A constant scanning LDV technique for cylindrical structures: Simulation and measurement

The reliance of the aerospace industry on finite element models during the design of new products requires the best possible models for the prediction of the dynamic behaviour and so it is usually necessary to validate an original model using some additional reference data as the basis—usually data measured on a test structure. Finite element model updating can lead to the required accuracy, and while attempts are under way to minimise the required experimental testing involved in the process, measurements still are an integral part of the procedure. To improve the validation process, a major aim of current experimental research is to provide a more complete set of data from a single experiment in a shorter amount of time, so as to increase the overall efficiency of the updating routine. To this end, a new continuously scanning laser Doppler vibrometery measurement technique is presented for application to cylindrical structures. It allows the measurement of the dynamic behaviour of a cylindrical structure with a previously unachievable spatial resolution in a much shorter time than conventional measurement methods. The introduced method is evaluated through a detailed simulation in order to investigate its robustness and to ensure data quality, and the results from a proof-of-concept test rig are presented.