Design and optimization of bio-inspired thin-walled structures for energy absorption applications

Thin-walled structures are widely used in the automobile, aerospace, and other engineering disciplines for impact energy absorption purposes for their lightweight and high energy absorption capacities. In this study, the energy absorption characteristics of various designs of the bionic structures inspired from bamboo are investigated so that the optimum design with the highest energy absorption can be achieved. For high-velocity impact applications (100 m/s), a rate-dependent material model is employed in all analyzes. Different design-cases with various connecting ribs are studied, and the optimum number of connecting ribs is obtained for each design-case. For the best performing designs, design parameters are optimized using Non-Sorting Genetic Algorithm 2 (NSGA2) to enhance the energy absorption properties further, yielding a 17% increase in the energy absorption capacity. Finally, for a more popular number of ribs, i.e. 4 and 6, design parameters are optimized using NSGA2 for practical applications. It is shown that it is crucial to employ a rate-dependent material model in the impact modeling as the results are highly reliant on the dynamic behavior of the material.