scholarly journals Health Monitoring of Aerospace Structures Utilizing Novel Health Indicators Extracted from Complex Strain and Acoustic Emission Data

Sensors ◽  
2021 ◽  
Vol 21 (17) ◽  
pp. 5701
Author(s):  
Georgios Galanopoulos ◽  
Dimitrios Milanoski ◽  
Agnes Broer ◽  
Dimitrios Zarouchas ◽  
Theodoros Loutas
Keyword(s):  
Acoustic Emission ◽  
Health Monitoring ◽  
Composite Structures ◽  
Phased Array ◽  
Essential Feature ◽  
Health Indicators ◽  
Sensor Data ◽  
Composite Panel ◽  
Emission Data ◽  
Variable Amplitude

The development of health indicators (HI) of diagnostic and prognostic potential from generally uninformative raw sensor data is both a challenge and an essential feature for data-driven diagnostics and prognostics of composite structures. In this study, new damage-sensitive features, developed from strains acquired with Fiber Bragg Grating (FBG) and acoustic emission (AE) data, were investigated for their suitability as HIs. Two original fatigue test campaigns (constant and variable amplitude) were conducted on single-stringer composite panels using appropriate sensors. After an initial damage introduction in the form of either impact damage or artificial disbond, the panels were subjected to constant and variable amplitude compression–compression fatigue tests. Strain sensing using FBGs and AE was employed to monitor the damage growth, which was further verified by phased array ultrasound. Several FBGs were incorporated in special SMARTapesTM, which were bonded along the stiffener’s feet to measure the strain field, whereas the AE sensors were strategically placed on the panels’ skin to record the acoustic emission activity. HIs were developed from FBG and AE raw data with promising behaviors for health monitoring of composite structures during service. A correlation with actual damage was attempted by leveraging the measurements from a phased array camera at several time instances throughout the experiments. The developed HIs displayed highly monotonic behaviors while damage accumulated on the composite panel, with moderate prognosability.

Automated Damage Detection in Composite Components Using Acoustic Emission

2013 ◽  
Vol 569-570 ◽  
pp. 80-87 ◽  
Author(s):  
Rhys Pullin ◽  
Matthew R. Pearson ◽  
Mark J. Eaton ◽  
Carol A. Featherston ◽  
Karen M. Holford ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Health Monitoring ◽  
Composite Structures ◽  
Impact Damage ◽  
Turbine Blades ◽  
Fatigue Loading ◽  
Potential Method ◽  
Base Line ◽  
Wind Turbine Blades ◽  
Ae Signals

The ability of a Structural Health Monitoring (SHM) system to automatically identify damage in a composite structure is a vital requirement demanded by end-users of such systems. This paper presents the demonstration of a potential method. A composite fatigue specimen was manufactured and initially tested at 1Hz for 1000 cycles. Acoustic emission (AE) signals were recorded for complete fatigue cycles periodically in order to establish a base-line associated with undamaged specimens. The specimen was then subjected to impact damage to create barely-visible impact damage (BVID) and subjected to further fatigue cycles with acoustic emission recorded until failure. The data was subsequently analysed using a range of techniques including basic RMS signal levels and frequency-based analysis. At various stages during the test, C-scanning was used to validate the results obtained. Results demonstrated that AE is capable of detecting BVID in composite materials under fatigue loading. The proposed method has wide applicability to composite structures which are subjected to cyclic loading, such as wind turbine blades.

scholarly journals Data Merging of AE Sensors with Different Frequency Resolution for the Detection and Identification of Damage in Oxide-Based Ceramic Matrix Composites

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4691
Author(s):  
Nicolas Guel ◽  
Zeina Hamam ◽  
Nathalie Godin ◽  
Pascal Reynaud ◽  
Olivier Caty ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Data Fusion ◽  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Sensor Data ◽  
Frequency Resolution ◽  
Matrix Composites ◽  
Emission Data ◽  
Damage Mechanisms ◽  
Detection And Identification

In this paper, acoustic emission data fusion based on multiple measurements is presented for damage detection and identification in oxide-based ceramic matrix composites. Multi-AE (acoustic emission) sensor fusion is considered with the aim of a better identification of damage mechanisms. In this context, tensile tests were conducted on ceramic matrix composites, fabricated with 3M™ Nextel™ 610 fibers and aluminosilicate matrix, with two kinds of AE sensors. Redundant and complementary sensor data were merged to enhance AE system capability and reliability. Data fusion led to consistent signal clustering with an unsupervised procedure. A correlation between these clusters and the damage mechanisms was established thanks to in situ observations. The complementarity of the information from both sensors greatly improves the characterization of sources for their classification. Moreover, this complementarity allows features to be perceived more precisely than using only the information from one kind of sensor.

scholarly journals Structural Health Monitoring for Advanced Composite Structures: A Review

