Статті в журналах: "Defect size estimation"

1

Moskovchenko, Alexey, Michal Švantner, Vladimir Vavilov, and Arsenii Chulkov. "Characterizing Depth of Defects with Low Size/Depth Aspect Ratio and Low Thermal Reflection by Using Pulsed IR Thermography." Materials 14, no. 8 (April 10, 2021): 1886. http://dx.doi.org/10.3390/ma14081886.

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This study is focused on the quantitative estimation of defect depth by applying pulsed thermal nondestructive testing. The majority of known defect characterization techniques are based on 1D heat conduction solutions, thus being inappropriate for evaluating defects with low aspect ratios. A novel method for estimating defect depth is proposed by taking into account the phenomenon of 3D heat diffusion, finite lateral size of defects and the thermal reflection coefficient at the boundary between a host material and defects. The method is based on the combination of a known analytical model and a non-linear fitting (NLF) procedure. The algorithm was verified both numerically and experimentally on 3D-printed polylactic acid plastic samples. The accuracy of depth prediction using the proposed method was compared with the reference characterization technique based on thermographic signal reconstruction to demonstrate the efficiency of the proposed NLF method.

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2

Damaskinskaya, E. E., V. L. Hilarov, I. A. Panteleev, D. V. Korost, and K. A. Damaskinskii. "In-situ estimation of defect volume from parameters of acoustic emission signals." Journal of Physics: Conference Series 2103, no. 1 (November 1, 2021): 012066. http://dx.doi.org/10.1088/1742-6596/2103/1/012066.

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Abstract By using two methods of nondestructive testing, i.e., acoustic emission (AE) measurements and X-ray computed microtomography (CT), an experimental study of defect accumulation during a uniaxial compression of a natural heterogeneous material was carried out. A joint analysis of the AE and CT data revealed a correspondence between energy characteristics of the acoustic emission accompanying defect formation and volume of defects. It is shown that the dependence of the total energy of AE signals on the defect volume is linear, which is consistent with the phenomenological dependences for earthquake focuses obtained earlier. The linear dependence was used to estimate the average defect size. It is shown that, regardless of the assumed defect shape, its average linear size does not exceed 100 μm.

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3

Al-Ghamdi, A. M., P. Cole, R. Such, and D. Mba. "Estimation of bearing defect size with acoustic emission." Insight - Non-Destructive Testing and Condition Monitoring 46, no. 12 (December 1, 2004): 758–61. http://dx.doi.org/10.1784/insi.46.12.758.54491.

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4

Shim, Won Heum, Sejoong Rim, Sang Wook Lim, June Kwan, Jong Won Ha, Moon Hyoung Lee, Namsik Chung, Seung Yun Cho, and Sung Soon Kim. "Estimation of Size of Adult Atrial Septal Defect." Korean Circulation Journal 26, no. 3 (1996): 631. http://dx.doi.org/10.4070/kcj.1996.26.3.631.

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5

Wang, Hong'an, and Guoming Chen. "Defect size estimation method for magnetic flux leakage signals using convolutional neural networks." Insight - Non-Destructive Testing and Condition Monitoring 62, no. 2 (February 1, 2020): 86–90. http://dx.doi.org/10.1784/insi.2020.62.2.86.

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A method for defect size estimation of magnetic flux leakage (MFL) signals using convolutional neural networks (CNNs) is proposed to overcome the problem of quantitative identification of pipeline MFL testing. The model mainly includes two modules: defect classification and defect size regression. The former is used to realise data fusion, feature extraction and tasks of three components (axial, circumferential and radial) of the MFL defect signal. The defect size regression module includes seven CNNs, which realise the size estimation of different types of defect. The input is a different type of defect in the defect classification module and the output is the length, width and depth information of the defect. Finally, the training and prediction are conducted using a defect dataset. The results show that the proposed method can effectively identify the MFL defect size of the pipeline.

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6

Nabhan, Ahmed, and Ahmed Rashed. "Experimental and numerical investigation of defect-size estimation in taper roller bearing." Noise & Vibration Worldwide 49, no. 11 (September 26, 2018): 345–54. http://dx.doi.org/10.1177/0957456518801141.

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In this article, the estimation of different defect sizes present on the outer race of taper roller bearing confirms the effectiveness of the applied method for different vibration signals. Experiments and numerical model conducted for three primary conditions of bearing setting, which are positive, negative, and zero clearance. The outer race is installed in five different positions so that the defect located at 0°, 45°, 90°, 135°, and 180°. The output of the numerical model finds close correlation with the vibration signal pattern–obtained experiments. From the results, it is clear that defect-size estimation is more precise when the defect is introduced in the unloading area, and the contact time depends directly on the size of the defect, through which it is easy to calculate its value of the defect.

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7

Ciecieląg, Krzysztof, Krzysztof Kecik, and Kazimierz Zaleski. "Defects detection from time series of cutting force in composite milling process by recurrence analysis." Journal of Reinforced Plastics and Composites 39, no. 23-24 (June 20, 2020): 890–901. http://dx.doi.org/10.1177/0731684420935985.

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The article presents possibility of defects detection from milling time series using nonlinear methods: recurrence plots and recurrence quantifications. The defects are modeled as the holes with different diameters and depths. This allows estimation of the minimal size of defect possible to detect. Based on the conducted research, it has been shown that some of the recurrence indicators enable detection of defects. These recurrence indicators have been tested on the reals damage. Additionally, we show influence of the defect depth on the recurrence indicator values.

