Design optimization for 3D printed energy absorbing structures inspired by nature

Abstract

Transportation is a major part of people’s every day life in today’s society allowing them to get to their jobs, commute, trade, travel etc. Motorcyclists and cyclists are among the most vulnerable road users and in case of an accident, they are highly dependent on bearing a helmet to protect against severe damage. Studies have shown that bearing a modern helmet provides 63% to 88% reduction of sustained head and severe brain injury in case of an accident for bicyclist. A route to further improve helmets, besides developing stiffer and tougher materials, is to develop a helmet that also relies on the material structure, i.e. its inner geometry and architecture, for energy absorption. Additive manufacturing or 3D printing allows three-dimensional objects or components to be manufactured with a complexity which would be difficult or near impossible to realize with today’s conventional manufacturing techniques used for helmets. With the possibilities and precision 3D printing enables in mind, structures based on geometries found in nature is investigated and theoretically optimized to absorb as much energy as possible on impact meanwhile keeping the mass low. Three main structures made up of beam elements were chosen and further investigated in a script. The script is designed to generate and optimize the structure by positioning its elements and varying their position, width, height and radius and evaluate it regarding specific energy absorption by doing a FEM analysis and a buckling analysis. Ultimately the script work as intended by successfully generate the sought structures and autonomously update the structures variables and return an optimized combination of the variables which maximized the structures ability to absorb energy on impact. Keywords: Beam, helmet, energy absorption, 3D printing, optimization