Optimization and experimental investigation of additively manufactured sandwich structures under blast loading

This study investigates the design and performance of steel sandwich structures with cellular lattice cores featuring bi-linear density gradients. Several lattice topologies are examined as potential candidates for the core configuration. A comprehensive design procedure is proposed, including the selection of cellular topologies, analytical pre-dimensioning, and detailed surrogate-based optimization. The optimization framework integrates a neural network, a genetic algorithm, and an adaptive sampling strategy to efficiently explore the design space based on automated finite element simulations. Key design variables, including the relative density and density gradient of the lattice structure, are studied across different lattice unit cell configurations, with the objective of minimizing the maximum transmitted force. To validate the optimized designs, sandwich structures with various lattice topologies and density gradients are manufactured via laser powder bed fusion using 30CrMoNb5-2 steel alloy as base material. Their dynamic resistance is experimentally evaluated in an explosive-driven shock tube. The findings demonstrate the potential of advanced lattice core design and additive manufacturing to enhance blast protection performance.