11. SUPPLEMENTARY NOTES

Äjgpicrvod tea gab&ß reisoßCj 13. ABSTRACT (Maximum 200 words) A method is introduced to identify an unknown impact on a composite plate. The identification includes the impact location and force time history. A distributed piezoelectric sensor array measures the plate response to the impact. An optimization technique solves the identification problem. The technique identifies the impact by comparing the calculated model response to the measured response. The identification method was implemented in the computer code IDIMPACT. To verify the identification system, many impacts were distributed on a 36-inch by 30-inch composite plate with a distributed surface-mounted piezoelectric sensors. The code proved to be a reliable and accurate identification system. The average error in the reported impact was.56 inch, and the average error in the energy of the forc