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This research experimentally implements a new method to identify the location and magnitude of a single impulsive excitation to ceramic body armor, which is supported on a compliant torso. The method could easily be extended to other flexibly supported components that undergo rigid body dynamics. Impact loads are identified in two steps. First, the location of the impact force is determined from time domain acceleration responses by comparing them to an array of reference acceleration time histories. Then based on the estimated location, reference frequency response functions are used to reconstruct the input force in the frequency domain through a least squares inverse problem. Experimental results demonstrate the validity of this method at both low energy excitations, which are produced by a medium modally-tuned impact hammer, and at high energy excitations, which are produced by dropping rods with masses up to 0.6 kilograms from a height of 2 meters. The maximum error in the estimated location or magnitude for the low energy excitations on the 10 cm square ceramic body armor was 7.07 mm with an average error of 1.09 mm. In comparing the estimated force for the low energy excitations to the force recorded by the transducer in the modal impact hammer, the maximum error in the predicted force amplitude was 6.78 percent and the maximum error in the predicted impulse was 6.44 percent. For the high energy excitations, which produced accelerations at the measurement locations up to 50 times greater than that of the low energy excitations, the maximum error in the predicted location of the input force was 15 mm with an average error of 6.64 mm. There was no force transducer to capture the input force on the body armor from the rod, but from non-energy-dissipative projectile motion equations the validity of the solutions was confirmed by comparing the impulses.
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