2020 ◽  
Vol 4 (1) ◽  
pp. 13 ◽  
Author(s):  
Alfredo Güemes ◽  
Antonio Fernandez-Lopez ◽  
Angel Renato Pozo ◽  
Julián Sierra-Pérez
Keyword(s):  
Structural Health Monitoring ◽  
Fiber Optics ◽  
Health Monitoring ◽  
Composite Structures ◽  
Guided Waves ◽  
Probability Of Detection ◽  
Sensor Data ◽  
Structural Health ◽  
Early Fault Detection ◽  
Pod Analysis

Condition-based maintenance refers to the installation of permanent sensors on a structure/system. By means of early fault detection, severe damage can be avoided, allowing efficient timing of maintenance works and avoiding unnecessary inspections at the same time. These are the goals for structural health monitoring (SHM). The changes caused by incipient damage on raw data collected by sensors are quite small, and are usually contaminated by noise and varying environmental factors, so the algorithms used to extract information from sensor data need to focus on sensitive damage features. The developments of SHM techniques over the last 20 years have been more related to algorithm improvements than to sensor progress, which essentially have been maintained without major conceptual changes (with regards to accelerometers, piezoelectric wafers, and fiber optic sensors). The main different SHM systems (vibration methods, strain-based fiber optics methods, guided waves, acoustic emission, and nanoparticle-doped resins) are reviewed, and the main issues to be solved are identified. Reliability is the key question, and can only be demonstrated through a probability of detection (POD) analysis. Attention has only been paid to this issue over the last ten years, but now it is a growing trend. Simulation of the SHM system is needed in order to reduce the number of experiments.

Acoustic Emission and Ultrasound Phased Array Technique for Composite Material Evaluation

2013 ◽  
Author(s):  
Hossein Taheri ◽  
Fereidoon Delfanian ◽  
Jikai Du
Keyword(s):  
Acoustic Emission ◽  
Composite Materials ◽  
Composite Structures ◽  
Phased Array ◽  
Failure Modes ◽  
Acoustic Energy ◽  
Single Element ◽  
Signal Velocity ◽  
Acoustic Evaluation ◽  
Conventional Ultrasound

The successful application of various acoustic evaluation techniques to composite materials and structures depends on the understanding of the acoustic wave propagation mechanisms. However, due to the anisotropic nature of composite materials, where the acoustic signal velocity and attenuation depend on its traveling direction, the correlation of the different material failure modes to the recorded acoustic signals, such as during of an acoustic emission (AE) inspection, is difficult to be defined. This issue becomes even more challenging for ultrasound phased array technique, where unlike a conventional ultrasound single element transducer, an ultrasound phased array of sensors will generate and receive acoustic energy at various desired directions and locations. Such heightened flexibility and sensitivity is essential for the complex shape of modern composite structures. In this paper, the influence of fiber orientation on AE signal was first studied. AE parameters such as counts, duration, energy, rise time and amplitude for aluminum and composite plate were analyzed in MS-Excel and results were compared to AE software. Acoustic velocities along various fiber directions were also theoretically studied and experimentally measured. Then ultrasound phased array technique and related parameters such as ultrasound beam angle and focusing, frequency and material attenuation factors were quantitatively analyzed, and the optimization and limitation of ultrasound phased array inspection procedure were summarized.

scholarly journals Prediction of fiber breakage and matrix cracking in polymeric composites under low-cycle fatigue regimes by fuzzy and wavelet clustering of acoustic emission signals

2021 ◽  
Author(s):  
Sattar Mohammadi Esfarjani ◽  
Mohammad Azadi ◽  
Mohsen Alizadeh ◽  
Hassan Sayar
Keyword(s):  
Acoustic Emission ◽  
Composite Structures ◽  
Mechanical Test ◽  
Low Cycle Fatigue ◽  
Polymeric Composites ◽  
Matrix Cracking ◽  
Fiber Breakage ◽  
Cycle Fatigue ◽  
Emission Data ◽  
Pull Out

Abstract One of methods for detecting cracks and estimating their growth in materials such as composites is the acoustic emission technique. The detection of damages, cracks and their growth in industrial composite structures, under static and dynamic loads, has a significant importance, in order to prevent any damages and increase the reliability. Therefore, achieving required technical knowledge in this field, can be helpful in repairing and the maintenance of the part in industries. The prediction of the damage in polymeric composites under static loads has been already investigated by researchers; however, under cyclic loadings, researches about this behavior are still rare. In this study, by acoustic emission sensors and analyzing experimental data, the damage, including matrix cracking, the fiber breakage and other damages (debonding, fiber pull-out and delamination) during dynamic loading was investigated. At the first stage, standard specimens were made by the pure resin epoxy and the pure carbon fiber, subjected to monotonic tensile loading and then, the frequency of the failure was extracted. Then, composite specimens were loaded in the low-cycle fatigue regime. Mechanical test results and acoustic emission data were analyzed by fuzzy C-Means and wavelet transform methods and then compared to each other to find the percentage of failures in first, mid- and last cycles by the differentiation of failure types. Results clearly indicated that the acoustic emission approach is useful and an effective tool for identifying and detecting damages in polymeric composites.

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