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Journal articles on the topic 'Defects propagation'

Author: Grafiati

Published: 8 June 2024

Last updated: 31 July 2025

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1

Salim, M. N., M. N. M. Khairy, and T. Hayashi. "Effect of Oval Defect on Propagation of Fundamental Lamb Wave." Applied Mechanics and Materials 833 (April 2016): 49–58. http://dx.doi.org/10.4028/www.scientific.net/amm.833.49.

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Complicated Lamb wave propagation in structures can cause a misinterpretation in defect location and sizing during nondestructive inspections. A visualization of Lamb wave interactions with oval defects was carried out in our study to investigate the phenomenon of fundamental Lamb wave interaction around defect by using a reduced model of plate in ABAQUS. The visualized wave propagations with oval shape of through defects in plates demonstrated different patterns of wave interactions for the symmetric and anti-symmetric modes. The results also visualized the mode conversions around defects whi

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2

Wang, Shang, Wei Qiang Wang, Ming Da Song, and Hao Zhang. "The Fatigue and Fracture Analysis of Steam Turbine Rotor Shafts Containing Defects." Key Engineering Materials 795 (March 2019): 254–61. http://dx.doi.org/10.4028/www.scientific.net/kem.795.254.

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In this study, the assessment and calculation methods for the crack propagation life of steam turbine rotor shafts containing defects are presented. The analytic methods for estimating the average stress and the alternating stress amplitude of the steam turbine rotor shafts are introduced. The defects on/in the rotor shafts were regularized by the method of fracture mechanics, and the high cycle fatigue crack propagation life and low cycle fatigue crack propagation life of the rotor shafts are estimated from Paris formula. Taking the 60MW turbine rotor shafts containing an initial surface defe

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Huang, Yunqing, and Jichun Li. "Total Reflection and Cloaking by Triangular Defects Embedded in Zero Index Metamaterials." Advances in Applied Mathematics and Mechanics 7, no. 2 (2015): 135–44. http://dx.doi.org/10.4208/aamm.2014.m659.

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AbstractIn this work, we investigate wave propagation through a zero index meta-material (ZIM) waveguide embedded with triangular dielectric defects. We provide a theoretical guidance on how to achieve total reflection and total transmission (i.e., cloaking) by adjusting the defect sizes and/or permittivities of the defects. Our work provides a systematical way in manipulating wave propagation through ZIM in addition to the widely studied dielectric defects with cylindrical and rectangular geometries.

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Yu, Shuisheng, Leilei Niu, Jin Chen, Yawei Wang, and Honghao Yang. "Study on Bond Defect Detection in Grouted Rock Bolt Systems under Pullout Loads." Advances in Materials Science and Engineering 2022 (August 31, 2022): 1–9. http://dx.doi.org/10.1155/2022/3282211.

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In grouted rock bolt systems, bond defects often occur, which seriously affects the safety of rock mass structures. Therefore, in this study, based on the existence of bond defects, laboratory tests were conducted to detect the location and length of bond defects and study the guided wave propagation in grouted rock bolt systems under different pullout loads. The guided wave signal was analysed in the time domain and frequency domain. In addition to the laboratory test, a numerical simulation of the effect of different bond defect locations on ultrasonic guided wave propagation in rock bolts w

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Basmaci, Ayse. "The Behavior of Electromagnetic Wave Propagation in Photonic Crystals with or without a Defect." Applied Computational Electromagnetics Society 36, no. 6 (2021): 632–41. http://dx.doi.org/10.47037/2020.aces.j.360603.

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In this study, the electromagnetic wave propagation behavior of two-dimensional photonic crystal plates with a defect is investigated. For this purpose, the partial differential equation for the electromagnetic wave propagation in various photonic crystal plates containing a defect or not is obtained by using Maxwell’s equations. The defect is also defined in the electromagnetic wave propagation equation appropriately. In order to solve the electromagnetic wave propagation equation, the finite differences method is used. The material property parameters of the photonic crystal plates are deter

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6

Zhu, Rui, Yonghui Liu, Xingyue Nie, Qingqing Xiao, Jingpu Liang, and Dongfeng Cao. "Compressive Failure and Dual-Defect Coupling Effects of Open-Hole Composite Laminates with Drilling-Induced Delamination." Materials 18, no. 12 (2025): 2790. https://doi.org/10.3390/ma18122790.

