Real Time Identification for Natural Input Modal Testing

Natural input modal testing, or ambient vibration testing, or operational modal analysis, consists in extracting modal parameters of the structure excited by its natural operating loads using only its responses, contrary to classical modal analysis where the excitation is also known. In the space area, a classical approach but compatible with an interactive session was developed to reduce cost and development time of the structure by performing modal identification during its vibration qualification campaign. This method, called RTMVI (Real Time Modal Vibration Identification) and based on modal effective parameter concept can be adapted to natural input modal testing. This paper describes the method and its adaptations to this new context.