Input Force Identification in Time Domain Using Optimally Placed Accelerometers

Abstract

A technique in time domain is presented that aims at identifying dynamic loads acting on a structure from acceleration time response measured experimentally at finite number of locations on the structure. The structure essentially gets transformed into its own load transducer. The approach is based on the standard equilibrium equation in dynamics in time domain. For measurement of the acceleration response, there can be a large number of combinations of locations on the structure where the accelerometers can be mounted and the recovered loads may be quite sensitive to the locations selected for accelerometer placements. In fact, the precision with which the applied loads are estimated from measured acceleration response depends on the number of accelerometers utilized and their locations on the component. Implementation of a methodology to determine the optimum set of accelerometer locations, based on the sparse nature of the mass, damping and stiffness matrices, is presented to guide the selection of number and locations of accelerometers that will provide the most precise load estimates. A numerical validation that helps understand the main characteristics of the proposed approach is also presented. The numerical results reveal the effectiveness and utility of the proposed technique.