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This study investigates the influence of drilling-induced delamination damage on the compressive mechanical behavior of open-hole carbon fiber-reinforced composite laminates and explores the failure mechanisms under dual-defect coupling effects. Specimens with circular delamination defects of varying sizes were fabricated by embedding polytetrafluoroethylene (PTFE) films during the layup process. Ultrasonic C-scan and digital image correlation (DIC) techniques were used to monitor delamination propagation and deformation behavior. A cohesive zone-based numerical model was developed and validat

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Huang, Chen, Zong-Xian Zhang, Adeyemi Aladejare, Xianbo Guan, Bingbing Yu, and Liyun Yang. "The Effect of Preloaded Compressive Stress and Curvature of Defect on Blast-Induced Fracture Behavior by Caustic and Numerical Models." Mathematics 11, no. 21 (2023): 4532. http://dx.doi.org/10.3390/math11214532.

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In this study, the effects of preloaded uniaxial compressive stress and defect (prefabricated by laser cutting) curvature on blast-induced cracks and stress wave propagation were investigated in polymethyl methacrylate (PMMA) specimens using caustics theory. Based on the mathematical relationship between stress and optics, the fracture behavior (the propagation path, dynamic stress intensity factors (DSIFs), propagation velocity, initiation angle of the main crack, and damage degree between the defect and the blasthole) was calculated and analyzed quantitatively. The results show that the prel

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8

Cao, Andong, Zhen Zhang, and Qian Li. "Frequency shifting of transmitted ultrasound in thick composites containing fiber wrinkles and its application in non-destructive evaluation." Journal of the Acoustical Society of America 154, no. 4_supplement (2023): A246. http://dx.doi.org/10.1121/10.0023434.

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Thick composite structures are prone to defects such as fiber wrinkles and voids during manufacturing. It is challenging to accurately evaluate the forming quality of the structures using conventional ultrasonic inspection, due to the coupling effects between time-frequency features of ultrasound and mixed-type defects. Propagation behaviors of through-thickness transmitted ultrasound in thick composites with fiber wrinkles, voids and no defects were comparatively investigated by both simulation and experiment in this study. Influence of out-of-plane fiber wrinkles on the ultrasonic frequency

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Bultel, Yann, Corine BAS, Florence Dubelley, Fabrice Micoud, Sébastien Rosini, and Christine Nayoze-Coynel. "Anode Defects’ Propagation in Polymer Electrolyte Membrane Fuel Cells Stack." ECS Meeting Abstracts MA2023-02, no. 38 (2023): 1835. http://dx.doi.org/10.1149/ma2023-02381835mtgabs.

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Reliability and durability are key considerations to successfully deploy Proton Exchange Membrane Fuel Cells (PEMFCs). Defects induced by manufacturing processes and fuel cell operating conditions may shorten the lifetime of PEMFC due to membrane electrode assembly (MEA) components degradations. If the degradation mechanisms occurring along ageing are now well-known, the propagation of these defects to other materials or to other locations in the stack was poorly investigated in the literature. Recently, we investigated a defect-propagation in MEA via accelerated stress tests combining load an

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10

Erofeev, V. I., A. V. Leonteva, and A. V. Shekoyan. "DISPERSION OF LONGITUDINAL WAVES PROPAGATING IN MATERIALS WITH POINT DEFECTS." PNRPU Mechanics Bulletin, no. 5 (December 6, 2023): 26–35. http://dx.doi.org/10.15593/perm.mech/2023.5.03.

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The paper investigates the propagation of harmonic waves in materials with point defects. The problem is described by a system of differential equations, which includes a dynamic equation of the theory of elasticity and kinetic equations of defect densities tak-ing into account the mutual influence of defects and a propagating wave, as well as mutu-al recombination of defects. We consider both limit cases, materials with one type of point defects (vacancies, interstitials), and the general case if the material contains both types of point defects (vacancies and interstitials). We analyzed the

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11

Yilmaz, Ayca, Dilek Helvacioglu-Yigit, Cansu Gur, et al. "Evaluation of Dentin Defect Formation during Retreatment with Hand and Rotary Instruments: A Micro-CT Study." Scanning 2017 (2017): 1–7. http://dx.doi.org/10.1155/2017/4868603.

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The purpose of this study was to compare the incidence and longitudinal propagation of dentin defects after gutta-percha removal with hand and rotary instruments using microcomputed tomography. Twenty mandibular incisors were prepared using the balanced-force technique and scanned in a 19.9 μm resolution. Following filling with the lateral compaction technique, gutta-percha was removed with ProTaper Universal Retreatment (PTUR) or hand instruments. After rescanning, a total of 24,120 cross-sectional images were analyzed. The numbers, types, and longitudinal length changes of defects were recor

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12

Xie, Mingjiang, Yifei Wang, Weinan Xiong, Jianli Zhao, and Xianjun Pei. "A Crack Propagation Method for Pipelines with Interacting Corrosion and Crack Defects." Sensors 22, no. 3 (2022): 986. http://dx.doi.org/10.3390/s22030986.

