Abstract
The information of applied external forces is very important and useful in the assessment of integrity of structures. An identification method of impact force is presented in this paper. First, the relation between force histories and strain responses is formulated based on the finite element method (FEM). By applying this formulation, an error vector that indicates the force location is defined with strain responses measured at multiple points in a structure. The inverse problem can be solved with the conventional least-square method, but in an actual system, the identified force history has a large oscillation because of the influence of measurement noise and FEM modeling error. To overcome this difficulty, second, the present paper proposes a reliable force identification method that imposes the penalty on the derivative of the force history. The present method has been applied to carbon fiber reinforced plastic (CFRP) laminated plates with a SMART Layer embedded lead zirconate titanate (PZT) piezoelectric sensors. The experimental results for two kinds of plates are reported in this paper. According to the results of force location and history identification, the validity of the present method is verified, and the influence of the modeling error involved in the finite element model is discussed.