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8

Wermers, Jens, Benedikt Schliemann, Michael J. Raschke, Philipp A. Michel, Lukas F. Heilmann, Felix Dyrna, Julia Sußiek, Andre Frank, and J. Christoph Katthagen. "Glenoid concavity has a higher impact on shoulder stability than the size of a bony defect." Knee Surgery, Sports Traumatology, Arthroscopy 29, no. 8 (April 11, 2021): 2631–39. http://dx.doi.org/10.1007/s00167-021-06562-3.

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Abstract Purpose Surgical treatment of shoulder instability caused by anterior glenoid bone loss is based on a critical threshold of the defect size. Recent studies indicate that the glenoid concavity is essential for glenohumeral stability. However, biomechanical proof of this principle is lacking. The aim of this study was to evaluate whether glenoid concavity allows a more precise assessment of glenohumeral stability than the defect size alone. Methods The stability ratio (SR) is a biomechanical estimate of glenohumeral stability. It is defined as the maximum dislocating force the joint can resist related to a medial compression force. This ratio was determined for 17 human cadaveric glenoids in a robotic test setup depending on osteochondral concavity and anterior defect size. Bony defects were created gradually, and a 3D measuring arm was used for morphometric measurements. The influence of defect size and concavity on the SR was examined using linear models. In addition, the morphometrical-based bony shoulder stability ratio (BSSR) was evaluated to prove its suitability for estimation of glenohumeral stability independent of defect size. Results Glenoid concavity is a significant predictor for the SR, while the defect size provides minor informative value. The linear model featured a high goodness of fit with a determination coefficient of R2 = 0.98, indicating that 98% of the SR is predictable by concavity and defect size. The low mean squared error (MSE) of 4.2% proved a precise estimation of the SR. Defect size as an exclusive predictor in the linear model reduced R2 to 0.9 and increased the MSE to 25.7%. Furthermore, the loss of SR with increasing defect size was shown to be significantly dependent on the initial concavity. The BSSR as a single predictor for glenohumeral stability led to highest precision with MSE = 3.4%. Conclusion Glenoid concavity is a crucial factor for the SR. Independent of the defect size, the computable BSSR is a precise biomechanical estimate of the measured SR. The inclusion of glenoid concavity has the potential to influence clinical decision-making for an improved and personalised treatment of glenohumeral instability with anterior glenoid bone loss.

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9

Chen, Aoyu, and Thomas R. Kurfess. "A new model for rolling element bearing defect size estimation." Measurement 114 (January 2018): 144–49. http://dx.doi.org/10.1016/j.measurement.2017.09.018.

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10

Vasseur, Julien, Dmytro Vasiukov, Salim Chaki, Isabel Huther, Michel Marzin, Fabien Lefebvre, Benoît Dupont, and Nicolas Leymarie. "Fracture and determination of a lifetime of in-service mechanical components with porosity cluster in an aluminium alloy." MATEC Web of Conferences 300 (2019): 04001. http://dx.doi.org/10.1051/matecconf/201930004001.

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This paper focuses on the fatigue lifetime estimation of metallic components containing group of porosities as manufacturing defects. In order to represent these defects, six test specimens with different Side Drilled Holes (SDH) clusters, have been made of 7075-T6 aluminium alloy. Main characteristics of such defect (elementary size of porosities, spatial density or gradient of elementary sizes) have been studied by taking it into account in a FEM modelling in fatigue to determine their influence on the lifetime. Experimental tensile fatigue tests have been performed on all SDH samples with load ratio R=0.1. Semi-elliptical surfaces with a size of a typical Mg2Si particle of the studied alloy have been chosen as initial cracks for multiple crack propagation. Indeed, such a particle is often responsible for the initiation of a crack in this type of material. For crack growth, Paris’ type propagation law has been used. Local stress redistribution due to presence of the SDH implies mix-mode behaviour which has been considered by using G-theta method. Simulations results allowed realistic lifetime estimation according to the experimental ones. Moreover, a strong dependency of the crack paths and fatigue lifetime on the defect characteristics has been proved and quantified.

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11

Hou, Guang-Quan, and Chang-Myung Lee. "Estimation of the Defect Width on the Outer Race of a Rolling Element Bearing under Time-Varying Speed Conditions." Shock and Vibration 2019 (January 3, 2019): 1–11. http://dx.doi.org/10.1155/2019/8479395.

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Fault diagnosis and failure prognostics for rolling element bearing are helpful for preventing equipment failure and predicting the remaining useful life (RUL) to avoid catastrophic failure. Spall size is an important fault feature for RUL prediction, and most research work has focused on estimating the fault size under constant speed conditions. However, estimation of the defect width under time-varying speed conditions is still a challenge. In this paper, a method is proposed to solve this problem. To enhance the entry and exit events, the edited cepstrum is used to remove the determined components. The preprocessed signal is resampled from the time domain to the angular domain to eliminate the effect of speed variation and measure the defect size of a rolling element bearing on outer race. Next, the transient impulse components are extracted by local mean decomposition. The entry and exit points when the roller passes over the defect width on the outer race were identified by further processing the extracted signal with time-frequency analysis based on the continuous wavelet transform. The defect size can be calculated with the angle duration, which is measured from the identified entry and exit points. The proposed method was validated experimentally.

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12

Sharath, D., M. Menaka, and B. Venkatraman. "Defect Depth Quantification Using Pulsed Thermography." Advanced Materials Research 585 (November 2012): 72–76. http://dx.doi.org/10.4028/www.scientific.net/amr.585.72.

