Analysis of the Significance of Helmets in Football Head Collisions

Introduction

Football helmets are designed to protect the skull against bruising and fracture during linear impacts. The two key aspects that allow the helmet to do this is by slowing down acceleration and distributing the force over a larger area. The acceleration is reduced through deformation of the outer shell and liner of the helmet that spreads the force throughout the helmet [1]. A study using intraoral measurements of peak acceleration found that the peak acceleration is 50% less when wearing a helmet [2]. Additionally, it was found that without a helmet the area of the skull receiving the blow is about 5 square inches, whereas when wearing a helmet the same force is distributed over an area of about 50 square inches [3].

In order to show the significance of the football helmet in head collisions, I performed a finite element analysis on the skull using Scan&Solve Pro. The human skull model was obtained from GrabCAD and contained a total of 50 meshes, 252376 vertices, and 352792 polygons. The complexity of the geometry of this model makes Scan&Solve ideal for this study because it supports assemblies and doesn’t require the model to be converted to a finite element mesh.

Scan&Solve Pro Setup

The values for mass and acceleration of a helmet to helmet football collision were found using a previous study[4] and the resulting force value was calculated (see Table 1 above). For the simulation run without the helmet the acceleration was doubled and the area that the force was distributed over was increased by about a factor of 10.

Results

Conclusion

The results from the finite element analysis using Scan&Solve Pro shows the effect that a helmet has on head collisions in football. The max total displacement of the skull and the max von mises stress on the skull were both significantly reduced by the helmet. This reduction in displacement and stress shows how a helmet protects the skull from bruising and fracture during linear impacts.

References

[1] Michael Higgins, D. (2018). Measurement of Impact Acceleration: Mouthpiece Accelerometer Versus Helmet Accelerometer. [online] PubMed Central (PMC).

[2] Lewis, L., Naunheim, R., Standeven, J., Lauryssen, C., Richter, C. and Jeffords, B. (2001). Do Football Helmets Reduce Acceleration of Impact in Blunt Head Injuries?. Academic Emergency Medicine, 8(6), pp.604-609.

[3] Andersen, M. (2005). The physics of how a helmet works. [online]
[4] Hoshizaki, T., Post, A., Oeur, R. and Brien, S. (2014). Current and Future Concepts in Helmet and Sports Injury Prevention. Neurosurgery, 75, pp.S136-S148.