An instrumented head system has been constructed using a Hybrid III headform mounted on a Eurosid neck unit. A tri-axial array of nine linear accelerometers was used to enable measurements to be made of both the linear and angular accelerations experienced by the headform during impacts from a variety of missiles designed to replicate the real-life threats experienced by police officers in the course of their duties. The design, construction and validation of the system are described. The results for different helmets are presented, discussed, and compared with other published work in related areas. It has been demonstrated that: (1) very high peak angular accelerations (more than 10,000 radians/s (super 2)) can occur with relatively low peak linear accelerations (120 'g'); (2) the short duration of the acceleration results in low angular velocities (25 radians/s); and (3) the peak acceleration and velocity values vary as a function of the impact energy and impact momentum for different types of helmet. (A)
Abstract