scholarly journals Acoustic Emission Generation at Fracture Point During Tensile Tests in the Thickness Direction of Particleboard : Effects of the Board's Internal Structure

10.5109/24427 ◽  
2001 ◽  
Vol 46 (1) ◽  
pp. 103-112
Author(s):  
Han Chien Lin ◽  
Mami Ishimoto ◽  
Yoshiyasu Fujimoto ◽  
Yasuhide Murase
Keyword(s):  
Acoustic Emission ◽  
Internal Structure ◽  
Tensile Tests ◽  
Thickness Direction

Investigation of the Staging of Damage Accumulation in Polymer Composite Materials during Bending and Tensile Tests

2021 ◽  
Vol 887 ◽  
pp. 116-122
Author(s):  
A.A. Bryansky ◽  
O.V. Bashkov ◽  
Daria P. Malysheva ◽  
Denis B. Solovev
Keyword(s):  
Acoustic Emission ◽  
Composite Materials ◽  
Polymer Composite ◽  
Loading Rate ◽  
Tensile Tests ◽  
Mechanical Tests ◽  
Rate Effect ◽  
Polymer Composite Materials ◽  
Static Tension ◽  
Point Bend

The paper presents the results of the study of registered acoustic emission (AE) parameters during static deformation and damaging of polymer composite materials (PCM). Mechanical tests were done by a static tension and a static three-point bend, accompanied by an acoustic emission method. The assessment of the loading rate effect on defects formation processes was done by additional static tension test at rate equal half of recommended by the standard and static three-point bend test at rate ten times lower than that calculated by the standard. Clustering by frequency components of the recorded AE signals with a self-organizing Kohonen map was performed. The characteristics of the types of PCM structure damage by the centroids of the obtained clusters are given. Based on the clusters accumulation during mechanical tests, the stages of damage formation for static tension and static three-point bend, the loading rate effect on the process of damage formation are described.

Проблемы локации источников акустической эмиссии

2021 ◽  
pp. 35-44
Author(s):  
Ю.Г. Матвиенко ◽  
И.Е. Васильев ◽  
Д.В. Чернов ◽  
В.И. Иванов ◽  
С.В. Елизаров
Keyword(s):  
Acoustic Emission ◽  
High Frequency ◽  
Tensile Tests ◽  
Threshold Method ◽  
Near Zone ◽  
Speed Dependence ◽  
Partial Energy ◽  
Base Size ◽  
Frequency Components ◽  
Amplitude Level

The accuracy of the location of acoustic emission (AE) sources in the concentrator zones (central holes 5 mm in diameter) located at a distance of 40 mm from the receiving transducers during tensile tests of steel, aluminum alloy and composite flat specimens with dimensions of 550x50x4 mm was evaluated. Calculated speed dependence of propagation of pulses on the level of their amplitude and the partial energy of the high-frequency components of the spectrum is studied. With the threshold method of signal registration, the error in the location of AE event sources arising in the near zone of the receiving transducers at a distance 𝛥L<0.1 m can significantly exceed 10% relative to the base size (B) of the location area, when B<0.5 m. Moreover, with a decrease in the distance 𝛥L<0.05 m, the level of possible error will increase, reaching 20-30% relative to the basic size of the antenna array, when recording pulses with an amplitude level um<60 dB and a fraction of the energy of high-frequency spectrum components not exceeding 10%.

Correlation among Microstructure, Texture, and Properties along the Thickness Direction in As-Hot-Rolled and As-Solution-Quenched Al7055 Thick Plates

2021 ◽  
Vol 1026 ◽  
pp. 65-73
Author(s):  
Kai Zhu ◽  
Hong Wei Yan
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
Tensile Tests ◽  
Rolled Plate ◽  
Uniaxial Tensile ◽  
Thickness Direction ◽  
Electron Backscattered Diffraction ◽  
Thick Plates ◽  
Aluminum Plates ◽  
Hot Rolled