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Corrosion and crack defects often exist at the same time in pipelines. The interaction impact between these defects could potentially affect the growth of the fatigue crack. In this paper, a crack propagation method is proposed for pipelines with interacting corrosion and crack defects. The finite element models are built to obtain the Stress Intensity Factors (SIFs) for fatigue crack. SIF interaction impact ratio is introduced to describe the interaction effect of corrosion on fatigue crack. Two approaches based on extreme gradient boosting (XGBoost) are proposed in this paper to predict the

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13

Lim, Seong-Sik, Je-Pyo Hong, Minki Kim, et al. "Study on Rolling Defects of Al-Mg Alloys with High Mg Content in Normal Rolling and Cross-Rolling Processes." Materials 16, no. 18 (2023): 6260. http://dx.doi.org/10.3390/ma16186260.

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This study investigated defect formation and strain distribution in high-Mg-content Al-Mg alloys during normal rolling and cross-rolling processes. The finite element analysis (FEA) revealed the presence of wave defects and strain localization-induced zipper cracks in normal cold rolling, which were confirmed by the experimental results. The concentration of shear strain played a significant role in crack formation and propagation. However, the influence of wave defects was minimal in the cross-rolling process, which exhibited a relatively uniform strain distribution. Nonetheless, strain conce

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14

Wei, Chihang, and Zhihuan Song. "Real-Time Forecasting of Subsurface Inclusion Defects for Continuous Casting Slabs: A Data-Driven Comparative Study." Sensors 23, no. 12 (2023): 5415. http://dx.doi.org/10.3390/s23125415.

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Subsurface inclusions are one of the most common defects that affect the inner quality of continuous casting slabs. This increases the defects in the final products and increases the complexity of the hot charge rolling process and may even cause breakout accidents. The defects are, however, hard to detect online by traditional mechanism-model-based and physics-based methods. In the present paper, a comparative study is carried out based on data-driven methods, which are only sporadically discussed in the literature. As a further contribution, a scatter-regularized kernel discriminative least

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15

Valentini, M., S. K. Serkov, D. Bigoni, and A. B. Movchan. "Crack Propagation in a Brittle Elastic Material With Defects." Journal of Applied Mechanics 66, no. 1 (1999): 79–86. http://dx.doi.org/10.1115/1.2789172.

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A two-dimensional asymptotic solution is presented for determination of the trajectory of a crack propagating in a brittle-elastic, isotropic medium containing small defects. Brittleness of the material is characterized by the assumption of the pure Mode I propagation criterion. The defects are described by Po´lya-Szego¨ matrices, and examples for small elliptical cavities and circular inclusions are given. The results of the asymptotic analysis, which agree well with existing numerical solutions, give qualitative description of crack trajectories observed in brittle materials with defects, su

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16

Jiang, Yin Fang, Zhen Ning Guo, Yong Qi Yan, and Qin Huang. "Study on Inside and Outside Circumferential Defects of Pipes and Ultrasonic Guided Wave." Advanced Materials Research 460 (February 2012): 411–14. http://dx.doi.org/10.4028/www.scientific.net/amr.460.411.

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The difference between inside circumferential defects and outside circumferential defects was proved using the theory of reflection waves, the course of propagation and reflection from inside circumferential defects and outside circumferential defects in steel pipes was simulated with L(0,2) mode by the numerical simulation program ANSYS, and the curves of the reflection waves were obtained. The investigation indicated that the relationship between reflection coefficient of each kind of circumferential defects and the circumference of the defects was linear; in additional, it was found that th

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17

THATCHER, M. J., and M. J. MORGAN. "BIREFRINGENT ELECTROWEAK DEFECTS." International Journal of Modern Physics A 17, no. 14 (2002): 1953–64. http://dx.doi.org/10.1142/s0217751x02010583.

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In this paper we examine the propagation of electromagnetic waves through electroweak textures and W-strings. The photon is associated with a negative mass squared term as a consequence of its coupling to the intermediate vector bosons from which the electroweak defect is constructed. The photon pseudo-mass depends on the polarization of the photon and results in electroweak defects exhibiting birefringent properties. We calculate the effective refractive index and birefringence length scale. The cosmological implications of birefringent electroweak defects are discussed.

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18

Fang, Chunhua, Junjie Lv, Ziheng Pu, Peng Li, Tian Wu, and Tao Hu. "Electromagnetic Ultrasonic Shear-Horizontal Wave to Detect Corrosion Defect of Flat Steel for Grounding Device of Transmission Pole Tower." Applied Sciences 13, no. 12 (2023): 6947. http://dx.doi.org/10.3390/app13126947.

