for Changing Speed Engines Connecting Rod

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    Formula Inertia
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Discussion Overview

The discussion centers around calculating the inertia of an engine's connecting rod that experiences changing speeds. Participants explore different formulas and concepts related to inertia, energy, and their relationship to speed changes.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant notes the existence of different formulas for inertia, suggesting that they may pertain to different types of inertia.
  • Another participant asserts that if the connecting rod is treated as a rigid body, the moment of inertia (MMOI) remains constant and is unaffected by changing speeds.
  • A different viewpoint introduces the kinetic energy formula, suggesting that it may be relevant to the discussion of inertia in the context of changing speeds.
  • One participant emphasizes the distinction between energy and inertia, indicating that clarity on the specific need is essential for further assistance.
  • Another participant expresses concern that without a clear understanding of the requirements, it will be challenging for others to provide help.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the specific formula or concept needed for calculating inertia in this context. Multiple competing views remain regarding the relationship between inertia, energy, and changing speeds.

Contextual Notes

There are limitations in the discussion regarding the assumptions made about the connecting rod's behavior and the definitions of inertia and energy being used. The relevance of velocity to the inertia calculation remains unresolved.

jaguar57
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Calculating for a section of an engines connecting rod that is always changing speed
I have seen different formulas for inertia. Must be different types.
Since it is changing speed I guess I am looking for the inertia that is against that change.
any help is much appreciated. I know ya'll get a lot of questions on this forum.
 
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Assuming that you are treating the con rod as a rigid body, the MMOI is simply a constant, the integral of r^2 dm. Changing speed has no impact on the MMOI value.
 
I think maybe the formula I need is the one that includes velocity which is
KE= .5 x kg x velocity^2
 
Energy an inertia are different things. We can't tell what you need.
 
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If you don't know what you need, it will be very difficult for anyone else to help you because we don't know either.
 

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