Both microstructure inhomogeneity and mechanical property diversity along the thickness direction in rolled thick aluminum plates have been considered to have a remarkable impact on the performance and properties of the products made from the plates. In this study, scanning electron microscopy (SEM) and electron backscattered diffraction (EBSD) characterizations of microstructure and texture types along the thickness directions of Al7055 thick plate specimens prepared using two conditions, hot-rolling and solution-quenching, were performed. To examine the mechanical properties, uniaxial tensile tests were also carried out on specimens machined from both types of thick plates, using a layered strategy along the thickness direction. The results indicate that both the microstructure and mechanical properties are inhomogeneous under the two conditions. Furthermore, it is evident that there is a hereditary relationship between the mechanical properties of the two plates—areas with higher yield strength in the as-hot-rolled plate correspond to areas with the higher yield strength in the as-solution-quenched plate

scholarly journals Calibration Method for Monitoring Hygro-Mechanical Reactions of Pine and Oak Wood by Acoustic Emission Nondestructive Testing

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3775
Author(s):  
Chiara Bertolin ◽  
Lavinia de Ferri ◽  
Filippo Berto
Keyword(s):  
Acoustic Emission ◽  
Brittle Fracture ◽  
Digital Camera ◽  
Calibration Method ◽  
Tensile Tests ◽  
Damage Effect ◽  
Fracture Mechanisms ◽  
Dynamic Surface ◽  
Hardening Mechanism

The main issue of wood is its sensitivity to Relative Humidity (RH) variations, affecting its dimensional stability, and thus leading to crack formations and propagations. In situ structural health monitoring campaigns imply the use of portable noninvasive techniques such as acoustic emission, used for real-time detection of energy released when cracks form and grow. This paper proposes a calibration method, i.e., acoustic emission, as an early warning tool for estimating the length of new formed cracks. The predictability of ductile and brittle fracture mechanisms based on acoustic emission features was investigated, as well as climate-induced damage effect, leading to a strain-hardening mechanism. Tensile tests were performed on specimens submitted to a 50% RH variation and coated with chemicals to limit moisture penetration through the radial surfaces. Samples were monitored for acoustic emission using a digital camera to individuate calibration curves that correlated the total emitted energy with the crack propagation, specifically during brittle fracture mechanism, since equations provide the energy to create a new surface as the crack propagates. The dynamic surface energy value was also evaluated and used to define a Locus of Equilibrium of the energy surface rate for crack initiation and arrest, as well as to experimentally demonstrate the proven fluctuation concept.

scholarly journals Monitoring of reinforced concrete short ties with the acoustic emission technique

2019 ◽  
Vol 281 ◽  
pp. 04001
Author(s):  
Djillali Mezhoud ◽  
Jacqueline Saliba
Keyword(s):  
Acoustic Emission ◽  
Reinforced Concrete ◽  
Structural Integrity ◽  
Tensile Tests ◽  
Average Frequency ◽  
Rc Structures ◽  
Surrounding Matrix ◽  
High Adhesion ◽  
Damage Process ◽  
Different Characteristics

Cracking in Reinforced Concrete (RC) structures may impact their durability and their structural integrity. Cracking is mainly influenced by stress distribution along the interface between steel and concrete. Thus, quantitative evaluation of steel-concrete bond, which is responsible of transferring load from steel bar to the surrounding matrix, and its effect on fracture properties is of major important. An experimental investigation on RC ties is reported in this paper. Tensile tests have been conducted on cubic specimens with different high adhesion reinforcement diameters. Those tests have been monitored continuously using the Acoustic Emission (AE) technique for a better evaluation of the damage process. The results show a good correlation between the load and the AE activity. AE signals with different characteristics have been observed during the different fracture stages. Parameters such as duration and energy increased with the loading level and can be used as indicators to detect the macrocracking of concrete. A parametric analysis is performed between average frequency and RA value. Ib-value of AE hits has been also investigated and decreases to 0.12 prior to the first macro crack.

