Impact identification of stiffened composite panels: I. System development

An investigation was conducted to develop a real-time identification technique for the prediction of the location and force history of low-velocity impacts on composite panels with beam stiffeners. The investigation included both analysis and experiments. Measurements from built-in piezoceramic sensors were used to reconstruct the force history using the smoother-filter algorithm. Impact location was determined by minimizing the difference between modeled response and actual response. Computer codes were developed for model construction (WFMODEL) and impact identification (WIDIMPACT). The model allowed for the variation of plate structural properties (density and stiffness) due to the presence of stiffeners. Results of extensive experiments verified the model, as coded in WFMODEL, for impacts both in the bay and on the stiffener. The identification technique, as implemented in the code WIDIMPACT, demonstrated real-time capability. Good agreement was found between predicted and actual force history and location, with success for different impact masses.