scholarly journals Damage Evolution and Fracture Events Sequence Analysis of Core-Shell Nanoparticle Modified Bone Cements by Acoustic Emission Technique

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 208
Author(s):  
O.F. Pacheco-Salazar ◽  
Shuichi Wakayama ◽  
L.A. Can-Herrera ◽  
M.A.A. Dzul-Cervantes ◽  
C.R. Ríos-Soberanis ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Bone Cement ◽  
Solid Phase ◽  
Bending Test ◽  
Fracture Mechanisms ◽  
Core Shell ◽  
Bone Cements ◽  
Four Point Bending ◽  
Ae Signals ◽  
Cement Formulation

In this research, damage in bone cements that were prepared with core-shell nanoparticles was monitored during four-point bending tests through an analysis of acoustic emission (AE) signals. The core-shell structure consisted of poly(butyl acrylate) (PBA) as rubbery core and methyl methacrylate/styrene copolymer (P(MMA-co-St)) as a glassy shell. Furthermore, different core-shell ratios 20/80, 30/70, 40/60, and 50/50 were prepared and incorporated into the solid phase of the bone cement formulation at 5, 10, and 15 wt %, respectively. The incorporation of a rubbery phase into the bone cement formulation decreased the bending strength and bending modulus. The AE technique revealed that the nanoparticles play an important role on the fracture mechanism of the bone cement, since a higher amount of AE signals (higher amplitude and energy) were obtained from bone cements that were prepared with the nanoparticles in comparison with those without nanoparticles (the reference bone cement). The SEM examination of the fracture surfaces revealed that all of the bone cement formulations exhibited stress whitening, which arises from the development of crazes before the crack propagation. Finally, the use of the AE technique and the fracture surface analysis by SEM enabled insight into the fracture mechanisms that are presented during four-point bending test of the bone cement containing nanoparticles.

RELATIONSHIP BETWEEN AE SIGNAL STRENGTH AND ABSOLUTE ENERGY IN DETERMINING DAMAGE CLASSIFICATION OF CONCRETE STRUCTURES

2016 ◽  
Vol 78 (5) ◽  
Author(s):  
Shahiron Shahidan ◽  
Siti Radziah Abdullah ◽  
Isham Ismail
Keyword(s):  
Acoustic Emission ◽  
Monitoring System ◽  
Concrete Structures ◽  
Signal Strength ◽  
Load Test ◽  
Bending Test ◽  
Damage Classification ◽  
Four Point Bending ◽  
Ae Signal ◽  
Absolute Energy

The most efficient tools in real monitoring system is acoustic emission (AE). This technique can be used to identify the damage classifications in RC structure. This research paper will mainly focus on the utilization of signal strength and Absolute energy (AE signal) in determining on the damage quantification for RC beam subjected to cyclic load test. The beam specimens size (150 X 250 X 1900) mm were prepared in the laboratory and tested with the four point bending test using cyclic loading together with acoustic emission monitoring system. The results showed that the analysis of AE data parameters is capable of determining the damage classification in concrete structures and the data corresponded to the visual observations during the increased loading cycle.

scholarly journals Application of New Techniques of Signal Processing for Detection of Wear Mechanisms in Turning of AISI 4340 Using Acoustic Emission

2021 ◽  
Author(s):  
Luis Henrique Andrade Maia ◽  
Alexandre Mendes Abrão ◽  
Wander Luiz Vasconcelos ◽  
Jánes Landre Júnior ◽  
Álisson Rocha Machado ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Wear Mechanisms ◽  
Tensile Tests ◽  
Machining Process ◽  
Fracture Mechanisms ◽  
Steel Turning ◽  
Short Time ◽  
Coated Carbide ◽  
Ae Signals ◽  
Aisi 4340

Abstract In this study, the short-time Fourier transform (STFT) technique was used to determine the wear mechanisms acting on uncoated and AlCrN-coated carbide tools and their variations during the machining process. To this end, tensile tests were performed on hardened AISI 4340 steel to characterize the acoustic emission (AE) signals and subsequently isolate the steel deformation and fracture mechanisms from the signs of tool wear during the steel turning. Machining tests were carried out using the following parameters: cutting speeds of 150, 200 and 250 m/min and feed rates of 0.10 and 0.20 mm/rev. The results demonstrate that AE signals in conjunction with STFT analysis can be used to identify abrasive wear, adhesive wear and other phenomena that occur during cutting.

