Sensor location optimization in experimental modal analysis of a composite fuselage panel

This paper concerns the various aspects of experimental investigations of the structural dynamics of a composite material fuselage panel. Tolerances in production process lead to some scatter in geometry and material parameters of nominally identical composite structures. Various measurement techniques and test setups applied for the same object lead to variable measurement data. Accurate characterisation of structural dynamic behaviour of an intact structure is of crucial importance for the Structural Health Monitoring. A large number of vibration based damage detection algorithms are available that can detect deviations in structural parameters. However, discriminating changes induced by real damage from changes determined by large variability in modal parameters of structures made of composite materials is a real challenge. This poses some threads to the reliability of damage detection algorithms. The effectiveness of any damage detection algorithm is limited by its sensitivity to structural changes, but false alarms may be caused by variability in test data. Industry operating in competitive market force a dramatic reduction of time for the test. This leads to reduction of the number of sensors. Demands posed by SHM reliability and industry needs are in contradiction. To find an optimal solution of this problem an intensive test campaign is carried out on an aircraft fuselage panel made of composite material. Several excitation and measurement techniques are hereto applied to the aim of studying the variability of test data and to identify best practices in dynamic testing on composite material. The goal is to get the high quality data with a reduced number of sensors.