| Summary: | 碩士 === 國立屏東科技大學 === 機械工程系 === 88 === This work is mainly to make use of the force-predictive model, which is developed by Wu[4], extended to the cantilever beam for determining the amplitude, time history and location of the unknown impact force acting on the beam. The unknown impact force is assumed as the triangular force. The structural modal parameter, including natural frequencies, modal damping and mode shapes, can be obtained by theoretical or experimental modal analysis. The structural acceleration response due to the unknown impact force acting on a cantilever beam can be theoretically predicted or experimentally measured. The objective function can be defined as the sum of square errors between the predicted and measured response. The predicted response can then be expressed as functions of the amplitude, time history and location of the unknown impact force. The optimization problem can be formulated to solve for the amplitude and time history of the unknown impact force as well as the mode shape information associated with the location of the unknown impact force. In comparison to the structural mode shapes, the location of the impact force can so forth be known. This work verifies the feasibility and fitness of the force-predictive model developed by Wu[4] for the unknown impact force acting on the cantilever beam and demonstrates the force-predictive model applied to arbitrary structures. In the future, different sensors can be adopted in conjunction with the predictive model for force prediction problem.
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