scholarly journals A Crack Characterization Method for Reinforced Concrete Beams Using an Acoustic Emission Technique

2020 ◽  
Vol 10 (21) ◽  
pp. 7918 ◽  
Author(s):  
Md Arafat Habib ◽  
Cheol Hong Kim ◽  
Jong-Myon Kim
Keyword(s):  
Acoustic Emission ◽  
Reinforced Concrete ◽  
Crack Detection ◽  
Concrete Beams ◽  
Time History ◽  
Reinforced Concrete Beams ◽  
Bending Test ◽  
K Nearest Neighbor ◽  
Micro Cracks ◽  
Ae Signals

This study aims at characterizing crack types for reinforced concrete beams through the use of acoustic emission burst (AEB) features. The study includes developing a solid crack assessment indicator (CAI) accompanied by a crack detection method using the k-nearest neighbor (k-NN) algorithm that can successfully distinguish among the normal condition, micro-cracks, and macro-cracks (fractures) of concrete beam test specimens. Reinforced concrete (RC) beams undergo a three-point bending test, from which acoustic emission (AE) signals are recorded for further processing. From the recorded AE signals, crucial AEB features like the rise time, decay time, peak amplitude, AE energy, AE counts, etc. are extracted. The Boruta-Mahalanobis system (BMS) is utilized to fuse these features to provide us with a comprehensive and reliable CAI. The noise from the CAI is removed using the cumulative sum (CUMSUM) algorithm, and the final CAI plot is used to classify the three different conditions: normal, micro-cracks, and fractures using k-NN. The proposed method not only for the first time uses the entire time history to create a reliable CAI, but it can meticulously distinguish between micro-cracks and fractures, which previous works failed to deal with in a precise manner. Results obtained from the experiments display that the CAI built upon AEB features and BMS can detect cracks occurring in early stages, along with the gradually increasing damage in the beams. It also soundly outperforms the existing method by achieving an accuracy (classification) of 99.61%, which is 17.61% higher than the previously conducted research.

Damage accumulation studied by acoustic emission in bone cement prepared with core–shell nanoparticles under fatigue

2016 ◽  
Vol 51 (12) ◽  
pp. 5635-5645 ◽  
Author(s):  
O. F. Pacheco-Salazar ◽  
Shuichi Wakayama ◽  
Takenobu Sakai ◽  
C. R. Ríos-Soberanis ◽  
J. V. Cauich-Rodríguez ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Bone Cement ◽  
Damage Accumulation ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Core Shell Nanoparticles

NON-DESTRUCTIVE EVALUATION AND STRENGTH CHARACTERISTICS OF CFRP WITH HEAT DAMAGE

2006 ◽  
Vol 20 (25n27) ◽  
pp. 4285-4290 ◽  
Author(s):  
JIN WOOK KIM ◽  
YOUNG UN KIM ◽  
CHANG KWON MOON ◽  
SEOK HWAN AHN ◽  
KI WOO NAM
Keyword(s):  
Acoustic Emission ◽  
Structural Integrity ◽  
Matrix Cracking ◽  
Fracture Mechanisms ◽  
Heat Damage ◽  
Time Frequency ◽  
Reinforced Plastic ◽  
Damage Process ◽  
Distinct Frequency ◽  
Ae Signals

In this study, the heat-damage process of a carbon fiber reinforced plastic (CFRP) under monotonic tensile loading was characterized by acoustic emission. Additionally, epoxy specimens and prepreg specimens were used to determine the characteristics of acoustic emission (AE) signals of epoxy and fiber, respectively. The AE characteristics of CFRP showed three types of distinct frequency regions. Time-frequency analysis methods were employed for the analysis of fracture mechanisms in CFRP such as matrix cracking, debonding and fiber fracture. To evaluate the cumulative counts of AE signals, it seems that the results can be applied usefully to guarantee structural integrity and/or to the survey of destruction of the structure with heat-damage, that was made to the composite materials.

