The function of a bicycle helmet is to protect the rider's head in case of an accident. The head is the most important part of the body, and, in a way, the most susceptible to injury as it is the last part of the body to hit the ground in a crash. There are many tests a helmet must pass to be deemed safe. The perepheral vision test, for example tests to make sure that the helmet does not block the users view in any way. The positional stability test ensures that the helmet will not fall off in the even of a crash. The retention test tests to show that the straps are not too long to make the helmet fall off. And the impact attuention test, the helmet is tested to see if it actually lessens the damage to a person's head in a crash. Helmets typically contain an interior lining, often made of crushable foam. The liner of a helmet performs two functions: to redistribute the force over a larger area, and to set an upper limit to the level of the distributed force. The maximum level of tolerable deceleration to the human head (a) is 300 g, and the mass of a head (m) is approximately 3 kg, so the maximum allowable force equation is F=m k=9kN. As the liner crushes between the skull and the surface, it distributes the force over the area (A). To prevent the force from rising above 9 kN, the liner must crush with force at sc(0.25) = F/A = 0.9 MPa. Helmets must have a strong outer layer. This helps the helmet not break apart or crack in a crash and defends against sliding. The inside of a helmet is usually made of styrofoam or another material. I serves the purpose of shock protection and comfort.
Our Design
Our Helmet
The bicycle helmet we have created theoretically fits all of the Helmet Safety Standards. It would not block the rider’s vision (Peripheral Vision Test), it would not fall off of the rider’s head in the case of an accident (Positional Stability Test), it passes the Retention Strength Test because it is designed with an alternative to loose straps, and it passes the Impact Attenuation Test because it significantly lessens the impact to the rider’s head in the case of an accident. A helmet is considered safe if it passes an acceleration drop test of 2 meters at 14 miles per hour. Theoretically, if we subjected our helmet to these tests, it would pass. We decided to use a new state of the art core material called “Koroyd” which can be 3D printed to cover 90% of the user’s head. Koroyd is a material that serves as the crumple zone of the helmet. This creates a cushion for impact crashes.The Koroyd material yields a low coefficient of friction, which minimizes the impact of force on the skull. We will cover the Koroyd with a layer of carbon fiber material. Carbon fiber forms a strong barrier on the helmet for crashes producing kinetic friction that involve scraping and sliding. This helmet contains a couple unique features that lead to outstanding results. The carbon fiber mesh extends out over the user’s eyes to form a visor. This protects the rider from the sun, falling rocks, and branches from foliage. The back end of the helmet extends slightly down the riders back, this optimizes the aerodynamic function of the helmet, and provides back support in the case of a crash.