Concussion question regarding PSI for football helmets

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Discussion Overview

The discussion revolves around estimating the pressure in pounds per square inch (psi) on a football helmet that correlates with the g-forces (70 to 120 g) associated with concussions. Participants explore the relationship between impact forces, pressure, and the dynamics of head acceleration during impacts.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant questions whether it is possible to estimate the psi on the helmet corresponding to 70 to 120 g forces.
  • Another participant asserts that the more critical quantity to consider is "impulse," suggesting that it may provide a different perspective on the problem.
  • A participant calculates that if the head has a mass of 7 kg and a cross-sectional area of 0.03 square meters, the pressure at 120 g would be approximately 274 kPa.
  • There is a suggestion that the dynamics of the entire body, including acceleration and rotation, may complicate the relationship between head acceleration and the resulting forces experienced.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the feasibility of estimating psi from g-forces, with some expressing skepticism and others providing calculations and alternative considerations.

Contextual Notes

Participants note the complexity of the problem due to the involvement of the entire body during impacts, which may affect the forces experienced by the head. There is also mention of the importance of understanding impulse in this context.

tmh556
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Hi, I have a bit of a random question which is a little apples to oranges. I saw that concussions on the human brain are caused at roughly 70 to 120 g forces as measured from sensors placed on a football helmet:

https://www.google.com/search?q=bar...nt=gws-wiz#kpvalbx=_tn49Y8j2J76jz7sP8d2o8AU_4 My question is...is there a way to figure out the psi (pounds per square inch) on the helmet that causes this 70 to 120 gs. Is there a way to infer this or roughly estimate this number? Any help would be greatly appreciated! Thanks, Tom
 
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Usually when we get impact questions we are stymied by not knowing the acceleration. Here we have it, so I don't see why it can't be answered. If the head is 7 kg and has a cross sectional area of 0.03 sq meters, at 120g the pressure is 274 kPa.
 
russ_watters said:
Usually when we get impact questions we are stymied by not knowing the acceleration. Here we have it, so I don't see why it can't be answered. If the head is 7 kg and has a cross sectional area of 0.03 sq meters, at 120g the pressure is 274 kPa.
I would suspect the issue is with the remainder of the body attached to the head (hopefully :-p ). It is going to accelerate and rotate from the force along with the head. That should increase the force for a given “head” acceleration.

 
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