Helmets are widely used in sports activities, known as a bicycle helmet, mountain off-road helmets, skating helmets, ski helmets, rock climbing, helmet, etc., these helmets, its main
function is in the people in the sports activities after a fall can be useful in preventing injuries of the head, the working principle of safety helmet is commonly when unexpected
attack, and when the head hit the pavement, On the one hand, with its slick appearance, the impact will be taken forward, reducing the time the force stays on
the head, and then reducing the damage to the head and brain may be suffered. Visible safety helmet on market now, its structure is roughly same, all is in the cap is equipped with
buffer layer in the crust; but because of the different production art, there exists a big difference, the role of practical use such as glue is to buffer layer
adhesion to cap shell, simple in the process of adhesive in the cap shell with gaps between buffer layer, results in the decrease of practical seismic cushion, It can even affect the safety of
athletes.