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Detecting defects in grounded flat steel is essential for ensuring the safety and reliability of transmission tower grounding devices. However, traditional inspection methods, such as physical excavation and verification, are costly and time-consuming. This paper proposes a corrosion defect detection method for flat steel transmission tower grounding devices based on electromagnetic ultrasonic SH waves. In addition, using commercial software, a three-dimensional finite element simulation model of grounded flat steel with simulated pitting corrosion defects is constructed. The specified displac

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19

Liang, Peifeng, Andrei Kotousov, and Ching Tai Ng. "Propagation, Scattering and Defect Detection in a Circular Edge with Quasi-Edge Waves." Applied Sciences 14, no. 22 (2024): 10672. http://dx.doi.org/10.3390/app142210672.

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Structural components with curved edges are common in many engineering designs. Fatigue cracks, corrosion and other types of defects and mechanical damage often initiate from (or are located close to) edges. Damage and defect detection in the presence of complex geometry represents a significant challenge for non-destructive testing (NDT). To address this challenge, this paper investigates the fundamental mode of the quasi-symmetric edge-guided wave (QES0) propagating along a curved edge, as well as its scattering characteristics in the presence of different types of edge defects. The finite e

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20

Hou, Ning, Li Zhou, Shu Tao Huang, and Li Fu Xu. "Finite Element and Experimental Analysis of Edge Defects Formation during Orthogonal Cutting of SiCp/Al Composites." Advanced Materials Research 500 (April 2012): 146–51. http://dx.doi.org/10.4028/www.scientific.net/amr.500.146.

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In this paper, a finite element method was used to dynamically simulate the process of the edge defects formation during orthogonal cutting SiCp/Al composites. The influence of the cutting speed, cutting depth and rake angle of the PCD insert on the size of the edge defects have been investigated by using scanning electron. According to the simulated results, it can be provided that the cutting layer material has an effect on transfer stress and hinder the chip formation in the critical transition stage, and the critical transition point and distance are defined in this stage. The negative she

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21

Ishikawa, Yukari, Koji Sato, Yoshihiro Okamoto, Noritaka Hayashi, Yong Zhao Yao, and Yoshihiro Sugawara. "Dislocation Formation in Epitaxial Film by Propagation of Shallow Dislocations on 4H-SiC Substrate." Materials Science Forum 717-720 (May 2012): 383–86. http://dx.doi.org/10.4028/www.scientific.net/msf.717-720.383.

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Shallow defects, which were induced by mechanical treatment, on 4H-SiC wafers were investigated. The density and the distribution in depth of shallow defects on the wafers were depended on wafer venders. Most of serious defects such as dislocation array (DA), triangular stacking fault (TRSF) and triangular defect (TRD) in epitaxial film were demonstrated to be caused by shallow dislocations on the surface of the wafers. Revised mechanical polish can reduce the densities of DA, TRSF and TRD in epitaxial film.

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22

Song, Shi Quan, Hua Dong Xu, and Li Hai Wang. "Application of Ultrasonic Wave and Resistograph for Nondestructive Testing of Defects in Standing Trees." Applied Mechanics and Materials 48-49 (February 2011): 265–69. http://dx.doi.org/10.4028/www.scientific.net/amm.48-49.265.

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In order to carry out non-destructive testing on standing trees, explore the propagation characteristics and the influence factors of the ultrasonic wave spreading in the standing trees. Take simon poplar as the research object, Resistograph were employed to test 30 sample (simon polar) standing trees and it gave a preliminary estimate of the internal defects in the samples, and RSM-SYS5 ultrasonic device were employed to test the ultrasonic propagation velocity spreading in simon poplar standing trees, with the statistics of the ultrasonic propagation velocity spreading separately in the heal

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CASTREJON-M, C., V. GRIMALSKY, S. KOSHEVAYA, and A. ZAMUDIO-LARA. "PROPAGATION OF TRANSVERSELY BOUNDED NONLINEAR ELECTROMAGNETIC PULSES THROUGH PERIODIC MEDIA." Journal of Nonlinear Optical Physics & Materials 21, no. 02 (2012): 1250022. http://dx.doi.org/10.1142/s0218863512500221.

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Nonlinear propagation of optical pulses of finite transverse widths through periodic structures with and without defects is investigated numerically and the subject of investigation is a stack of alternating linear and cubically nonlinear layers of submicron thicknesses is considered. The simulations are based on a modified equation for the pulse envelope and modified boundary conditions where both the diffraction and possible focusing of the pulse are taken into account. The simulations demonstrate an essential influence of defects within the periodic structure on the nonlinear propagation of

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Wei, Xiwen, Liping Sun, Quansheng Sun, Shuzheng Xu, Hongjv Zhou, and Chunxiao Du. "Propagation velocity model of stress wave in longitudinal section of tree in different angular directions." BioResources 14, no. 4 (2019): 8904–22. http://dx.doi.org/10.15376/biores.14.4.8904-8922.

