scholarly journals Deformation and Failure Mechanism of Particulate Filled and Short Fiber Reinforced Thermoplastics: Detection and Analysis by Acoustic Emission Testing

Polymers ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3931
Author(s):  
Milán Ferdinánd ◽  
Róbert Várdai ◽  
János Móczó ◽  
Béla Pukánszky
Keyword(s):  
Acoustic Emission ◽  
Quantitative Estimation ◽  
Local Deformation ◽  
Poly Lactic Acid ◽  
Deformation And Failure ◽  
Polymer Systems ◽  
Emission Testing ◽  
Heterogeneous Polymer ◽  
Deformation Processes ◽  
Acoustic Emission Testing

Acoustic emission, the detection of signals during deformation, is a frequently used method for the study of local deformation processes occurring in heterogeneous polymer systems. Most of these processes result in the evolution of elastic waves which can be detected by appropriate sensors. The analysis of several parameters characterizing the waves offers valuable information about the possible deformation mechanism. The acoustic emission testing of composites may yield very different number of signals from a few hundred to more than 100,000. This latter was proved to be affected mainly by particle size, interfacial adhesion and composition, but other factors, such as matrix modulus and specimen size, also influence it. Local deformation processes are claimed to have a strong effect on macroscopic properties. Indeed, a close correlation was found between the initiation stress of the dominating particle related process derived from acoustic emission testing and the tensile strength in both polypropylene (PP) and poly(lactic acid) (PLA) composites. However, in polyamide (PA)-based heterogeneous polymer systems, deformations related to the matrix dominated composite properties. Besides forecasting failure, the method makes possible the determination of the inherent strength of lignocellulosic fibers being around 40 MPa as well as the quantitative estimation of adhesion strength for composites in which interactions are created by mechanisms other than secondary forces. The proposed approach based on acoustic emission testing proved that in PP/CaCO3 composites, the strength of adhesion can be increased by ten times from about 100 mJ/m2 to almost 1000 mJ/m2 in the presence of a functionalized polymer.

scholarly journals Acoustic Emission Testing and Ib-Value Analysis of Ultraviolet Light-Irradiated Fiber Composites

2021 ◽  
Vol 11 (14) ◽  
pp. 6550
Author(s):  
Doyun Jung ◽  
Wonjin Na
Keyword(s):  
Acoustic Emission ◽  
Irradiation Time ◽  
Tensile Load ◽  
Failure Behavior ◽  
Value Analysis ◽  
Emission Testing ◽  
Final Failure ◽  
Acoustic Emission Testing ◽  
Woven Glass Fiber ◽  
Ae Signals

The failure behavior of composites under ultraviolet (UV) irradiation was investigated by acoustic emission (AE) testing and Ib-value analysis. AE signals were acquired from woven glass fiber/epoxy specimens tested under tensile load. Cracks initiated earlier in UV-irradiated specimens, with a higher crack growth rate in comparison to the pristine specimen. In the UV-degraded specimen, a serrated fracture surface appeared due to surface hardening and damaged interfaces. All specimens displayed a linearly decreasing trend in Ib-values with an increasing irradiation time, reaching the same value at final failure even when the starting values were different.

Study of the Metal Crack Propagation by Acoustic Emission Testing

2011 ◽  
Vol 105-107 ◽  
pp. 2179-2182
Author(s):  
Wei Min Zhang ◽  
Shu Xuan Liu ◽  
Yong Qiu ◽  
Cheng Feng Chen
Keyword(s):  
Acoustic Emission ◽  
Crack Propagation ◽  
Acquisition System ◽  
Signal Acquisition ◽  
Sensor Signal ◽  
Acoustic Emission Sensor ◽  
Axial Tension ◽  
Emission Testing ◽  
Acoustic Emission Testing ◽  
Signal Operating

Crack propagation is the main reason which leads to the invalidity of the metal components. A set of detecting equipment based on the acoustic emission method was designed, and it was mainly composed of acoustic emission sensor, signal operating circuits and signal acquisition system. Specimens of 16MnR material were manufactured and the static axial tension test of them was carried on. Acoustic emission signals from the specimen were detected by acoustic emission equipment by using piezoelectric ceramic sensor. Signal datum were acquired and operated by the acquisition system, as well as the acquisition program written for it. The final results has demonstrated that acoustic emission equipment designed for the test performed well in acquiring the signals induced by the metal crack propagation.

Acoustic Emission Testing of Concrete Frame during Pseudo Dynamic Loading

2006 ◽  
Vol 13-14 ◽  
pp. 195-200
Author(s):  
Athanasios Anastasopoulus ◽  
S. Bousias ◽  
A. Tsimogiannis ◽  
T. Toutountzakis
Keyword(s):  
Acoustic Emission ◽  
Dynamic Testing ◽  
Frame Structure ◽  
Scale Model ◽  
Reinforced Concrete Frame ◽  
Energy Rate ◽  
Concrete Frame ◽  
Emission Testing ◽  
Real Size ◽  
Acoustic Emission Testing

Acoustic Emission (AE) monitoring was performed during Pseudo-Dynamic Testing of a torsionally unbalanced, two-storey, one-by-one bay reinforced concrete frame structure. The structure represented a 0.7-scale model of a real-size frame structure designed and detailed according to the standards prevailing in Greece in 60's, without engineered earthquake resistance. Real time monitoring of AE activity versus the complex applied load resulted in semi quantitative damage characterization as well as comparative evaluation of the damage evolution of the different size columns. Evolution of the AE energy rate per channel, as revealed from zonal location, and the energy rate of linearly located sources enabled the identification of damage areas and the forecast of crack locations before cracks were visible with naked eye. In addition to that, the results of post processing evaluation allowed for the verification of the witnessed damaged areas and formed the basis for quantitative assessment of damage criticality.

On the Reproducibility of Transducer Coupling for Acoustic Emission Testing

2006 ◽  
Vol 13-14 ◽  
pp. 117-124 ◽  
Author(s):  
James J. Hensman ◽  
C.V. Cristodaro ◽  
Gareth Pierce ◽  
Keith Worden
Keyword(s):  
Acoustic Emission ◽  
Test Results ◽  
Coupling Condition ◽  
Waveform Data ◽  
Three Point Bending ◽  
Emission Testing ◽  
Acoustic Emission Testing ◽  
Acoustic Emission Test ◽  
Point Bend ◽  
Ultrasonic Propagation

An acoustic emission test was simulated using a three point bend specimen and an artificial AE source. Waveform data was recorded as the sample was cyclically loaded in three point bending, and the cross correlation coefficient of the waveforms was used to measure the repeatability of the test. Results were twofold: the stress state of a specimen affects the ultrasonic propagation therein; and the coupling condition of a transducer may not remain constant during a test.

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