An efficient approach for identifying impact force using embedded piezoelectric sensors

In this paper, an efficient technique is proposed for identifying the impact force acting on CFRP laminated plates. First, Chebyshev polynomial is employed to approximate the impact force history. The coefficients in Chebyshev polynomial are directly used as unknown parameters. The relation between these unknown parameters and the strain responses at the specified positions is formulated through the finite element method and the mode superposition method. By comparing the numerically estimated strains and the experimental ones, an optimization model is set up to solve this inverse problem by employing the quadratic programming method. By virtue of this technique, the solution of this inverse problem for identifying the impact force becomes very stable and accurate. Also, by comparing the traditional methods, which employ the values of impact force at the discrete time points in the time domain, the number of unknowns in this proposed method is reduced significantly, which leads to the shortening of identification time for the purpose of real-time identification. After obtaining the impact force history, the impact position is identified by comparing the numerical strains and experimental ones directly. The experimental system for identifying the impact force is set up. Two kinds of CFRP laminates are used to verify the present methodology. (c) 2006 Elsevier Ltd. All rights reserved.