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In order to detect the size and shape of defects inside wood, a propagation velocity model of stress wave in the longitudinal section of trees in different direction angles was proposed and evaluated. The propagation velocity model was established through theoretical analysis. Four representative tree species in the northeast region of China were taken as test samples. The propagation velocity of stress wave in the longitudinal section of trees in different directions was measured using a nondestructive testing instrument. The corresponding regression model was obtained, which was in good agre

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Yao, Zong Jian, Gui Lan Yu, Yue Sheng Wang, and Jian Bao Li. "Flexural Vibration in a Ternary Locally Resonant Phononic Crystal Thin Plate with Defects." Advanced Materials Research 150-151 (October 2010): 1282–85. http://dx.doi.org/10.4028/www.scientific.net/amr.150-151.1282.

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The improved supercell plane wave expansion method is applied to theoretically study the propagation of flexural waves in a ternary locally resonant phononic crystal thin plate with a point defect and linear defects. The thin concrete plate composed of a square array of steel cylinders hemmed around by rubber is considered here. Absolute band gaps in low frequency are obtained. For the point defect, the defect mode is localized around the defect, and the magnitude of the resonant defect mode is strongly dependent on the defect filling fraction, mass density and Young’s modulus of the defect cy

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Ishikawa, Masashi, Sou Ishihara, Hideo Nishino, et al. "Relationship between Inspection Time and Frequency Components of Input and Reflected Thermal Waves in Active Thermographic Non-Destructive Inspection." Proceedings 27, no. 1 (2019): 16. http://dx.doi.org/10.3390/proceedings2019027016.

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Experiments and numerical simulations for a carbon fiber reinforced plastic specimen were performed to investigate the relationship between the time required for detecting subsurface defects and the frequency components of the thermal waves propagating within the specimen. Experimental results showed that the required inspection time was shortened by increasing the frequency of the input thermal wave. However, if the attenuation during thermal wave propagation is large enough to render the detection of the thermal wave reflected at the subsurface defect impossible, the inspection time exceeds

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Chang, Wen Yeau. "Application of Back Propagation Neural Network for Partial Discharge Pattern Recognition." Applied Mechanics and Materials 577 (July 2014): 511–14. http://dx.doi.org/10.4028/www.scientific.net/amm.577.511.

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This paper proposes a pattern recognition approach based on the back propagation (BP) neural network for identifying insulation defects of high-voltage electrical apparatus arising from partial discharge (PD). Pattern recognition of PD is used for identifying defects causing the PD, such as internal discharge, external discharge, corona, etc. This information is vital for estimating the harmfulness of the discharge in the insulation. Since an insulation defect, such as one resulting from PD, would have a corresponding particular pattern, pattern recognition of PD is significant means to discri

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Hempel, Martin, Jens W. Tomm, Ute Zeimer, and Thomas Elsaesser. "Defect Propagation in Broad-Area Diode Lasers." Materials Science Forum 725 (July 2012): 101–4. http://dx.doi.org/10.4028/www.scientific.net/msf.725.101.

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A simple model is presented for the propagation of macroscopic defects within the quantum well (QW) plane of broad-area high power diode lasers. The catastrophic optical damage (COD) effect is considered the mechanism for creating an initial damage site and further development of defect pattern. The relations between the parameters used in the model and the actual physical properties of the semiconductor materials are discussed. Experimentally observed damage patterns are well described.

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Tanaka, Keisuke, and Yoshiaki Akiniwa. "Short Fatigue-Crack Growth from Crack-like Defects under Completely Reversed Loading Predicted Based on Cyclic R-Curve." Materials 17, no. 18 (2024): 4484. http://dx.doi.org/10.3390/ma17184484.

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Understanding short fatigue-crack propagation behavior is inevitable in the defect-tolerant design of structures. Short cracks propagate differently from long cracks, and the amount of crack closure plays a key role in the propagation behavior of short cracks. In the present paper, the buildup of fatigue-crack closure due to plasticity with crack extension from crack-like defects is simulated with a modified strip yield model, which leaves plastic stretch in the wake of the advancing crack. Crack-like defects are assumed to be closure-free and do not close even under compression. The effect of

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Dong, Jiwei, and Yaohua Gong. "Influence of void defects on progressive tensile damage of three-dimensional braided composites." Journal of Composite Materials 52, no. 15 (2017): 2033–45. http://dx.doi.org/10.1177/0021998317737829.

