Chronic Traumatic Encephalopathy (CTE) Limiting Sports Helmet​

Overview

Chronic Traumatic Encephalopathy (CTE) is a neurodegenerative disease with various symptoms including memory loss, aggression, depression, and suicidality among many others. It’s caused by repetitive blows to the head which accelerate the skull and cumulatively build up, damaging the brain tissue. This is common in football players as they endure many impacts during the long seasons. Therefore, the goal of our project is to design an air bladder system helmet that will reduce the acceleration of the head during every impact to reduce the occurrence of CTE.  

Objectives

The three main goals for the project are as follows:
– Research CTE occurrence as it relates to head impacts in football players, as well as real-time recorded head acceleration data during games and practices.

– Construct a model of the head and helmet system to run simulations as a function of initial velocity, head mass, and bladder size.

– Create an experimental prototype of the helmet system which can be tested to obtain acceleration data.

Approach

– The team was provided with the patent for the helmet system from sponsor Dr. Jeffrey Shakespeare of Product Realization Specialties, LLC.

– A patent search was conducted to make the team aware of other existing products.

– Literature searches were conducted to understand CTE occurrence and obtain real-time recorded head acceleration data during games and practices which were used to quantify design requirements.

– Surveys were sent to current/former football players and football fans to understand customer needs.

– Seven design requirements were identified: minimize head acceleration, re-inflatable bladders, durability, minimize weight, look like a football helmet, custom fit, and minimize cost.

– The team created three iterations of prototypes with the final iteration consisting of a helmet shell, latex air bladder, open cell foam inside the air bladder to aid in the reinflation process, and an aluminum machined valve.

– The team machined a custom aluminum valve with different sized tapped holes that could be opened or closed (using set screws) to test which opening minimized head acceleration.

– The team built an 8-foot-tall testing rig to conduct consistent drop tests using an accelerometer to record the acceleration during the impact.

– A model was created in MATLAB to simulate the dynamics of a helmet drop test which outputs the position, velocity, and acceleration of the head over time as a function of the drop height or initial velocity, head mass, and bladder size.

– Drop tests were conducted 5 times at each drop height for each the original padding, valve completely closed, and various number of holes opened, and the peak acceleration was averaged over the 5 drops.

– We found that the optimal valve size was one #6-32 hole (diameter ~ 0.138”) as it reduced the average peak head acceleration by 16 g’s compared to the original padding.

Outcomes

– The sponsor will be able to continue improving the helmet system by using our testing results to implement a microcontroller with an algorithm to dynamically open and close the valves.

– The air bladder system can reduce head acceleration by 36% compared to the original padding of the Riddell Speed helmet.