Abstract
Non-destructive damage detection and evaluation techniques have become an area of great interest. In the field of composites, where damage in the form of delamination can be present without being visually noticeable, damaged regions can present critical structural weaknesses. With advances in technology presenting Scanning Laser Doppler Vibrometry apparatus of higher accuracy and resolution than previously attainable, a high degree of analysis through differential calculus is attainable. Through the course of this paper, a new differential equation governing the detection of damaged regions is derived from the governing equation of motion of a gradient elastic flexural plate. The derived equation is applied to simulation data in clean format, and with the presence of synthetic noise, across both the first and second mode shapes of a narrow beam. For numerical calculus and data smoothing, the Savitzky-Golay differentiating filter is utilised. Finally, experimental data for the first mode frequency of a composite laminate beam is analysed and presented. The techniques derived are demonstrated to be capable of detecting and locating delamination damage without the requirement of either geometric or material properties and with no prior data as a comparison. The method is further found to be equally applicable across the first two resonant frequencies.
Original language | English |
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Pages | 772-779 |
Number of pages | 8 |
Publication status | Published - 1 Nov 2014 |
Event | 8th Australasian Congress on Applied Mechanics - Duration: 24 Nov 2014 → … |
Conference
Conference | 8th Australasian Congress on Applied Mechanics |
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Period | 24/11/14 → … |
Keywords
- Composites
- Delamination
- Governing differential equation
- Laser vibrometry
- Modal analysis
- Non-destructive testing
- Savitzky-golay filter