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Pulsed Thermography is an advanced NDE technique which is becoming popular due to fast inspection rate, non contact nature and it gives full field image. Pulsed Thermography is successfully applied for defect detection, defect depth estimation, coating thickness evaluation and delamination detection in coatings but it is limited for evaluation of subsurface defects (of the order of few mm). In this paper we discuss the application of Pulsed Thermography for defect quantification and effect of defect size on it in AISI 316 grade SS which are important structural materials used in nuclear and other industries. Log First Derivative method is considered for defect depth quantification and the results are compared with Finite Difference Modeling carried out using ThermoCalc 6L software.

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13

Shang, H. M., M. Lwin, and T. E. Tay. "Holographic Inspection of Plates Containing Areas of Localized Thickness Variation." Journal of Engineering Materials and Technology 116, no. 2 (April 1, 1994): 162–67. http://dx.doi.org/10.1115/1.2904267.

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Circular plates, under unknown clamping conditions and containing simulated defects in the form of circular localized thinning or thickening, are inspected by double-exposure holography. With an incremental uniform pressure applied between exposures, eccentric defects are readily revealed from the distinct irregular fringe patterns. In the case of central circular defects, however, the absence of distinct irregular fringe patterns does not enable easy visual detection of the defects. The simple method of analysis described in this paper, based on the fact that the displacement in a defective plate differs from that in a defect-free plate, allows easy deduction of central and eccentric defects from the fringe patterns. Furthermore, this method enables identification of the type of defect (localized thinning or thickening), the extent of thickness variation, as well as an accurate estimation of the location and size of the defect.

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14

Behzad, M., A. AlandiHallaj, A. Rohani Bastami, D. Mba, B. Eftekharnejad, and B. Charnley. "Defect size estimation in rolling element bearings using vibration time waveform." Insight - Non-Destructive Testing and Condition Monitoring 51, no. 8 (August 2009): 426–30. http://dx.doi.org/10.1784/insi.2009.51.8.426.

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15

Mba, D. "The Use of Acoustic Emission for Estimation of Bearing Defect Size." Journal of Failure Analysis and Prevention 8, no. 2 (March 5, 2008): 188–92. http://dx.doi.org/10.1007/s11668-008-9119-8.

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16

Obeidat, Omar, Qiuye Yu, Lawrence Favro, and Xiaoyan Han. "The effect of defect size on the quantitative estimation of defect depth using sonic infrared imaging." Review of Scientific Instruments 90, no. 5 (May 2019): 054902. http://dx.doi.org/10.1063/1.5078380.

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17

Patel, Priyank, and V. N. Patel. "Experimental study on enhancement of defect detection and defect size estimation in deep groove ball bearing." IOP Conference Series: Materials Science and Engineering 810 (May 5, 2020): 012039. http://dx.doi.org/10.1088/1757-899x/810/1/012039.

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18

Urnev, A. S., A. S. Chernyatin, Yu G. Matvienko, and I. A. Razumovskii. "Experimental and numerical sizing of a delamination defect in layered composite materials." Industrial laboratory. Diagnostics of materials 84, no. 10 (October 26, 2018): 59–66. http://dx.doi.org/10.26896/1028-6861-2018-84-10-59-66.

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A methodical approach to the estimation of the localization zone and geometric parameters of a delamination defect in layered composite materials is presented on the basis of mathematical processing of the experimental results of deformation measurements obtained with a grid of fiber-optic sensors. The results of methodological developments related to the determination of the optimal topology of the grid of sensors to ensure the detection of defects of a given size with the necessary accuracy and determination of their parameters are presented. We present methods for computational analysis and simulation of the strain-stress state in the defect zone, based on the algorithm used for modeling the problems of strain-stress analysis in the defect zone using 2D finite elements, instead of 3D ones, thus allowing the use a model of lower dimensionality and retain all the features of the stress-strain state. The results of methodological developments related to the determination of the defect parameters from the results of strain measurements using the methodology of solving the inverse problem, based on solving the problem of minimizing the discrepancy between the vector of deformation response and the vector of initial parameters are presented. The technique is implemented as a software consisting of a series of macros for ANSYS and programs for MATLAB. The results of cyclic testing of a sample from a multilayer CM with a delamination type of defect are presented. Estimation of the increment in the defect size upon loading is performed by mathematical processing of data recorded by fiber-optic strain sensors glued on one of the sample surfaces, based on the solution of the inverse problem. Comparison of the results of calculations of geometric parameters of the defects with the measurement data obtained by the method of ultrasonic flaw detection showed good agreement between them.

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19

SHIRAISHI, Yoichi. "An Appearance Inspection with Defect Size Estimation based on Deep Learning Algorithm." Journal of The Surface Finishing Society of Japan 71, no. 7 (July 1, 2020): 442–47. http://dx.doi.org/10.4139/sfj.71.442.

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20

Moroder, Philipp, Philipp Damm, Guido Wierer, Elisabeth Böhm, Marvin Minkus, Fabian Plachel, Sven Märdian, Markus Scheibel, and Mohammad Khatamirad. "Challenging the Current Concept of Critical Glenoid Bone Loss in Shoulder Instability: Does the Size Measurement Really Tell It All?" American Journal of Sports Medicine 47, no. 3 (January 14, 2019): 688–94. http://dx.doi.org/10.1177/0363546518819102.

