| Summary: | 碩士 === 國立屏東科技大學 === 機械工程系 === 87 === This work is to develop a force-predictive model for determining the amplitude, time history and location of the impact force acting on a simply-supported beam. The impact force is assumed as the triangular force that complies with the actual force. The structural modal parameter, including natural frequencies, modal damping and modal shapes, can be first obtained by theoretical approach or by experimental modal analysis. The structural acceleration response due to an impact force can then be measured and recorded. The predicted response can be formulated based on the modal domain analysis and can be expressed as functions of the amplitude, time history and location of the impact force. The sum of mean square errors between the predicted and measured response can then be defined as the objective function. An optimization problem is constructed and solved for the amplitude and time history of the impact force as well as the mode shape information associated with the location of the impact force. In comparison to the structural mode shape, the location of the impact force can so forth be determined. Finally, the PVDF sensor, an intelligent material, is successfully applied to the prediction of the impact force instead of the accelerometer. This work enhances the application of intelligent material structure systems (IMSS) to the force prediction problem. This work demonstrates the feasibility of the force-predictive model for the triangular force acting on the simply-supported beam and can be extended to other structures.
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