Efficient implementation of Full Matrix Capture in real time ultrasonic damage imaging

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1 Efficient implementation of Full Matrix Capture in real time ultrasonic damage imaging Patrice Masson, Nicolas Quaegebeur, Pierre Claude Ostiguy GAUS, Mechanical Engineering Dept. Université de Sherbrooke Sherbrooke, QC, CANADA June 16, /21

Pierre Claude Ostiguy GAUS, Mechanical Engineering Dept.

2 Outline Context of Structural Health Monitoring (SHM) SHM and NDT at GAUS Motivation for the project Proposed imaging approach Application to SHM on a lap joint structure Bolted structure Riveted structure Application to NDT Conclusions and outlook 2/21

approach Application to SHM on a lap joint structure Bolted

3 Context of Structural Health Monitoring SHM using Guided Waves (GW) Guided wave propagation using piezoceramics (PZT) [Farrar] Application to impacts and delamination documented [Sohn,Su] Existing commercial solutions [Acellent, Metis Design] Compact or sparse array configurations 3/21

delamination documented [Sohn,Su] Existing commercial solutions [Acellent, Metis

4 SHM and NDT at GAUS PZT transducers design and configuration In plane arrays and laser micro machining Sparse and compact arrays design methodologies Advanced signal processing Time frequency and space wavenumber tools Sub band and broadband generation Guided waves propagation modeling Finite Element (FEM) and Spectral Element (SEM) Piezoceramic and damage interaction modeling Imaging algorithms Implementation of ToF approaches Dispersion based approaches (Excitelet) 4/21

broadband generation Guided waves propagation modeling Finite Element (FEM) and Spectral Element (SEM) Piezoceramic

5 SHM and NDT at GAUS 3 professors (P. Masson, A. Maslouhi and P. Micheau) 1 research assistant (N. Quaegebeur) 8 graduate students 5/21

6 Motivation for the project Investigated problem With classical imaging approaches, detection capabilities and accuracy of damage imaging decreases under multi modal or dispersive propagation. This work presents the validation of an imaging approach considering dispersion on a complex structure. Objectives Validate a new imaging approach for SHM. Demonstrate the interest of considering dispersion. Implement the approach on a more realistic structure, i.e. a lap joint. 6/21

This work presents the validation of an imaging approach considering dispersion on a complex structure.

7 Classical imaging approaches Reflection imaging Good localization (triangulation). Requires information on material properties (cg or cp). Does not require a dense array of transducers. Complexsignal processing implementation. Accuracy depends on transducer distribution. 7/21

8 Classical imaging approaches ToF approaches Localization of damages using Time of Flight (ToF). Compact or distributed arrays. Requires knowledge of group velocity (cg). Multimodal and dispersive propagation impair localization. 8/21

9 Proposed imaging approach Excitelet approach [Quaegebeur et al] Correlation of the measured signal with theoretical signal dispersed numerically. Considers multimodal and dispersive propagation. Requires knowledge of phase velocity (cp). 9/21

10 Proposed imaging approach 10/21

11 Preliminary validation Case study for notch monitoring Detection and localization of a simulated crack growth. 10 mm hole + notch from 2 mm to 10 mm. Compact PZT array of 7 elements (Ø 3 mm). Aluminum plate of 1.54 mm thickness. Experimental setup Linear compact micro machined array 11/21

12 Preliminary validation 12/21

13 Preliminary validation Case study for notch monitoring Able to detect crack as small as 2mm. Accurate localization of the crack. Able to monitor crack growth. 13/21

14 Application to SHM on a lap joint structure Experimental setup 14/21

15 Application to SHM on a lap joint structure Imaging over the whole structure for totally loosened bolt A 0 (top) and S 0 (middle) modes and combined (bottom). 15/21

16 Application to SHM on a lap joint structure Imaging with progressive loosening of the bolt A 0 (left) and S 0 (middle) modes and combined (right). 16/21

17 Application to SHM on a lap joint structure Fatigue crack monitoring of a riveted aerospace lap joint 17/21

18 Application to SHM on a lap joint structure Fatigue crack monitoring of a riveted aerospace lap joint Accurate detection. Accurate localization. Able to monitor crack growth of a realistic fatigue crack. 18/21

Accurate detection. Accurate localization.

19 Application to NDT Imaging with better resolution or fewer elements N=64 Omniscan MX N=64 N=32 N=16 Excitelet N=8 19/21

20 Conclusions and outlook Conclusions The Excitelet imaging approach can improve imaging localization, accuracy and robustness. Can be used on realistic aerospace structure. Fast implementation is possible (real time application). Requires the knowledge of material properties; but could be estimated in situ. Outlook Extension to composite and multilayered structures. 20/21

Fast implementation is possible (real time application).

21 Acknowledgements 21/21

Rock Bolt Condition Monitoring Using Ultrasonic Guided Waves

Rock Bolt Condition Monitoring Using Ultrasonic Guided Waves Bennie Buys Department of Mechanical and Aeronautical Engineering University of Pretoria Introduction Rock Bolts and their associated problems