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Background: Bone loss at the anterior glenoid rim is a main reason for failure of soft-tissue based surgical stabilization procedures in patients with anterior shoulder instability. Purpose: To evaluate the capability of conventional glenoid bone loss measurement techniques to provide an adequate estimation of the actual biomechanical effect of glenoid defects. Study Design: Descriptive laboratory study. Methods: Thirty consecutive patients with unilateral anterior shoulder instability and varying degrees of glenoid defect were included. Patient-specific computer tomography–based 3-dimensional shoulder models of the affected and unaffected sides were created. The bony shoulder stability ratio (SR) was determined in various potential dislocation directions with finite element analysis. Values obtained from conventional glenoid defect size measurement techniques (Pico and Sugaya) were correlated with the finite element analysis results. Additionally, a mathematical model was developed to theoretically analyze the correlation between glenoid defect size measurements and the SR. Results: The authors found substantial interindividual differences of the SR of the unaffected shoulders in all directions of measurement. Bone loss at the anterior glenoid rim significantly reduced the SR in the 2-o’clock ( P = .011), 3-o’clock ( P < .001), and 4-o’clock ( P < .001) directions referring to a right shoulder. The correlation between the defect size measurements and the SR for the 2-o’clock (rho = −0.522 and −0.580), 3-o’clock (rho = −0.597 and −0.580), and 4-o’clock (rho = −0.527 and −0.522) directions was statistically significant. However, it showed only moderate strength and was nonlinear as well as dependent on the inherent shape of the concavity. As shown by the mathematical model, bone loss has the most considerable effect at the edge of the glenoid rim, and an increasingly concave-shaped glenoid leads to an increase in loss of SR provoked by the same extent of bone loss. Conclusion: Current glenoid bone loss measurements are unable to provide an adequate estimation on the actual biomechanical effect of glenoid defects because (1) the relation between the glenoid defect size and its biomechanical effect is nonlinear and (2) patients with shoulder instability have constitutional biomechanically relevant glenoid concavity shape differences. Clinical Relevance: These findings challenge the current concept of setting a general threshold for critical glenoid bone loss, which requires bony reconstruction surgery.

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21

Murthy, Aravind N., Karl A. Flechsig, Wes Hillman, Keith Conard, and Remmelt Pit. "Thermal fly-height controlled glide for disk defect detection and defect size estimation for hard disk drives." Microsystem Technologies 20, no. 8-9 (April 24, 2014): 1523–27. http://dx.doi.org/10.1007/s00542-014-2160-5.

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22

Jun, Hyun Kyu, and Won Hee You. "Estimation of Crack Growth Life in Rail with a Squat Defect." Key Engineering Materials 417-418 (October 2009): 313–16. http://dx.doi.org/10.4028/www.scientific.net/kem.417-418.313.

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Rolling contact fatigue initiated defects such as surface corrugation, head check, squat, are one of growing problems in high speed railway line. A squat is generally developed below the rail surface and grows parallel to surface until it turns down into rail. Estimation of critical crack size and crack growth rate is an essential to prevent rail from failure and develop cost effective railway maintenance strategy. In this study, we predict crack growth rate of a rail with a squat defect. For this purpose, a rail model with a squat defect is developed. Timoshenko’s beam theory is applied to calculate the global bending stress at the crack tip and Hertzian contact model is applied to calculate the local contact stresses at the surface of rail by simulating rolling over a railway wheel on a rail. Stress intensity factors are calculated from the total stress at the crack tip. Fatigue crack growth curve of 60kg rail steel is applied to calculated crack growth rate. Software to predict crack growth life through whole life cycle is developed. We expect that we can make a more cost effective rail maintenance strategy by considering the crack growth analysis for a defective rail.

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23

Han, Dae-Hyun, and Lae-Hyong Kang. "GUI Development for Automatic Defect Visualization and Size Estimation Using Image Analysis Processing." Transactions of the Korean Society of Mechanical Engineers - A 42, no. 10 (October 31, 2018): 931–38. http://dx.doi.org/10.3795/ksme-a.2018.42.10.931.

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24

Allevi, Gloria, Giuseppe Pandarese, and Gian Marco Revel. "Improvement of defect size and morphological estimation in shearography inspection by wavelet transform." Review of Scientific Instruments 90, no. 10 (October 1, 2019): 105111. http://dx.doi.org/10.1063/1.5093146.

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25

Raišutis, Renaldas, Kumar Anubhav Tiwari, Egidijus Žukauskas, Olgirdas Tumšys, and Lina Draudvilienė. "A Novel Defect Estimation Approach in Wind Turbine Blades Based on Phase Velocity Variation of Ultrasonic Guided Waves." Sensors 21, no. 14 (July 17, 2021): 4879. http://dx.doi.org/10.3390/s21144879.

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The reliability of the wind turbine blade (WTB) evaluation using a new criterion is presented in the work. Variation of the ultrasonic guided waves (UGW) phase velocity is proposed to be used as a new criterion for defect detection. Based on an intermediate value between the maximum and minimum values, the calculation of the phase velocity threshold is used for defect detection, location and sizing. The operation of the proposed technique is verified using simulation and experimental studies. The artificially milled defect having a diameter of 81 mm on the segment of WTB is used for verification of the proposed technique. After the application of the proposed evaluation technique for analysis of the simulated B-scan image, the coordinates of defect edges have been estimated with relative errors of 3.7% and 3%, respectively. The size of the defect was estimated with a relative error of 2.7%. In the case of an experimentally measured B-scan image, the coordinates of defect edges have been estimated with relative errors of 12.5% and 3.9%, respectively. The size of the defect was estimated with a relative error of 10%. The comparative results obtained by modelling and experiment show the suitability of the proposed new criterion to be used for the defect detection tasks solving.

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26

Kumar, Anil, and Rajesh Kumar. "Enhancing Weak Defect Features Using Undecimated and Adaptive Wavelet Transform for Estimation of Roller Defect Size in a Bearing." Tribology Transactions 60, no. 5 (October 8, 2016): 794–806. http://dx.doi.org/10.1080/10402004.2016.1213343.

