چكيده به لاتين
Owing to the fact that the human head is most likely to be injured in an accident, therefore, it is important to protect it against impact loads, because evidences and statistics showing that the most important cause of death in road accidents was a head injury, and due to this case there have been seen many deaths. A helmet is one of the tools that reduces the severity of injuries to the motorcyclist in the head during an accident. The helmet minimizes its severity of impact after dealing with hard objects, such as land or cars.
The purpose of this study is to compare the resistance impact of a helmet for three different kind of energy-absorbents (EPS, XPS, MAC), and then choose the best materials, and compared the resistance of the material in the layers of different thicknesses, and finally, determined the optimized thickness with considering of weight, impact resistance, and manufacturing cost. Different modes of combining these three materials were also tested and the results were recorded. The results showed that the expanded polystyrene material performs better than the other two materials in terms of resistance. Additionally, in terms of cost, it is cheaper than the other two materials. However, because the energy absorption property of this material is greatly reduced in the second impact afterward, it must either replace another material or use composites to improve this weakness.
Keywords: Helmet, impact, Energy-adsorbent, Manufacturing cost, Thickness.