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A meso-finite element model with random voids in matrix is developed to simulate the tensile progressive damage of three-dimensional braided composites. A stiffness degradation method for generating the random void defect element in finite element method is presented. Proper criteria are adopted as initial damage of components, and stiffness degradation is implemented for damage propagation. The tensile strengths are predicted from calculated stress–strain curves. From simulation, void defects in matrix make the redistribution of micro-stress and accelerate the damage propagation of three-dime

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Wang, Jian, Xing Guo, Yanqin Xun, Junzuo Liu, Xin Guo, and Ya Li. "Longitudinal Wave Defect Detection Technology Based on Ablation Mechanism." Photonics 11, no. 9 (2024): 805. http://dx.doi.org/10.3390/photonics11090805.

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For laser ultrasound in the thermoelastic mechanism, excitation of ultrasonic body wave signal is weak, it is not easy to realize the detection of deep defects inside the workpiece. While the ablation mechanism produces a high and practical ultrasonic signal-to-noise ratio, this paper is based on the generation mechanism of laser ablation excitation of ultrasonic waves, the establishment of laser ultrasound in the ablation mechanism in the aluminum plate excitation and propagation of ultrasonic numerical model, through the solution, obtained the ultrasonic acoustic field map, discussed the abl

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Sevost'yanov, P. A. "MODELLING OF AGING OF THREADS AND FIBRES WITH COMPUTER SIMULATION METHODS." Technologies & Quality, no. 4 (2019): 36–39. http://dx.doi.org/10.34216/2587-6147-2019-4-46-36-39.

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The article proposes an algorithm for computer statistical simulation of the formation and development of areas of defects and aging in one-dimensional fibrous materials of arbitrary finite length. The software implementation of the algorithm in the Matlab environment allowed to obtain a visual picture of the aging regions propagation dynamics, taking into account the probabilistic nature of the occurrence and propagation of defects. The model combines factors affecting the location of defect sources along the threads and fibres length, the violation intensity of the fibrous material propertie

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Berteaux, Olivier, Roger Valle, Monique Raffestin, Marc Thomas, and G. Henaff. "An Investigation of Fracture Origins in Heat-Treated Ti₄₉Al₄₇Cr₂Nb₂ Powder Compacts." Materials Science Forum 638-642 (January 2010): 1422–27. http://dx.doi.org/10.4028/www.scientific.net/msf.638-642.1422.

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The fatigue behaviour of a powder-metallurgy (PM) + heat-treated Ti49Al47Cr2Nb2 alloy is investigated using detailed SEM characterization. Based on the results of comparative static and cyclic loadings at RT, the fracture origins for the different test specimens is investigated. Conventional fractographic analyses revealed that internal structural defects inherent to powder metallurgy such as compaction defects, porosities and non-metallic inclusions can promote crack initiation. However, the fracture surface of test specimens is markedly affected by the microstructure, which is indicative of

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Wagih, Ahmed, Hassan A. Mahmoud, Ran Tao, and Gilles Lubineau. "Towards Tough Thermoplastic Adhesive Tape by Microstructuring the Tape Using Tailored Defects." Polymers 15, no. 2 (2023): 259. http://dx.doi.org/10.3390/polym15020259.

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This paper presents a strategy towards achieving thermoplastic adhesive tapes with high toughness by microstructuring conventional tapes using tailored defects. Toughened tape was manufactured using two layers of a conventional tape where the bondline between the two adhesive layers was microstructured by embedding tailored defects with specific size and gap between them using PTFE film. Mode I toughness of the toughened tape was characterized experimentally. A high-fidelity finite element model was implemented to describe the toughening mechanisms using double cantilever beam simulations and

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Yang, Jing Gang, Yong Yong Jia, Ke Zhao, and Shan Gao. "Simulation Study of Partial Discharge UHF Wave Transmission Characteristic in GIS Typical Structure." Applied Mechanics and Materials 672-674 (October 2014): 787–92. http://dx.doi.org/10.4028/www.scientific.net/amm.672-674.787.

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Defects inside the gas-insulated switchgear (GIS) will produce ultra-high frequency (UHF) electromagnetic waves. The waves will be affected by the shell of GIS when propagating inside the GIS cavity. In the 0-3GHz frequency range, propagation characteristic of electromagnetic which is excited by partial discharge in GIS is simulated based on the method of finite difference time domain (FDTD). This paper designs the GIS simulation models with and without insulator according to the size of a 220kV single phase GIS bus and sets a metal protrusion defect on the bus as the PD source. The transmissi

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Dlhý, Pavol, Jan Poduška, Michael Berer, et al. "Crack Propagation Analysis of Compression Loaded Rolling Elements." Materials 14, no. 10 (2021): 2656. http://dx.doi.org/10.3390/ma14102656.

