Characteristics of acoustic emission wave attenuation in short fibre reinforced plastics

Glass fiber-reinforced plastics (GFRP) is widely used in many industrial fields. When acoustic emission (AE) technology is applied for dynamic monitoring, the interfering signals often affect the damage evaluation results, which significantly influences industrial production safety. In this work, an effective intelligent recognition method for AE signals from the GFRP damage is proposed. Firstly, the wavelet packet analysis method is used to study the characteristic difference in frequency domain between the interfering and AE signals, which can be characterized by feature vector. Then, the model of back-propagation neural network (BPNN) is constructed. The number of nodes in the input layer is determined according to the feature vector, and the feature vectors from different types of signals are input into the BPNN for training. Finally, the wavelet packet feature vectors of the signals collected from the experiment are input into the trained BPNN for intelligent recognition. The accuracy rate of the proposed method reaches to 97.5%, which implies that the proposed method can be used for dynamic and accurate monitoring of GFRP structures.

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Study on Acoustic Emission Detection Technology of Fiber Reinforced Plastic Pressure Vessel

Volume 1: Codes and Standards ◽

10.1115/pvp2020-21088 ◽

2020 ◽

Author(s):

Daoxiang Wei ◽

Yuqing Yang ◽

Jun Si ◽

Xiang Wen

Keyword(s):

Acoustic Emission ◽

Pressure Vessel ◽

Pressure Vessels ◽

Fiber Reinforced ◽

Fiber Reinforced Plastic ◽

Glass Fiber Composites ◽

Reinforced Plastics ◽

Detection Technology ◽

Reinforced Plastic ◽

Emission Detection

Abstract Fiber reinforced plastics are used in pressure vessel manufacturing because of their high strength and corrosion resistance.Defects may occur in the manufacture and use of the pressure vessel. To ensure safe operation of the pressure vessel, it is necessary to conduct periodic safety assessment of the pressure vessel put into operation. It is difficult to evaluate the safety status of fiber-reinforced plastic pressure vessels by conventional nondestructive testing.Acoustic emission detection technology is a dynamic detection method, which has obvious advantages for the performance and fracture process of fiber reinforced plastic materials. ASME section V or ASTM section on acoustic emission detection of FRP pressure vessels, in which the localization of defects is mainly based on acoustic emission instruments. Due to the anisotropy of FRP material, the instrument can only give the area of the defect, and then use other non-destructive testing methods supplementary detection, so the author proposes a regional positioning method, which can locate defects more accurately. In this paper, acoustic emission detection method and lead breaking method were used to simulate the deficiency, and acoustic velocity attenuation and variation of fiber reinforced plastics were studied, and confirmative tests were carried out to obtain the positioning accuracy of the deficiency in different areas.In order to achieve the acoustic emission (AE) response behavior of stretching damage of glass fiber composites with fiber pre-broken and weak bonding, stretching tests and real-time AE monitoring of glass fiber composites were conducted.Experimental results showed that damage model such as matrix cracking and fiber fracture and bending could be occurred in the process of damage and failure. The composition and content of signal frequency of AE is also different because of difference of preset defect.

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Measurement of Acoustic Emission Wave Attenuation by Bones and Muscles

ASME 2007 Summer Bioengineering Conference ◽

10.1115/sbc2007-175825 ◽

2007 ◽

Author(s):

Benjamin Pruden ◽

Ozan Akkus

Keyword(s):

Acoustic Emission ◽

Wave Attenuation ◽

Physiological Activity ◽

Acoustic Emissions ◽

Biological Tissues ◽

The Body ◽

Frequency Range ◽

Mode Separation ◽

Viscous Losses

Stress fractures occur in bones of athletes and soldiers due to the accumulation of microcracks [1]. Detection of precursor acoustic emissions (i.e. ultrasonic stress waves) resulting from microcrack activity may help predict failure onset before continuous physiological activity results in full-blown fracture. An acoustic emission wave generated from a microcrack in bone will be diminished by dispersion, mode separation, reflection, and viscous losses induced by the biological tissues (skin, muscle, fat) between the source and the transducer. While others have recorded waves emanating from unknown loci in human knee in vivo using acoustic emission method [2], there is no means to appreciate how far these waves can travel in the body. Several studies have characterized the ultrasound attenuation in bone [3] and muscle analog homogenates [4] in the frequency range above 300 kHz. On the other hand, acoustic emissions are prominent in the range of 20 kHz to 300 kHz. The current study focused on identifying the attenuation of acoustic emission waves in bone and muscle tissues in a frequency range which is more relevant to acoustic emissions. This information is critical for predicting whether an emission of certain magnitude at the source can reach surface mounted sensors without being totally attenuated.

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Damage assessment of carbon fibre reinforced plastic using acoustic emission technique: experimental and numerical approach

Structural Health Monitoring ◽

10.1177/1475921720946438 ◽

2020 ◽

pp. 147592172094643

Author(s):

Claudia Barile ◽

Caterina Casavola ◽

Giovanni Pappalettera ◽

Vimalathithan Paramsamy Kannan

Keyword(s):

Finite Element ◽

Acoustic Emission ◽

Carbon Fibre ◽

Crack Length ◽

Research Work ◽

Numerical Approach ◽

Acoustic Energy ◽

Reinforced Plastics ◽

Reinforced Plastic ◽

Carbon Fibre Reinforced Plastic

In this research work, the acoustic emission results obtained from testing double cantilever beam specimens with carbon fibre reinforced plastic laminates are analysed. The acoustic emission descriptors such as amplitude, frequency centroid, counts, duration and risetime are clustered using k-means++ algorithm. An unconventional and innovative way of using the acoustic emission descriptors, after the clustering, is introduced. This method can favourably be used for relating the different damage progression modes in fibre reinforced plastics. Apart from this, the cumulative acoustic energy is used for predicting the crack length of the specimens. The predicted crack length is almost identical to the actual crack length opening recorded in each specimen. Finally, analytical and finite element models are used for validating the experimental results under the mode I delamination. The finite element studies are carried out using cohesive zone modelling in Comsol Multiphysics® platform.

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