Application of signal processing to acoustic emission signals emitted by steel specimens during tensile tests

Ultrasonics ◽  
1982 ◽  
Vol 20 (1) ◽  
pp. 18-24 ◽  
Author(s):  
I. Lanchon-Magnin ◽  
P. Fleischmann ◽  
D. Rouby ◽  
R. Goutte
Keyword(s):  
Signal Processing ◽  
Acoustic Emission ◽  
Tensile Tests

Investigation of Oil Palm and Pineapple Fiber Reinforced Phenol Formaldehyde Composites by Acoustic Emission Technique

2003 ◽  
Vol 11 (1) ◽  
pp. 9-18 ◽  
Author(s):  
M. S. Sreekala ◽  
T. Czigány ◽  
G. Romhány ◽  
S. Thomas
Keyword(s):  
Acoustic Emission ◽  
Oil Palm ◽  
Fracture Behaviour ◽  
Phenol Formaldehyde ◽  
Composite Plates ◽  
Tensile Tests ◽  
Fiber Reinforced ◽  
Single Edge ◽  
Scanning Electron Microscopy Micrographs ◽  
Acoustic Emission Technique

The fracture mechanics response of oil palm and pineapple fiber reinforced phenol formaldehyde composites was investigated. The fracture behaviour was influenced by the fiber content, the length of the fibers and the condition of the fiber-matrix interface. Single edge notched tensile specimens were cut from composite plates and examined. The fracture toughness was determined from force-elongation curves. Tensile tests and acoustic emission investigations were carried out simultaneously. It was found out that the failure mode for untreated and treated materials was quite different. Scanning electron microscopy micrographs were taken from the fracture surfaces.

scholarly journals Damage evolution in wood – pattern recognition based on acoustic emission (AE) frequency spectra

Holzforschung ◽  
2015 ◽  
Vol 69 (3) ◽  
pp. 357-365 ◽  
Author(s):  
Franziska Baensch ◽  
Markus G.R. Sause ◽  
Andreas J. Brunner ◽  
Peter Niemz
Keyword(s):  
Pattern Recognition ◽  
Acoustic Emission ◽  
Cluster Formation ◽  
Low Frequency ◽  
Tensile Tests ◽  
Most Probable Number ◽  
Frequency Spectra ◽  
Probable Number ◽  
Ae Signal ◽  
Ae Signals

Abstract Tensile tests on miniature spruce specimens have been performed by means of acoustic emission (AE) analysis. Stress was applied perpendicular (radial direction) and parallel to the grain. Nine features were selected from the AE frequency spectra. The signals were classified by means of an unsupervised pattern recognition approach, and natural classes of AE signals were identified based on the selected features. The algorithm calculates the numerically best partition based on subset combinations of the features provided for the analysis and leads to the most significant partition including the respective feature combination and the most probable number of clusters. For both specimen types investigated, the pattern recognition technique indicates two AE signal clusters. Cluster A comprises AE signals with a relatively high share of low-frequency components, and the opposite is true for cluster B. It is hypothesized that the signature of rapid and slow crack growths might be the origin for this cluster formation.

Fatigue behavior and damage analysis by the acoustic emission technique of cross-ply laminates under tensile loading

2017 ◽  
Vol 13 (2) ◽  
pp. 150-164
Author(s):  
Imen Ben Ammar ◽  
Abderrahim El Mahi ◽  
Chafik Karra ◽  
Rachid El Guerjouma ◽  
Mohamed Haddar
Keyword(s):  
Acoustic Emission ◽  
Mechanical Behavior ◽  
Fatigue Behavior ◽  
Glass Fibers ◽  
Tensile Tests ◽  
Hybrid Fibers ◽  
Content Type ◽  
Laminated Materials ◽  
Ae Signals ◽  
Damage Investigation

Purpose The purpose of this paper is to study the mechanical behavior in fatigue tensile mode of different cross-ply laminates constituted of unidirectional carbon fibers, hybrid fibers and glass fibers in an epoxy matrix; and to identify and characterize the local damage in the laminated materials with the use of the acoustic emission (AE) technique. Design/methodology/approach The tests in the fatigue mode permitted the determination of the effect of the stacking sequences, thickness of 90° oriented layers and reinforcement types on the fatigue mechanical behavior of the laminated materials. The damage investigation in those materials is reached with the analysis of AE signals collected from fatigue tensile tests. Findings The results show the effects of reinforcement type, stacking sequences and thicknesses ratio of 90° and 0° layers on the mechanical behavior. A cluster analysis of AE data is achieved and the resulting clusters are correlated with the damage mechanism of specimens under loading tests. Originality/value The analysis of AE signals collected from tensile tests of the fatigue failure load allows the damage investigation in different types of cross-ply laminates which are differentiated by the reinforcement type, stacking sequences and thicknesses ratio of 90° and 0° layers.

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