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Périgo, E. A., E. P. Gilbert, and A. Michels. "Magnetic SANS study of a sintered Nd–Fe–B magnet: Estimation of defect size." Acta Materialia 87 (April 2015): 142–49. http://dx.doi.org/10.1016/j.actamat.2014.12.051.

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Cui, Ai Qiang, Shao Ping Zhou, Wen Chao Lv, and Chang Li Liu. "Simulation Research on Defects Detection in Straight Pipes Using Guided Waves." Applied Mechanics and Materials 226-228 (November 2012): 526–30. http://dx.doi.org/10.4028/www.scientific.net/amm.226-228.526.

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Ultrasonic guided wave provides a suitable fast screening technique that enables the localization of the defects and offers a rough estimation of the defect size in pipes. Using the ANSYS, the entity model of a pipe with defects such as cracks and holes was established in this paper. Then the L(0,2) mode guided wave was excited by exerting symmetric displacement loads on an end of the pipe model. By analyzing the incident wave and the reflected wave of defects, the axial location and circumferential location of the defects can be reached. Besides, by fitting the data with some certain formulas, the relationships between reflection coefficient and the defects extent can be acquired. This new technique is of great significance in nondestructive detection.

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Ben Ahmed, Amal, Ahmad Bahloul, Mohamed Iben Houria, Anouar Nasr, and Raouf Fathallah. "Multiaxial fatigue life estimation of defective aluminum alloy considering the microstructural heterogeneities effect." Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications 233, no. 9 (August 16, 2018): 1830–42. http://dx.doi.org/10.1177/1464420718792024.

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The Al–Si–Mg high-cycle fatigue behavior is mainly affected by the microstructural heterogeneities and the presence of casting defects. This attempt aims to develop an analytical approach based on the evaluation of the highly stressed volume caused by local porosities and defined as the affected area methodology. The proposed approach is able to predict the aluminum alloy fatigue response by considering the effect of microstructure described by the secondary dendrite arm spacing and its correlation with the defect size effect. A representative elementary volume model is implemented to evaluate the stress distribution in the vicinity of the defect and to determine its impact on the high-cycle fatigue resistance. Work hardening due to cyclic loading is considered by applying the Lemaitre–Chaboche model. The Kitagawa–Takahashi diagrams corresponding to different microstructures and for two loading ratios: R σ = 0 and R σ = −1 were simulated based on the AA method. Simulations were compared to the experimental results carried out on cast aluminium alloy A356 with T6 post heat-treatment. The results show clearly that the proposed approach provides a good estimation of the A356-T6 fatigue limit and exhibits good ability in simulating the Kitagawa–Takahashi diagrams for fine and coarse microstructures.

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Lu, Senxiang, Jian Feng, Huaguang Zhang, Jinhai Liu, and Zhenning Wu. "An Estimation Method of Defect Size From MFL Image Using Visual Transformation Convolutional Neural Network." IEEE Transactions on Industrial Informatics 15, no. 1 (January 2019): 213–24. http://dx.doi.org/10.1109/tii.2018.2828811.

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Koruk, Hasan, and Kenan Y. Sanliturk. "Detection of air leakage into vacuum packages using acoustic measurements and estimation of defect size." Mechanical Systems and Signal Processing 114 (January 2019): 528–38. http://dx.doi.org/10.1016/j.ymssp.2018.05.023.

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Lim, Byeong Soo, C. S. Jeong, Si Yon Bae, Seog Hyeon Ryu, Jeong Tae Kim, and Y. T. Keum. "Inspection of Creep Defects and Degraded Zone Using Ultrasound." Materials Science Forum 475-479 (January 2005): 4141–44. http://dx.doi.org/10.4028/www.scientific.net/msf.475-479.4141.

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The initiation and growth of internal defects usually cause the failure of long term operated structural components at high temperature. Therefore, by investigating the internal defects of material, the integrity of the system can be maintained and the unexpected failure can be prevented. The main purpose of this study is to investigate the possibility of the application of ultrasound to the measurement and estimation of the creep damage. In this study, the phased array ultrasound and backward ultrasound were employed to detect the internal defects caused by creep. Using the newly developed P92 steel, both creep and NDE ultrasound tests were performed. The results of defect inspection were checked by microstructure examination. Reliable information on the size and position of crack were obtained and successful estimation of the amount of micro-voids and their distribution proved to be obtainable by the ultrasound inspection technique. The width of the creep degraded zone was confirmed by the width of ultrasonic signal, and the severity of degradation was confirmed by ultrasonic amplitude.

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Tiwari, Kumar Anubhav, Renaldas Raisutis, Olgirdas Tumsys, Armantas Ostreika, Kestutis Jankauskas, and Julijus Jakutavicius. "Defect Estimation in Non-Destructive Testing of Composites by Ultrasonic Guided Waves and Image Processing." Electronics 8, no. 3 (March 12, 2019): 315. http://dx.doi.org/10.3390/electronics8030315.

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The estimation of the size and location of defects in multi-layered composite structures by ultrasonic non-destructive testing using guided waves has attracted the attention of researchers for the last few decades. Although extensive signal processing techniques are available, there are only a few studies available based on image processing of the ultrasonic B-scan image to extract the size and location of defects via the process of ultrasonic non-destructive testing. This work presents an image processing technique for ultrasonic B-scan images to improve the estimation of the location and size of disbond-type defects in glass fiber-reinforced plastic materials with 25-mm and 51-mm diameters. The sample is a segment of a wind turbine blade with a variable thickness ranging from 3 to 24 mm. The experiment is performed by using a low-frequency ultrasonic system and a pair of contact-type piezoceramic transducers kept apart by a 50-mm distance and embedded on a moving mechanical panel. The B-scan image acquired by the ultrasonic pitch-catch technique is denoised by utilizing features of two-dimensional discrete wavelet transform. Thereafter, the normalized pixel densities are compared along the scanned distance on the region of interest of the image, and a −3 dB threshold is applied to the locations and sizes the defects in the spatial domain.

