Fitness Evaluation of Military Helmet Pad

Military helmets are designed specifically to protect soldiers’ heads during combat. Poor helmet fit has been reported to decrease the helmet’s comfort and the ability to provide safety protection. To increase the safety and comfort of soldiers wearing military helmets, the head size and pad design should be considered. Thus, the aim of this study is to evaluate the proper thickness of pad design for fit and comfort of military helmets. A total of 20 male participants were recruited in this study. A digital caliper and three-dimensional (3D) head scanner were used to measure participants’ helmet standoff distance (SOD) with two pad thickness levels (10 and 20 mm) placed in the same helmet shell. A 3D head-scanning system was used to obtain the 3D head shape model and to measure the head dimensions. The CATIA software was used to calculate the SOD between the 3D head-scanning model and the military helmet to assess helmet fit. The SOD results showed that the contact pressures for the two pad thicknesses were significantly different in five regions. The pad with a thickness of 10-mm had less contact pressure. Thus, the pad with a thickness of 10-mm is recommended because it can provide better fit and comfort for a military helmet. The findings of this study provide useful references for designing and developing head-related products in the future.