Crashworthiness optimization of honeycomb structures under out-of-plane impact using radial basis functions

Crashworthiness design and development of lightweight structures have become important engineering challenges because of the high standards of energy consumption and safety regulations. Within this context, the use of honeycomb structures as crush absorber is continuously growing in automotive and aircraft industries, once honeycombs are known for their high strength-to-weight ratio and excellent energy absorbing capacity. Thus, this paper presents a method that combines radial basis functions with expected improvement to optimize the specific energy absorption of honeycomb cellular materials, while the peak crush force is constrained at low levels for safety reasons. Honeycomb's cell size, cell shape and thickness are the design variables. Concerning the cell shape, the results indicate the hexagonal configuration has a higher out-of-plane performance compared to auxetic and rectangular cells in terms of energy absorption capacity. Lastly, a multi-objective optimization using only the radial basis function predictor (without sequential sampling) is carried out to seek simultaneously for optimal solutions with minimum peak force and maximum specific energy absorption.