Mitigating Damage of Structures Under Blast Loads Using Linear Protective Layers

The response of structures to blast loads commonly includes damage that cannot be avoided. The trivial method to enhance the structural resistance under blast loads is by stiffening its cross-section, which may lead to an uneconomical design regarding material weight and cost. An alternative method is to use sacrificial layers placed on the surface exposed to the blast loads and designed so that the damage will be redirected and concentrated on them, not on the main structure. After loading, the main structure experiences minimal damage, and the sacrificial layer can be replaced easily. Sacrificial layers commonly include voids, and during the dynamic response, the voids are closed, the damage is developed in the layers, energy is absorbed, and effective lower pressure is transmitted to the structure. With inspiration of sacrificial layers, this study suggests using linear protective layers (LPLs) instead of sacrificial layers, i.e., layers that will not experience any damage and are characterized by linear stiffness. This can be, for example, a plate connected by linear springs to the structure. Because they are linear, the load that is transmitted to the structure is not limited as in the sacrificial layer case. A two-degrees-of-freedom system is developed to study the effectiveness of the linear layer in reducing the damage. Several factors that affect the problem are discussed through a case study.