What Are the Reactions at the Occipital Condyles in a Head Impact Analysis?

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SUMMARY

The discussion focuses on the analysis of forces acting on the occipital condyles during a head impact scenario. The scenario involves a head modeled as a rigid body subjected to an axial force, shear force, and neck torque, with a specific emphasis on a chin impact at a 63-degree angle. The initial linear acceleration is determined to be 140 times gravity for a head mass of 3.5 kg and a moment of inertia of 0.0356 kgm². The participant concludes that neglecting torque simplifies the analysis, suggesting that moment of inertia may not be necessary for calculating the reaction forces at the occipital condyles, arriving at an estimated reaction force of approximately 9500 N.

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  • Understanding of rigid body dynamics
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  • Knowledge of basic mechanics, including forces and torques
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  • Research the application of the parallel axis theorem in rigid body dynamics
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This discussion is beneficial for mechanical engineers, biomechanics researchers, and students studying dynamics, particularly those interested in head impact analysis and injury mechanics.

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I have a Force Acceleration analysis that I am un sure of. I have a picture of a skull that is punched/kicked/whatever in the chin.

Problem Statement:

The head shown in the figure below is considered a rigid body. IT rocks on the occipital condyle, C, where an axial force, Fa, and a shear force, V, and a neck torque, To, resist the motion. A blow is applied to the chin at point B at an angle of 63 degrees relative to the horizontal. The initial linear acceleration, a, of the mass center, G, is photographically deteremined to be 140 x gravity. For a head of mass 3.5kg, a moment of inertia of 0.0356 kgm^2 about an axis perpendicular to the sagittal plane is calculate.d WHat are the reactions at the occipital condyles if torque To is neglected?


Ive used the parallel axis theorem to find my actual needed inertia.

I am thinking that maybe I need to do a sum of moments about the condyle to find a reaction force, but I'm not sure if that is right or how to do it. I can't figure out how to incoroporate the moment of inertia.

If anyone can help shed some light for me, I would appreciate it.

I will also be around to answer any questions one might have.

Thanks a bunch.
 
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After doing some research, I have come to the conclusion that if i neglect torque, then I don't even need to worry about moment of inertia. Is this correct? I can't find any equation that relates linear motion with moment of inertia unless there is torque involved.

Is this correct?
 
You may want to put an image on the web, since I don't see any included in your post. Until then, no one will probably be able to help you. :smile:
 
Here is an attachment of what my assignment is.
 

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The answer I came up with is about 9500 N. Is this possible?
 

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