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Ismail, Mohamed AA, Andreas Bierig, and Nader Sawalhi. "Automated vibration-based fault size estimation for ball bearings using Savitzky–Golay differentiators." Journal of Vibration and Control 24, no. 18 (July 26, 2017): 4297–315. http://dx.doi.org/10.1177/1077546317723227.

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Vibration-based fault diagnosis has been utilized as a reliable method for identifying ball bearings health since the 1970s. Recently, there has been an increased research effort to develop methods for fault quantification with the aim of estimating the fault size to allow the service life of a ball bearing to be extended beyond the detection stage. These studies have shown that the vibration signal from a localized spall (e.g. fatigue defect) in a ball bearing exhibits features corresponding to two main events, namely, the entry into and the exit from the spall. The time span between these two events is correlated with the spall size. Studies have shown that the entry into the spall is the more challenging event to identify, which often requires extensive signal processing techniques. This paper introduces an automated vibration-based technique for estimating the size of a spall in a ball bearing under axial loading conditions similar to those of linear electro-mechanical actuators. This technique is based on the extraction of the entry/exit events from the vibrational jerk, which are numerically determined from accelerometer data. The differentiation of the acceleration data to estimate jerk signal is performed using a variant of Savitzky–Golay (SG) differentiators, which provide enhancement for the detection of the entry and exit points. Sensible spall size estimations have been achieved for 24 different scenarios of fault sizes, rotor speeds and loads measured on a test rig provided by DLR (German Aerospace Center).

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35

Alshayeb, Mohammad, and Mashaan A. Alshammari. "The Effect of the Dataset Size on the Accuracy of Software Defect Prediction Models: An Empirical Study." Inteligencia Artificial 24, no. 68 (October 26, 2021): 72–88. http://dx.doi.org/10.4114/intartif.vol24iss68pp72-88.

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The ongoing development of computer systems requires massive software projects. Running the components of these huge projects for testing purposes might be a costly process; therefore, parameter estimation can be used instead. Software defect prediction models are crucial for software quality assurance. This study investigates the impact of dataset size and feature selection algorithms on software defect prediction models. We use two approaches to build software defect prediction models: a statistical approach and a machine learning approach with support vector machines (SVMs). The fault prediction model was built based on four datasets of different sizes. Additionally, four feature selection algorithms were used. We found that applying the SVM defect prediction model on datasets with a reduced number of measures as features may enhance the accuracy of the fault prediction model. Also, it directs the test effort to maintain the most influential set of metrics. We also found that the running time of the SVM fault prediction model is not consistent with dataset size. Therefore, having fewer metrics does not guarantee a shorter execution time. From the experiments, we found that dataset size has a direct influence on the SVM fault prediction model. However, reduced datasets performed the same or slightly lower than the original datasets.

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36

Selim, Hossam, Miguel Delgado Prieto, José Trull, Luis Romeral, and Crina Cojocaru. "Laser Ultrasound Inspection Based on Wavelet Transform and Data Clustering for Defect Estimation in Metallic Samples." Sensors 19, no. 3 (January 30, 2019): 573. http://dx.doi.org/10.3390/s19030573.

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Laser-generated ultrasound is a modern non-destructive testing technique. It has been investigated over recent years as an alternative to classical ultrasonic methods, mainly in industrial maintenance and quality control procedures. In this study, the detection and reconstruction of internal defects in a metallic sample is performed by means of a time-frequency analysis of ultrasonic waves generated by a laser-induced thermal mechanism. In the proposed methodology, we used wavelet transform due to its multi-resolution time frequency characteristics. In order to isolate and estimate the corresponding time of flight of eventual ultrasonic echoes related to internal defects, a density-based spatial clustering was applied to the resulting time frequency maps. Using the laser scan beam’s position, the ultrasonic transducer’s location and the echoes’ arrival times were determined, the estimation of the defect’s position was carried out afterwards. Finally, clustering algorithms were applied to the resulting geometric solutions from the set of the laser scan points which was proposed to obtain a two-dimensional projection of the defect outline over the scan plane. The study demonstrates that the proposed method of wavelet transform ultrasonic imaging can be effectively applied to detect and size internal defects without any reference information, which represents a valuable outcome for various applications in the industry.

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37

Gurau, Vladimir, and Emory De Castro. "Prediction of Performance Variation Caused by Manufacturing Tolerances and Defects in Gas Diffusion Electrodes of Phosphoric Acid (PA)–Doped Polybenzimidazole (PBI)-Based High-Temperature Proton Exchange Membrane Fuel Cells." Energies 13, no. 6 (March 13, 2020): 1345. http://dx.doi.org/10.3390/en13061345.

