Contribution of air flow to impact attenuation in chamber structures

摘要: Head injuries are a major cause of morbidity and mortality worldwide, many resulting from sporting activities. Currently, there is need in the head protection industry for improved technology capable reducing risk mild severe injuries. Contemporary devices comprised mainly foam have several inherent disadvantages, including limited ability to provide effective energy absorption under both low high impact velocities. New thin-walled collapsible chamber systems may resolve this problem. The chambers consist four engineering elements which alter their performance geometry, air volume, material, venting system. This research analyzed contribution flow through an orifice chamber's management energy. main objective study was determine effect vent diameter on peak force rate during impact. Two material stiffnesses five diameters were tested at three inbound Each impacted ten times using monorail drop Significant effects found stiffness, diameter, velocity (pO.OOOl). Under velocities largest transmitted less than smallest, while relationship reversed negatively, duration positively correlated force. velocities, positively, negatively suggested that performed optimally when dissipated fast, short duration; however, as approached critical failure region, increased decreased released prevented larger forces. Overall, confirmed engineered thinwalled use mechanism absorb impacting