A blast attenuator includes an enclosure defining a cavity; a core defining a plurality of interconnected pores, the core disposed in the cavity; and a shear thickening fluid disposed in the cavity, such that the shear thickening fills a portion of a pore volume of the core. A blast attenuation assembly includes a blast attenuator including a shear thickening fluid and a crushable element that omits a shear thickening fluid operably associated with the blast attenuator. A method includes the steps of providing a rigid core defining a plurality of interconnected pores and placing an enclosure about the core, the enclosure defining a filling port. The method further includes the steps of filling at least a portion of a pore volume of the core with a shear thickening fluid and closing the filling port to seal the enclosure and form a first blast attenuator.