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The automated process of coating catalyst layers on gas diffusion electrodes (GDEs) for high-temperature proton exchange membrane fuel cells results inherently into a number of defects. These defects consist of agglomerates in which the platinum sites cannot be accessed by phosphoric acid and which are the consequence of an inconsistent coating, uncoated regions, scratches, knots, blemishes, folds, or attached fine particles—all ranging from μm to mm size. These electrochemically inactive spots cause a reduction of the effective catalyst area per unit volume (cm2/cm3) and determine a drop in fuel cell performance. A computational fluid dynamics (CFD) model is presented that predicts performance variation caused by manufacturing tolerances and defects of the GDE and which enables the creation of a six-sigma product specification for Advent phosphoric acid (PA)-doped polybenzimidazole (PBI)-based membrane electrode assemblies (MEAs). The model was used to predict the total volume of defects that would cause a 10% drop in performance. It was found that a 10% performance drop at the nominal operating regime would be caused by uniformly distributed defects totaling 39% of the catalyst layer volume (~0.5 defects/μm2). The study provides an upper bound for the estimation of the impact of the defect location on performance drop. It was found that the impact on the local current density is higher when the defect is located closer to the interface with the membrane. The local current density decays less than 2% in the presence of an isolated defect, regardless of its location along the active area of the catalyst layer.

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38

Jovic, Marko, Milovan Dimitrijevic, Ana Dimitrijevic, and Goran Stojkovic. "Analysis of reconstructive methods in surgical treatment of nasal skin defects." Vojnosanitetski pregled 73, no. 8 (2016): 723–27. http://dx.doi.org/10.2298/vsp140829052j.

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Background/Aim. Surgeons often face with the problem when selecting a reconstructive method for nasal skin defects. The aim of this study was to determine functional and aesthetic character-istics of different reconstructive methods used for skin defects in different regions of the nose. Methods. The study involved 44 patients with basocellular carcinoma in nasal area. The nasal skin was divided into four subunits: the tip, the alar lobules, the side-walls and the dorsum. The average skin defect size was 10 mm in diameter. Local flaps and full thickness skin grafts were used in the study. We analyzed the functional and esthetic results of dif-ferent reconstructive methods used for nasal defects in different regions of the nose 12 months after the surgery. Results. The study shows that different reconstructive methods produce dif-ferent functional and esthetic results in the same nasal subunits and that the same reconstructive method produces different re-sults in different nasal subunits. Conclusions. Estimation the postoperative functional and esthetic characteristics of different reconstructive methods is one of the basic preconditions of suc-cessful reconstruction.

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39

Al-Ghamd, Abdullah M., and David Mba. "A comparative experimental study on the use of acoustic emission and vibration analysis for bearing defect identification and estimation of defect size." Mechanical Systems and Signal Processing 20, no. 7 (October 2006): 1537–71. http://dx.doi.org/10.1016/j.ymssp.2004.10.013.

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Du, Bao Lei, and Qi Fei Jian. "An ISODATA Approach to the Estimation of Atomistic Definition for Continuum Stress." Materials Science Forum 909 (November 2017): 293–99. http://dx.doi.org/10.4028/www.scientific.net/msf.909.293.

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The atomic stress tensor at a given continuum point is a spatial average value of some volume near the point. Recent progresses in multiscale modeling include the dealing of the optimal number and the size of these volumes. In this paper, we motivate the application of Iterative self-organizing data analysis technique algorithm to estimate volume numbers. The size of these space averaging volumes then could be got using Gaussian mixture model. Reduced computation complexity is offered by this method. Atomistic simulations are conducted to analyze the stress of a stone-wales defect graphene sheet to validate the method. Other multiscale values could also be determined using this method.

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41

Li, Hanchao, Yating Yu, Linfeng Li, and Bowen Liu. "A Weighted Estimation Algorithm for Enhancing Pulsed Eddy Current Infrared Image in Ecpt Non-Destructive Testing." Applied Sciences 9, no. 20 (October 9, 2019): 4199. http://dx.doi.org/10.3390/app9204199.

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Non-destructive testing (NDT) plays a crucial role in large scale industrial production such as in the nuclear industry and bridge structures where even a small crack can lead to severe accidents. The pulsed eddy current infrared thermography testing method, as a classic non-destructive testing technology, is proposed to detect cracks in the presence of excitation sources that cause temperature changes in the vicinity of defects, which is higher than normal area. However, in the vicinity of the excitation sources, the temperature is higher than normal even if there is no defect. Traditional infrared image enhancing algorithms do not work efficiently when processing infrared images because the colors in the images represent the temperature. To address this, a novel algorithm is proposed in this paper. A weighted estimation algorithm is proposed because each pixel value has a strong relationship with its neighboring pixels. The value of each pixel is determined by calculating the values of its neighboring pixels with a specific step-size and the correlation coefficients between them. These coefficients are obtained by calculating the differences between the pixels. The experimental results indicated that the outline of the welding defect became significantly clearer after being processed using the proposed algorithm, which can eliminate the errors caused by the excitation source.

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42

Nunes, L. C. S., and V. M. F. Nascimento. "Estimation of internal defect size by means of radial deformations in pipes subjected to internal pressure." Thin-Walled Structures 49, no. 2 (February 2011): 298–303. http://dx.doi.org/10.1016/j.tws.2010.11.003.

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43

Parey, A., and N. Tandon. "Impact velocity modelling and signal processing of spur gear vibration for the estimation of defect size." Mechanical Systems and Signal Processing 21, no. 1 (January 2007): 234–43. http://dx.doi.org/10.1016/j.ymssp.2005.12.011.

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Stamenković, Z., and N. Stojadinović. "New defect size distribution function for estimation of chip critical area in integrated circuit yield models." Electronics Letters 28, no. 6 (1992): 528. http://dx.doi.org/10.1049/el:19920333.

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45

Stepanova, L. N., S. I. Kabanov, V. V. Chernova, and K. V. Kanifadin. "STEEL SAMPLES WELDING DEFECTS DETECTION BY ESTIMATING ENERGY OF CLUSTERS OF ACOUSTIC EMISSION SIGNALS." Kontrol'. Diagnostika, no. 256 (2019): 4–11. http://dx.doi.org/10.14489/td.2019.10.pp.004-011.

