Flexible materials and structures for mitigating combined blast and fragment loadings–A review

Flexible materials and structures, mainly including nonmetallic and nonceramic materials, are being increasingly applied in the field of blast mitigation to prevent collateral damage by secondary debris. This paper outlines the load characteristics of typical explosions and the modern trend of using flexible materials and structures for blast mitigation. An attempt is made to interpret blast waves, fragments, and their combined load characteristics and discuss the loading and testing methods used at different explosion scales. The findings can help develop tailored approaches for property evaluation and optimized designs of flexible materials and structures according to specific loadings. The protective mechanisms of flexible materials such as water, foam, fiber and polyurea under different loadings are analyzed, and their differences in efficacy and application advantages are summarized. Furthermore, the blast mitigation properties of composite structures (graded, auxetic, and sandwich structures) composed of flexible materials are discussed in detail. Especially for protection from combined loading, the decoupling method of structure ordering based on load sequence improves protection efficiency. This study facilitates the selection of flexible materials, structural design methods and performance evaluation criteria for mitigation of combined blast loading, and it provides a platform for developing flexible structures with great functional designability in the fields of rapid disposal of explosives and protection of high-value targets.