Structural health monitoring technology for a full-scale aircraft structure under changing temperature

2014 ◽  
Vol 118 (1210) ◽  
pp. 1519-1537 ◽  
Author(s):  
D. Gao ◽  
Y. Wang ◽  
Z. Wu ◽  
G. Rahim
Keyword(s):  
Composite Structures ◽  
Lamb Waves ◽  
Orthogonal Experiment ◽  
Influence Factors ◽  
Full Scale ◽  
Analytical Prediction ◽  
Detection Capability ◽  
Operating Modes ◽  
Technology Applications ◽  
Different Temperatures

Abstract This paper presents optimal operating modes for the factors to maximise the detection capability of a given SHM technology in service environment. Firstly, an orthogonal experiment was performed to determine the importance ranking of the influence factors. Through the test, it is found that operating temperatures for SHM hardware and excitation frequencies for PZT actuator were the most critical factors. Then, numerical model of Lamb waves generated and received by PZT sensors were presented to predict the distribution of response signal amplitudes under changing temperature. Verification tests were carried out on a glass fibre reinforced composite plate at different temperatures. The comparison between the analytical prediction and test results was presented and temperature-dependent optimal frequencies for PZT actuators were obtained. Finally, SHM experiments of full-scale horizontal composite structures are presented. The detection capability of the SHM technology applications of aircrafts in real world is verified by the experimental results.

Full-scale tests on composite structures with low degree of shear connection

ce/papers ◽  
2017 ◽  
Vol 1 (5-6) ◽  
pp. 297-302
Author(s):  
Therese Sheehan ◽  
Xianghe Dai ◽  
Dennis Lam
Keyword(s):  
Composite Structures ◽  
Full Scale ◽  
Shear Connection ◽  
Low Degree ◽  
Full Scale Tests

The Preparation of Loaded Photocatalyst for Advanced Treatment of NH3-N in Coking Water

2013 ◽  
Vol 726-731 ◽  
pp. 2829-2832
Author(s):  
Yong Shu Tian ◽  
Run Xin Hou
Keyword(s):  
Photocatalytic Degradation ◽  
Orthogonal Experiment ◽  
Influence Factors ◽  
Advanced Treatment ◽  
Optimum Process ◽  
Process Conditions ◽  
Single Factor ◽  
Clay Brick ◽  
Degradation Rates ◽  
Single Factor Experiment

Photocatalyst of Fe-Sm-Yb modified TiO2 loaded on clay brick was prepared for degradation of NH3-N in coking water. The influence factors of NH3-N degradation rates were discussed by single factor experiment and orthogonal experiment. The optimum process conditions of photocatalytic degradation NH3-N in coking water were confirmed. The results show that NH3-N degradation rates 82.23% were highest in the conditions of pH 6.5, photocatalyst charge of 1.4 g, illumination for 6h, reaction at 55°C, calcination at 500°C.

The Effect of Ply Orientation and Damage Detection in Composite Stiffened Panel Using Lamb Waves

2019 ◽  
Vol 298 ◽  
pp. 161-166
Author(s):  
Ouadia Mouhat ◽  
Abdelmajid Bybi ◽  
Ahmed El Bouhmidi ◽  
Hasnae Boubel ◽  
Omaima Elmrabet ◽  
...  
Keyword(s):  
Acoustic Waves ◽  
Composite Structures ◽  
Laminate Composite ◽  
Lamb Waves ◽  
Stiffened Panel ◽  
Signal Acquisition ◽  
Frequency Increase ◽  
Stiffened Panels ◽  
Composite Stiffened Panel ◽  
Ply Orientation

The present work proposes a vibration study with different surface and layers orientations at 0°, 15°, 30°, 45°, 60°, 75° and 90°using the Abaqus finite element code, the frequencies Stratified laminate composite panels were studied and the comparison between damaged structures and perfect structures we used stiffened panels based on T-shaped reinforced fibers. Lamb waves (LW) were widely proposed for the long-range inspection of Structural Structural Health Monitoring (SHM) oriented composite structures, the obtained results show the angle effects on the natural frequency increase at a peak then decrease in the form of a sinusoidal half-curve and the numerical results found in this work can be compared to those of other authors in the same area of ​​research, A piezoelectric actuator is used to design acoustic waves and a sensor is used for signal acquisition.

scholarly journals Impact Localisation in Composite Plates of Different Stiffness Impactors under Simulated Environmental and Operational Conditions

Sensors ◽  
2019 ◽  
Vol 19 (17) ◽  
pp. 3659 ◽  
Author(s):  
Seno ◽  
Aliabadi
Keyword(s):  
Composite Structures ◽  
Lamb Waves ◽  
Real Life ◽  
Composite Plates ◽  
Information Criterion ◽  
Reference Database ◽  
Time Of Arrival ◽  
Operational Conditions ◽  
Contact Behaviour ◽  
Using Data

A parametric investigation of the effect of impactor stiffness as well as environmental and operational conditions on impact contact behaviour and the subsequently generated lamb waves in composite structures is presented. It is shown that differing impactor stiffness generates the most significant changes in contact area and lamb wave characteristics (waveform, frequency, and amplitude). A novel impact localisation method was developed based on the above observations that allows for variations due to differences in impactor stiffness based on modifications of the reference database method and the Akaike Information Criterion (AIC) time of arrival (ToA) picker. The proposed method was compared against a benchmark method based on artificial neural networks (ANNS) and the normalised smoothed envelope threshold (NSET) ToA extraction method. The results indicate that the proposed method had comparable accuracy to the benchmark method for hard impacts under various environmental and operational conditions when trained only using a single hard impact case. However, when tested with soft impacts, the benchmark method had very low accuracy, whilst the proposed method was able to maintain its accuracy at an acceptable level. Thus, the proposed method is capable of detecting the location of impacts of varying stiffness under various environmental and operational conditions using data from only a single impact case, which brings it closer to the application of data driven impact detection systems in real life structures.

Guided Lamb waves for identification of damage in composite structures: A review

2006 ◽  
Vol 295 (3-5) ◽  
pp. 753-780 ◽  
Author(s):  
Zhongqing Su ◽  
Lin Ye ◽  
Ye Lu
Keyword(s):  
Composite Structures ◽  
Lamb Waves
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