13th International Conference on Fracture June 16–21, 2013, Beijing, China -8- from the AE measurements. 0 2 4 6 8 10 12 0,5 0,7 0,9 1,1 1,3 1,5 1,7 1,9 2,1 2,3 2,5 Crack position (cm) Displacement (mm) Visual crack position 50-60 dB 60-70 dB 70-80 dB 80-90 dB 90-105 dB Figure 6. AE-events location and visual crack position vs. displacement loading. In figure 6 is presented the crack front propagation curve obtained from the AE location process. The dynamic of the crack propagation is in good agreement with the results obtained with the image analysis. In addition, it was observed that the crack front appears to be associated with a Fracture Process Zone. Future works, based on AE waveform analysis using moment tensor components, will allow the crack classification and understand the mechanisms of this localized area. 4. Conclusion In this study, we observed that the AE technique is an efficient tool for characterizing the failure process in wood materials. First, the experiment showed that crack initiation and crack growth detected by the AE activities is in a good agreement with the image analysis results. A second point to observe is that progress in AE-energy, during the test, is very similar to changes in fracture energy calculated from the load-displacement curve. These results were obtained for the both approaches used in the analysis of acoustic data: global approach with considering AE-hit signals and localization approach by using AE-event signals. For future works, this experimental investigation shows that the use of the localization approach seems to be a very promising method to investigate the cracks mechanisms such as the process zone.
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