Paper Title
The Study on Application of Rubber Sponges for Impact Absorber for Motorcycle Helmets

This study was aimed to evaluate the potentials of applying low-price natural latex for producing rubber sponges as an impact absorber in motorcycle helmets. Three types of commercial motorcycle helmet: shorty, open-face and full-face were used in this study. The rubber sponges of 1 cm and 1.6 cm thickness were produced and adhered to the comfort foam inside the helmets and were tested through two series of tests: impact tests and drop tests. For the impact tests, a 2-meter liftable hammer was dropped and stroked on the experimental helmets. The load response of specimens were recorded. The value of peak accelerations and Head Injury Criterion (HIC) were the main parameters focused in this study. It was found that the helmet with rubber sponges can lower peak load of helmet between 34 – 53 % for 1-cm thickness and between 40 – 64.7 % for 1.6 cm thickness. The rubber sponges can also reduce the value of HIC of commercial helmet, maximum by half for shorty. In addition, acceleration of helmet can be also reduced by applying rubber sponge to the comfort foam. It could be concluded, based on those parameters, that the rubber sponge layer adhered to comfort foam inside the helmet can improve the impact capacity of motorcycle helmets. Many criterions that are linked to severity of head and brain injured were reduced significantly. This implies that the rubber sponge is potentially to be used as impact absorber for motorcycle helmets. Keywords - Helmet, Impact, Rubber Sponge, Energy Absorption