Reconstruction of turbine blade forces from response data

A procedure for estimation of the forcing functions on a turbine blade from response data is described. Solution of the inverse problem requires knowledge of the eigenproperties of the blade. The measured bending and torsional deflection data are transformed into modal responses. The modal responses are treated to be results of modal forces, which can be discretised in the time domain. A deconvolution procedure is developed to set up a matrix formulation to obtain the modal force description. Modal transformation is subsequently used to obtain the spatial distribution of forces. The procedure is illustrated for a typical turbine blade subjected to a set of chosen excitation forces distributed in the time and space domains. The computer simulated response of the blade due to these forces is treated as the `measured responseʹ and fed as input to the algorithm and the excitation forces are extracted.