Wavelet Transform and Bispectrum Applied to Acoustic Emission Signals from Adherence Scratch-Tests on Corroded Galvanized Coatings

2006 ◽  
Vol 13-14 ◽  
pp. 83-88 ◽  
Author(s):  
Antolino Gallego ◽  
Jose F. Gil ◽  
J.M. Vico ◽  
Enrique Díaz Barriga-Castro ◽  
J.E. Ruzzante ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Acoustic Emission ◽  
Visual Inspection ◽  
Fracture Mechanisms ◽  
X Ray Diffraction ◽  
X Ray ◽  
Galvanized Coatings ◽  
Scratch Tests ◽  
Ae Signals ◽  
Scanning Electron

Wavelet analysis and bispectrum was applied to Acoustic Emission (AE) signals from scratch tests on corroded hot-dip galvanized samples in order to achieve the detection of corrosion products in pieces non reachable by visual inspection. AE signals were correlated with the fracture mechanisms occurring during scratch tests, while the contact force increased. Results were corroborated by Scanning Electron Microscopy (SEM), Energy Dispersive X-ray spectroscopy (EDX) and X-Ray Diffraction (XRD).

Investigation of the Stages of Damage Accumulation in Polymer Composite Materials

2019 ◽  
Vol 945 ◽  
pp. 515-521 ◽  
Author(s):  
O.V. Bashkov ◽  
A.A. Bryansky ◽  
I.V. Belova ◽  
Denis B. Solovev
Keyword(s):  
Acoustic Emission ◽  
Power Law ◽  
Experimental Studies ◽  
Amplitude Distribution ◽  
B Value ◽  
Bending Test ◽  
Emission Data ◽  
Three Point Bending ◽  
Destructive Processes ◽  
Ae Signals

This paper presents the results of the study of strength and fracture processes of FRP samples, obtained by vacuum and vacuum-autoclave molding methods. The experimental studies consisted of a three-point bending test with step loading, accompanied by an acoustic emission method. Based on the acoustic emission data recorded using the acoustic-emission software and hardware complex during the experiments, a method for estimating the accumulated damage using various techniques for analyzing acoustic emission parameters was tested. The results of methods for analyzing the power-law coefficient of accumulation of total AE, b-value and density distribution of amplitudes and median frequencies are considered. An estimate of the power-law coefficient of accumulation of the total AE made it possible to determine the bearing capacity of PCM samples. Using the techniques for analyzing the amplitude distribution of the AE signals and the distribution density of the amplitudes and median frequencies of the AE signals, destructive processes in the volume of samples were described and the stages of their damaging were revealed.

scholarly journals The Effect of TBB, as an Initiator, on the Biological Compatibility of PMMA/MMA Bone Cement

2020 ◽  
Vol 21 (11) ◽  
pp. 4016
Author(s):  
Kosuke Hamajima ◽  
Ryotaro Ozawa ◽  
Juri Saruta ◽  
Makiko Saita ◽  
Hiroaki Kitajima ◽  
...  
Keyword(s):  
Bone Cement ◽  
Solid Phase ◽  
Osteoblastic Differentiation ◽  
Bone Cements ◽  
Acrylic Bone Cement ◽  
Matrix Mineralization ◽  
Radical Production ◽  
Biological Compatibility ◽  
Spin Resonance ◽  
Cell Spread

Acrylic bone cement is widely used in orthopedic surgery for treating various conditions of the bone and joints. Bone cement consists of methyl methacrylate (MMA), polymethyl methacrylate (PMMA), and benzoyl peroxide (BPO), functioning as a liquid monomer, solid phase, and polymerization initiator, respectively. However, cell and tissue toxicity caused by bone cement has been a concern. This study aimed to determine the effect of tri-n-butyl borane (TBB) as an initiator on the biocompatibility of bone cement. Rat spine bone marrow-derived osteoblasts were cultured on two commercially available PMMA-BPO bone cements and a PMMA-TBB experimental material. After a 24-h incubation, more cells survived on PMMA-TBB than on PMMA-BPO. Cytomorphometry showed that the area of cell spread was greater on PMMA-TBB than on PMMA-BPO. Analysis of alkaline phosphatase activity, gene expression, and matrix mineralization showed that the osteoblastic differentiation was substantially advanced on the PMMA-TBB. Electron spin resonance (ESR) spectroscopy revealed that polymerization radical production within the PMMA-TBB was 1/15–1/20 of that within the PMMA-BPO. Thus, the use of TBB as an initiator, improved the biocompatibility and physicochemical properties of the PMMA-based material.

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