Difficulty with band type brake

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Discussion Overview

The discussion revolves around a homework problem involving a band type brake, specifically focusing on calculating the brake torque and the force needed to stop a drum. Participants are examining the provided data, equations, and the implications of the geometry of the brake system.

Discussion Character

  • Homework-related

Main Points Raised

  • One participant presents the problem statement, including the maximum pressure, friction coefficient, and relevant equations for calculating brake torque and force.
  • Another participant suggests that the problem may be intended to be solved using the given geometry while neglecting the lifting of the band.
  • Some participants express concern that there may be missing information necessary to fully solve the problem, questioning whether any braking force would suffice to stop the drum if it is not being driven.
  • A later reply reiterates the concern about missing information, emphasizing that the data provided might not be sufficient for a complete solution.

Areas of Agreement / Disagreement

Participants generally agree that there may be missing information in the problem, but they do not reach a consensus on how to proceed with the calculations or the implications of the lifting band.

Contextual Notes

Limitations include potential missing assumptions regarding the geometry of the brake and the dynamics of the drum, as well as the dependence on the definitions of variables used in the equations.

torrgud
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Homework Statement


[/B]
What is the brake torque and the needed force to stop the drum.
Photo of problem: https://gyazo.com/5c814dc6791b29362cc2835dacf7005a
5c814dc6791b29362cc2835dacf7005a.png


Data not on photo: Max pressure is 0.7MPa and friction coefficient is 0.2.

Homework Equations


T=(P1-P2)D/2
p=2P/bD
dP-fdN=0
dN=Pdθ

The Attempt at a Solution


The only thing I've been able to do is use p=2P/bD and rearange it to get F=8.68N
I am unsure of what dθ is supposed to be since the band lifts up on a portion of the drum.
 
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This looks like a textbook problem, and I suspect that the intent is that you use the given geometry, neglecting any lifting of the band.
 
There seems to be some information missing? Any braking force will eventually stop the drum if it's not being driven.
 
CWatters said:
There seems to be some information missing? Any braking force will eventually stop the drum if it's not being driven.

This was all the data I was given in the problem. There might be some eqations I forgot but the data is all there, at least what the teacher put.