Theoretical and numerical investigation of blast responses of continuous-density graded cellular materials

The blast responses of one-dimensional continuous-density graded cellular bars are investigated theoretically and numerically. A theoretical model is developed based on the rigid-perfectly plastic-locking (R-PP-L) model, and finite element (FE) analysis is performed using the random Voronoi technique. The FE results agree well with the analytical predictions. The blast response and energy absorption of the cellular bar with the same mass are examined under different blast loading and cellular gradients. The cellular structure with high energy absorption and low impulse transmit is appropriate for protecting impacting objects because it can satisfy the crashworthiness requirements. However, energy absorption and impulse transfer are two conflicting objectives for blast resistance capability in cellular materials with different gradient distributions and variations. The capacity for energy absorption increases with blast loading because of intensified dynamic plateau stress and crushed displacement under increased blast pressure. By contrast, the transmitted stress is enhanced when blast loading exceeds the resistance capacity. Results of this study would improve our understanding of the performance and mechanisms of continuous-density graded cellular materials under blast loading and provide a guideline for structural design.