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The problem of crack propagation from internal defects in thermoplastic cylindrical bearing elements is addressed in this paper. The crack propagation in these elements takes place under mixed-mode conditions—i.e., all three possible loading modes (tensile opening mode I and shear opening modes II and III) of the crack are combined together. Moreover, their mutual relation changes during the rotation of the element. The dependency of the stress intensity factors on the crack length was described by general parametric equations. The model was then modified by adding a void to simulate the prese

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Wang, Ying, Wenhui Zhang, Xu Pan, and Yuqian Zheng. "Experimental Study on Fatigue Crack Propagation of High-Strength Steel Wire with Initial Defects for Bridge Cables." Applied Sciences 10, no. 12 (2020): 4065. http://dx.doi.org/10.3390/app10124065.

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In order to study the effect of initial defects on fatigue crack propagation law, a test method to identify fatigue crack propagation rate and path based on load waveform variation was presented, and a new test device was designed to apply fatigue pulsation loads to multiple wires for bridge cables simultaneously in this paper. To simplify the corrosion defect formation process, a machine-cut notch was used to describe the initial defect on the steel wire surface. Firstly, fatigue crack propagation tests were conducted on the surface notched steel wire specimens. By using crack front marking t

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Uvaysov, S. U., N. T. Luu, C. D. Nguyen, Th H. Vo, and A. V. Dolmatov. "Detection of defects in printed circuit boards by the acoustic emission method." Russian Technological Journal 12, no. 1 (2024): 15–29. http://dx.doi.org/10.32362/2500-316x-2024-12-1-15-29.

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Objectives. Defects in the form of layering may occur during lamination in the production of multilayer printed circuit boards (MPCB). These defects cannot be detected by optical and electrical methods of output control. However, they can lead to breaches of the mechanical mode of operation and failures while running radioelectronic devices. In order to detect such defects, the acoustic emission (AE) method is proposed. This is based on the occurrence and propagation of acoustic waves in MPCBs caused by the presence of defects. The aim of this study is to investigate the possibility of using t

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Raišutis, Renaldas, Olgirdas Tumšys, Egidijus Žukauskas, Vykintas Samaitis, Lina Draudvilienė, and Audrius Jankauskas. "An Inspection Technique for Steel Pipes Wall Condition Using Ultrasonic Guided Helical Waves and a Limited Number of Transducers." Materials 16, no. 15 (2023): 5410. http://dx.doi.org/10.3390/ma16155410.

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This research utilizes Ultrasonic Guided Waves (UGW) to inspect corrosion-type defects in steel pipe walls, providing a solution for hard-to-reach areas typically inaccessible by traditional non-destructive testing (NDT) methods. Fundamental helical UGW modes are used, allowing the detection of defects anywhere on the pipe’s circumference using a limited number of transducers and measurements on the upper side of the pipe. Finite element (FE) modeling and experiments investigated generating and receiving UGW helical waves and their propagation through varying corrosion-type defects. Defect det

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Ferro, Gabriel, Olivier Kim-Hak, Jean Lorenzzi та ін. "On the Mechanism of Twin Boundary Elimination in 3C-SiC(111) Heteroepitaxial Layers on α-SiC Substrates". Materials Science Forum 679-680 (березень 2011): 71–74. http://dx.doi.org/10.4028/www.scientific.net/msf.679-680.71.

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This paper deals with the formation and propagation of twin boundaries (TBs) inside 3C-SiC layers grown heteroepitaxially on -SiC substrate. The equivalent probability of nucleating 60° rotated 3C islands on such substrate lead to the systematic formation of TB upon coalescence of these islands. Elimination of these defects should occur by bending of the propagation direction. Bending through incoherent TBs is usually encountered during both VLS and CVD growth and it generates crystalline defects due to high built-in energy. One would prefer coherent TBs, formed by two-by-two annihilation of

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Anthony, Denis M., Evor L. Hines, David A. Hutchins, and J. T. Mottram. "Ultrasound Tomography Imaging of Defects Using Neural Networks." Neural Computation 4, no. 5 (1992): 758–71. http://dx.doi.org/10.1162/neco.1992.4.5.758.

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Simulations of ultrasound tomography demonstrated that artificial neural networks can solve the inverse problem in ultrasound tomography. A highly simplified model of ultrasound propagation was constructed, taking no account of refraction or diffraction, and using only longitudinal wave time of flight (TOF). TOF data were used as the network inputs, and the target outputs were the expected pixel maps, showing defects (gray scale coded) according to the velocity of the wave in the defect. The effects of varying resolution and defect velocity were explored. It was found that defects could be ima

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Baek, Sooyeon, and Kyung Cheol Choi. "P‐166: Interface Defect Engineering Strategy to Enhance Flexibility of Thin Film Encapsulation by Inhibiting Crack Propagation." SID Symposium Digest of Technical Papers 55, no. 1 (2024): 2019–21. http://dx.doi.org/10.1002/sdtp.17994.

