Time domain estimation of response and intensity in beams using wave decomposition and reconstruction

A method is described by which instantaneous values of the response, the internal forces and the intensity in beams can be estimated as functions of time. The individual components of intensity which propagate in each direction and the components due to shear and moment can also be estimated. The estimates are provided in real time by digitally filtering the outputs of an array of sensors. The digital filters are designed in the frequency domain using a wave decomposition approach and reconstructed in the time domain as FIR filters in this paper. The design and implementation process is described, numerical simulations of measurements in the farfield performed and an experimental implementation presented. The method is relatively insensitive to sensor miscalibration and measurement noise compared to other approaches, and yields instantaneous estimates as well as time averages. (C) 2000 Academic Press.