Calibration of Acoustic Emission Parameters in Relation to the Equilibrium Moisture Content Variations in a Pinus sylvestris Beam
Abstract
:1. Introduction
2. Materials and Methods
2.1. Experimental Setup
- Amplitude (A): is the peak in decibel during an acoustic emission event; it shows the disturbance level and the response of the sensor after power/energy loss. The set threshold value was 40 dB.
- Counts (C): it shows the number of times a signal exceeds a set threshold value. Real events have high counts.
- Energy (E): is the elastic energy released during an acoustic emission event, measured in arbitrary units (or energy units, e.u. = 10−14V2s). The AE energy can be determined using Equation (1), integrating the absolute or the squared values of the signal’s voltage curve over time [21]. Real events have high energy units.
2.2. Scots Pine Beam and Its Thermodinamic Equilibrium
2.2.1. Simil-CT Samplings of Scots Pine
2.2.2. Thermo-Dynamic Equilibrium of Moisture Content
2.3. Equilibrium Moisture Content Model and the Acoustic Emission Signals
3. Results and Discussions
3.1. Acoustic Emission Analysis
3.2. Gradient of the Equilibrium Moisture Content
3.3. Acoustic Emission vs. Equilibrium Moisture Content
4. Conclusions
- identify pre-existing macro or micro cracks in samples, which act as an open joint, reducing accumulated stress without emitting new acoustic emission events.
- point out damage caused by moisture variations, i.e., when the increasing ductility of the material generates no elastic energy.
Author Contributions
Funding
Acknowledgments
Conflicts of Interest
Appendix A
Equation | ESTD | |
---|---|---|
(A1) | 0.96 | 0.59 |
(A2) | 0.89 | 0.93 |
(A3) | 0.98 | 0.42 |
(A4) | 0.98 | 0.42 |
(A5) | 0.98 | 0.37 |
(A6) | 0.98 | 0.42 |
(A7) | 0.98 | 0.38 |
Equation | Coefficients (b) | |||||||
---|---|---|---|---|---|---|---|---|
Int. | x1 | x2 | x1∙x2 | x12 | x22 | x12 ∙x22 | ||
(A1) | 6.06 | 1.33 × 10−2 | −2.48 × 10−3 | 2.38 × 10−4 | ||||
(A2) | 1.19 | 1.27 × 10−1 | 1.06 × 10−2 | −3.65 × 10−4 | ||||
(A3) | 6.79 | −2.35 × 10−2 | −7.89 × 10−3 | 5.09 × 10−4 | −3.97 × 10−9 | |||
(A4) | 2.64 | 5.34 × 10−2 | 1.68 × 10−2 | 2.38 × 10−4 | −3.65 × 10−4 | −3.11 × 10−5 | ||
(A5) | 4.94 | −1.16 × 10−2 | 5.28 × 10−3 | 4.48 × 10−4 | −3.27 × 10−5 | −1.93 × 10−5 | −3.07 × 10−9 | |
(A6) | 6.79 | −2.35 × 10−2 | −7.89 × 10−3 | 5.09 × 10−4 | −3.97 × 10−9 | |||
(A7) | 3.15 | 9.41 × 10−2 | 1.98 × 10−1 | 1.14 × 10−4 | −4.60 × 10−5 | −1.61 × 10−5 | −1.88 × 10−1 |
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ID Number | Group | Directionality | Grain Angle | |
---|---|---|---|---|
50th percentile | 90th percentile | |||
S081, S091, S101, S111, S123, S142, S153, S173 | Group 1 | Parallel to grain | 4° | 9° |
S093, S122, S143, S152, S163, S172 | Group 2 | Not parallel to grain | 5° | 10° |
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Bartolucci, B.; Frasca, F.; Siani, A.M.; Bertolin, C. Calibration of Acoustic Emission Parameters in Relation to the Equilibrium Moisture Content Variations in a Pinus sylvestris Beam. Appl. Sci. 2021, 11, 5236. https://doi.org/10.3390/app11115236
Bartolucci B, Frasca F, Siani AM, Bertolin C. Calibration of Acoustic Emission Parameters in Relation to the Equilibrium Moisture Content Variations in a Pinus sylvestris Beam. Applied Sciences. 2021; 11(11):5236. https://doi.org/10.3390/app11115236
Chicago/Turabian StyleBartolucci, Beatrice, Francesca Frasca, Anna Maria Siani, and Chiara Bertolin. 2021. "Calibration of Acoustic Emission Parameters in Relation to the Equilibrium Moisture Content Variations in a Pinus sylvestris Beam" Applied Sciences 11, no. 11: 5236. https://doi.org/10.3390/app11115236