An energy dissipative element (24) protects hard disk drives (22, 72,
92) from shocks and vibrations. A closed elastic envelope (48) houses
a body of open cell foam (54), a volume of viscous liquid (56), and
a compressible gas (64). Under compression or expansion of the foam (54),
viscous liquid (56) flows through cell orifices and thereby dissipates energy
resulting from external force applied against the elastic wall (48). The
energy dissipative elements (24) are applied between a disk drive housing
(22) and an outer case (26) to create a ruggedized portable disk
drive module (20).