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This study explores Thin Film Encapsulation, highlighting its impressive resistance to crack propagation achieved by intentionally introducing defects between two distinct inorganic materials. Through strategic interface defect engineering, we have successfully reinforced the encapsulation's robustness, contributing to its enhanced performance and durability.

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Minnetyan, L., and C. C. Chamis. "Damage Tolerance of Large Shell Structures." Journal of Pressure Vessel Technology 121, no. 2 (1999): 188–95. http://dx.doi.org/10.1115/1.2883685.

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Progressive damage and fracture of large shell structures is investigated. A computer model is used for the assessment of structural response, progressive fracture resistance, and defect/damage tolerance characteristics. Critical locations of a stiffened conical shell segment are identified. Defective and defect-free computer models are simulated to evaluate structural damage/defect tolerance. Safe pressurization levels are assessed for the retention of structural integrity at the presence of damage/defects. Damage initiation, growth, accumulation, and propagation to fracture are included in t

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Das, Subrata, Amitabh Wahi, and Suresh Jayaram. "Defect detection in textiles using back propagation neural classifier." Zastita materijala 64, no. 3 (2023): 308–13. http://dx.doi.org/10.5937/zasmat2303308d.

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The textile products are affected by the defects during the manufacturing processes. It is also waste of the resources used for the production and in turn it affects the business. The manual inspection in defect detections is not encouraged these days in manufacturing process. The computer vision with machine learning algorithms in automated quality control system plays an important role in detecting defects in manufacturing process as well as analyzing the quality of products. Classification of defects in knitted fabric is an active area of research around the globe. This paper presents a cla

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KANG, CHUN-WON, MASUMI HASEGAWA, and HARADHAN KOLYA. "EFFECTS OF HOLE PERFORATION AND SURFACE CUTTING ON WOOD ELASTICITY USING ULTRASONIC AND VIBRATION METHODS." Wood Research 70, no. 1 (2025): 184–94. https://doi.org/10.37763/wr.1336-4561/70.1.184194.

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This study analyzed how hole perforation and surface cutting affect ultrasonic wave propagation velocity and resonant frequency in wood. While non-destructive evaluation techniques for wood elasticity are well-established, the specific influence of defects like holes and orthogonal cuts on wave behavior remains underexplored. This study aimed to fill this gap by assessing how these defects influence wave behavior and providing new insights into their impact on wood's mechanical properties. Four softwood species and seven hardwood species were analyzed. In hardwood specimens, ultrasonic propaga

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Jones, K. M., R. J. Matson, M. M. Al-Jassim, and S. M. Vernon. "Defect generation and propagation in GaAs solar cells." Proceedings, annual meeting, Electron Microscopy Society of America 46 (1988): 926–27. http://dx.doi.org/10.1017/s0424820100106697.

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It is well known that dislocations have deleterious effects on the performance of minority carrier semiconductor devices. In a previous study(1), the results of an EBIC examination of GaAsP wide bandgap solar cells was reported. The effects of defects in the 106-108 cm-2 range on various cell parameters were investigated. However, the equally important 104-106 range was not studied. In this work, we report a study on defects in low bandgap (1.4 eV) GaAs cells in the 104-108 cm-2 range. These cells were grown by low pressure MOCVD on GaAs substrates. In order to introduce dislocations with such

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Kutsenko, Anton A. "Wave propagation through periodic lattice with defects." Computational Mechanics 54, no. 6 (2014): 1559–68. http://dx.doi.org/10.1007/s00466-014-1076-3.

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Gopalakrishnan, S. "Wave Propagation in Structures with Periodic Defects." Proceedings of the Indian National Science Academy 79, no. 4 (2013): 615. http://dx.doi.org/10.16943/ptinsa/2013/v79i4/47986.

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Haragus, Mariana, and Arnd Scheel. "Corner defects in almost planar interface propagation." Annales de l'Institut Henri Poincare (C) Non Linear Analysis 23, no. 3 (2006): 283–329. http://dx.doi.org/10.1016/j.anihpc.2005.03.003.

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Krenckel, Patricia, Yusuke Hayama, Florian Schindler, Theresa Trötschler, Stephan Riepe, and Noritaka Usami. "Propagation of Crystal Defects during Directional Solidification of Silicon via Induction of Functional Defects." Crystals 11, no. 2 (2021): 90. http://dx.doi.org/10.3390/cryst11020090.

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The introduction of directional solidified cast mono silicon promised a combination of the cheaper production via a casting process with monocrystalline material quality, but has been struggling with high concentration of structural defects. The SMART approach uses functional defects to maintain the monocrystalline structure with low dislocation densities. In this work, the feasibility of the SMART approach is shown for larger ingots. A G2 sized crystal with SMART and cast mono silicon parts has been analyzed regarding the structural defects via optical analysis, crystal orientation, and etch

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