Crushable Materials for Structural Blast Shields

An approximate analytical method is presented for evaluating the effects on structural response of blast shields composed of crushable materials. In the analysis it is assumed that the structure can be represented by a mass spring system with a constant restoring force and that the shield is composed of a rigid-locking material. The analysis gives the response of this idealized shield-structure model to initial peak triangular pulse loadings. The results show that shielding is ineffective unless the pulse duration is short with respect to a certain time characteristic of the shield. Shielding is most effective when the crushing strength is equal to the static strength of the protected structure and when the thickness is sufficiently great to preclude complete compaction of the shield.