Development of an Automated Impact Hammer for Modal Analysis of Structures

This report outlines the development and testing of a prototype compact automated impact hammer designed to be surface mounted on a structure to provide an impulse-based structural excitation source for vibration testing. The automated device was designed to be integrated with a distributed fibre optic sensing system which measures the in-plane dynamic strain of the structure at a spatially dense grid of sensing points. The hammer was tested on a composite plate with induced damage and the excitation and response data were used to generate complex curvature shapes for the plate. These data were in turn used with a structural health monitoring tool known as iSIDER that detects anomalies in complex operating curvature shapes to locate damage and other areas with structural stiffness variations. The impactor was shown to replicate the functionality of a modally tuned impact hammer that had been used previously. The analysed data correctly identified the impact damage location using a fully automated routine. APPROVED FOR PUBLIC RELEASE