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Acoustic emission (AE) detection of 5005005 mm size St3 steel samples welding defects. The informative parameters of AE signals recorded during welding with inserts of titanium and aluminum inserted into the root of the weld are analyzed. AE-signals recording was performed by welding diagnostic unit with automatically changing “floating” selection threshold. For coordinates of defects estimation clustering was performed by digital form and AE signals parameters. A comparative analysis of the clustering results was performed for each cluster. In this case, the total count of AE signals, their energy, and threshold levels were set, which were determined in accordance with the proposed algorithm. The degree of danger of defects in the weld was monitored by exceeding AE signal energy threshold level. If the AE signal had a second energy peak and when it exceeds the energy selection thresholds, the weld was rejected. It was experimentally shown that the titanium insert was a dangerous defect when the threshold energy level was exceeded, which was detected both with a high total count of AE signals and with a small number of recorded signals. In accordance with the proposed method, when introducing an aluminum insert into the weld, the defect was not considered dangerous.

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Hope, William W., Zachary F. Williams, James W. Rawles, W. Borden Hooks, Thomas V. Clancy, and Frederic E. Eckhauser. "Rationale and Technique for Measuring Abdominal Wall Tension in Hernia Repair." American Surgeon 84, no. 9 (September 2018): 1446–49. http://dx.doi.org/10.1177/000313481808400947.

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We describe a method to measure abdominal wall tension during hernia surgery and evaluate a possible correlation between hernia defect width and abdominal wall tension. After Institutional Review Board approval and informed consent, a prospective trial to measure intra-abdominal tension was undertaken (May 2013 through March 2017). Tension measurements were obtained using tensiometers. Total tension, hernia defect width, and surgeon's estimation of tension were recorded. Correlation between defect width and total abdominal wall tension was assessed using multivariate analysis and a multiple linear regression analysis. An r-squared value > 0.6 was considered significant. Fifty-nine patients underwent hernia repair with concomitant tension measurements obtained at surgery. The average patient age was 61 years (range 29–81 years), 85 per cent were white, and 56 per cent female. The average total tension was 6.7 pounds (range 0.2–22 pounds) and average defect width was 8.6 cm (range 2–25 cm). The surgeon rated the fascia to be excellent in 15 per cent, good in 58 per cent, and fair in 27 per cent. The average estimation of tension by the surgeon was 5 pounds (range 2–10 pounds). We found no correlation between hernia defect size and total abdominal wall tension and no correlation between the surgeon-estimated tension and objectively measured tension. We found no correlation between the width of the hernia defect and tension associated with approximating the midline. Further study regarding the practicality and usefulness of abdominal wall tension measurements during hernia surgery is needed.

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P.A., Nikitin, Nudnov N.V., Znamenskiy I.A., Azimov R.H., Kharina D.S., and Kudryavtsev A.D. "ESTIMATION OF CORRECT MEASUREMENT OF THE TITANIUM RETAINED IMPLANTS AREA BY CT EXPERIMENTAL MODEL." Global problems of modernity 3, no. 1 (April 20, 2022): 59–63. http://dx.doi.org/10.26787/nydha-2713-2048-2022-3-1-59-63.

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Annotation: This article presents the results of evaluating the measurement of the area of titanium mesh implants using computed tomography (CT) data based on the use of an experimental model. Hernioplasty using mesh implants is a modern method of treating hernias of the anterior abdominal wall. The most common complication of hernia surgery is hernia recurrence. The main reason for the development of recurrence is the discrepancy between the size of the implant and the hernial defect, which may occur due to a decrease in the size of the mesh after its installation. CT can be used to assess changes in mesh size. The study showed that the dimensions obtained because of non-invasive measurement of the mesh implant by CT did not significantly differ from the dimensions of the implant obtained intraoperatively. Thus, CT is a highly effective method for assessing the size of titanium mesh implants and can be used in clinical practice.

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Li, Zhe, Yongpeng Xu, and Xiuchen Jiang. "Pattern Recognition of DC Partial Discharge on XLPE Cable Based on ADAM-DBN." Energies 13, no. 17 (September 3, 2020): 4566. http://dx.doi.org/10.3390/en13174566.

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Pattern recognition of DC partial discharge (PD) receives plenty of attention and recent researches mainly focus on the static characteristics of PD signals. In order to improve the recognition accuracy of DC cable and extract information from PD waveforms, a modified deep belief network (DBN) supervised fine-tuned by the adaptive moment estimation (ADAM) algorithm is proposed to recognize the four typical insulation defects of DC cable according to the PD pulse waveforms. Moreover, the effect of the training sample set size on recognition accuracy is analyzed. Compared with naive Bayes (NB), K-nearest neighbor (KNN), support vector machine (SVM), and back propagation neural networks (BPNN), the ADAM-DBN method has higher accuracy on four different defect types due to the excellent ability in terms of the feature extraction of PD pulse waveforms. Moreover, the increase of training sample set size would lead to the increase of recognition accuracy within a certain range.

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Petersen, Dick, Carl Howard, and Zebb Prime. "Varying stiffness and load distributions in defective ball bearings: Analytical formulation and application to defect size estimation." Journal of Sound and Vibration 337 (February 2015): 284–300. http://dx.doi.org/10.1016/j.jsv.2014.10.004.

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50

Moazen-ahmadi, Alireza, and Carl Q. Howard. "A defect size estimation method based on operational speed and path of rolling elements in defective bearings." Journal of Sound and Vibration 385 (December 2016): 138–48. http://dx.doi.org/10.1016/j.jsv.2016.09.014.

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