Conventional helmets lack a corresponding fixation on the head and on the sides. In addition, the lower parts of the head are not protected, which leads to a significant safety deficit. Based on bionic principle, a prototype will be developed to solve these deficiencies.
Three main parts of the helmet are to be modified: the outer hard shell of the helmet, the protection of the lower head part and the damping material on the inside of the helmets. Insights from the study of insects are used to optimize the outer hard shell and maintain the protection of the lower part of the head.
Insects have an exoskeleton built of cuticle, which covers the entire animal. To make the exoskeleton functional for numerous different mechanical purposes, the cuticle is modulated in two ways: (1) areas of the cuticle are either flexible or hardened to a varied extent; (2) parts of the cuticle are folded or bulged to the inside, outside or are thickened.
One functional ensemble is the pair of mandibles, which are strong projections hanging downward from the head capsule of the insect. The mandibles perform a transverse swinging motion (towards the middle and sideward). They abut to the head capsule through two ball-and-socket articulations (anterior and posterior), which stabilize the swinging motion by providing a fixed axis of rotation. The head capsule is provided with internal ridges, which minimize the deformation of the capsule during the forceful movement of the mandibles.
The mandibles and internal ridges of the head capsule are used to optimize the helmet shell. Collagen, the main component of cartilage, is used as a natural bionic damping material embedded in a polymer matrix.
Different designs are developed and virtually tested using the Finite Element Method (FEM). Combination and design of different materials determine the performance significantly. Therefor the used materials must be characterized and the material behavior has to be represented within FEM models. This enables for a time and cost-effective digital development and a quantitative comparison. The most promising virtually tested prototypes are then manufactured using fused deposition modeling (FDM) and tested physically. This serves to check the possible series suitability of the bio-inspired helmets.