Research: Human brains can be injured by impact or by exceptionally violent rotation of the head, when the brain remains stationary. Internal blood vessels and nerves yank parts of the brain around in different ways, straining the vessels and nerves in the process.
Helmets designed to handle major crash energy generally contain a layer of crushable foam. When you crash and hit a hard surface, the foam part of a helmet crushes, controlling the crash energy and extending your head's stopping time by about six thousandths of a second (6 ms) to reduce the peak impact to the brain. Rotational forces and internal strains are likely to be reduced by the crushing. Thick plastic foam (firm polystyrene) inside the hard outer shell of a helmet provides protection that cushions the blow.
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.
Standards define laboratory tests for helmets that are matched to the use intended. If a helmet can pass the tests for a sport or activity, it provides adequate impact protection. A construction helmet will not pass the more severe bicycle helmet tests. A bicycle helmet will not pass the more severe motorcycle helmet tests. None of them provides the protection against shrapnel that is required of a military helmet.
My Helmet:
The helmet I 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 made of hard plastic like I mentioned before. This helmet contains a features that lead to outstanding results. Carbon fiber mesh surrounds the head and an overhead that protects the eyes of the drive. from the sun. The back end of the helmet is a good shape for a human head, the straight back of my helmet provides good posture and accessibility of your neck to not feel so restricted.