Development of an Automated Impact Hammer for Modal Analysis of Structures.
Scientific Publication
- Report Number:
- DSTO-TN-1062
- Authors:
- Norman, P.E.; Jung, G.; Ratcliffe, C.; Crane, R.; Davis, C.
- Issue Date:
- 2012-02
- AR Number:
- AR-015-205
- Classification:
- Unclassified
- Report Type:
- Technical Note
- Division:
- Air Vehicles Division (AVD)
- Release Authority:
- Chief, Air Vehicles Division
- Task Sponsor:
- AVD
- Task Number:
- LRR 07/250
- File Number:
- 2011/1237193/1
- Pages:
- 26
- References:
- 3
- Terms:
- Vibration analysis; Impact; Bragg gratings; Structural health monitoring; Dynamic characteristics
- URI:
- http://hdl.handle.net/1947/10186
Abstract
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.
Executive Summary
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 response of the structure across a spatially dense grid of sensing points.; The work described in this report forms part of a contribution by DSTO to a re- search program on Structural Health Monitoring Through Environmental Excitation and Optical Fibre Sensors sponsored by the Office of Naval Research (ONR) under a Naval International Cooperative Opportunities in Science and Technology Program (NICOP). It is a collaborative research effort involving researchers from the US Naval Academy (USNA), Naval Surface Warfare Centre { Carderock Division (NSWCCD), the Australian Co-operative Research Centre for Advanced Composite Structures (CRCACS) and DSTO.; The ultimate goal of the three year research program is the demonstration and validation of a large area vibration-based structural health monitoring system on a large composite sub-structure using simulated environmental excitation and a network of surface-mounted fibre Bragg gratings for response measurement. This report documents an alternative excitation methodology which may be used as part of the structural health monitoring system in the absence of suitable environmental excitation.