Vehicle Hull Shape Optimization for Minimum Weight Under Blast Loading

Abstract : Shape structural optimization for blast mitigation seeks to counteract the damaging effects of an impulsive threat on occupants and critical components. The purpose of a vehicle energy-deflecting hull is to mitigate blast energies by channeling blast products and high-pressure fluids away from the target structure. Designs of pyramid‐shaped protective structures have been proposed in existing and concept vehicle's platforms. These structures are more effective than the traditional flat-plate designs in terms of cabin penetration and weight. Studies on other blast concept design remain scarce. This investigation addresses the design of blast‐protective structures from the design optimization perspective. The design problem is stated as to finding the optimum shape of the protective shell of minimum mass satisfying a deformation and envelops constraints. Performance improvements are observed as the envelope constraint is relaxed and the optimization problem includes a larger number of design variables with the consequent computational cost. In order to consider the solution of a problem with no envelope constraints, this work explores heuristic alternatives: inverted profile and hybrid cellular automata (HCA). Numerical results demonstrate that convergent designs based on trigonometric functions yielded a greater reduction in mass over baseline than all other candidate designs, and show promise for future development. Designs generated via the HCA topography method resulted in structures whose performance paralleled or exceeded most geometrically constrained designs despite the fact that they can be created with fewer computational resources and adapted to irregular design domains.