Injury Potential of Shock Induced Compressive Waves on Human Bone

Recent military conflicts have provided evidence of significant lower extremity injury resulting from under-vehicle blasts. Improved vehicle design elements have decreased the frequency of hull breech into the occupant compartment, yet catastrophic injuries to the lower extremities continue to occur. In under-vehicle blast, the lower extremities, with intermediate to low acoustic impedance, are loaded by a high speed compression wave resulting from the blast load on the lower impedance vehicle armor. The dynamic stresses created in the tissues are significant and may exceed the dynamic strength of the bone. Numerical analysis of this steel plate/lower extremity interaction reveals the potential for the accumulation of stresses in the hard tissues, which has the potential to induce injuries separate from the more traditional inertia-based injuries. To investigate this potential injury mechanism, an experimental test was developed to apply high rate loading to a bone sample.