Dissertations / Theses on the topic 'Artificial crack'
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Rehman, Atiq-Ur. "An investigation of methods of reducing fatigue crack growth by artificial crack-closure effects." Thesis, University of Salford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315379.
Full textYang, Jidong. "Road crack condition performance modeling using recurrent Markov chains and artificial neural networks." [Tampa, Fla.] : University of South Florida, 2004. http://purl.fcla.edu/fcla/etd/SFE0000567.
Full textBezerra, Agnes. "The Use of Artificial Intelligence for Assessing Damage in Concrete Affected by Alkali-Silica Reaction (ASR)." Thesis, Université d'Ottawa / University of Ottawa, 2021. http://hdl.handle.net/10393/42730.
Full text田中, 啓介, Keisuke TANAKA, 義明 秋庭, Yoshiaki AKINIWA, 博央 來海, Hirohisa KIMACHI, 和之 伊藤, and Kazuyuki ITOH. "防振ゴム材料における疲労き裂進展挙動へのJ 積分の適用." 日本機械学会, 2003. http://hdl.handle.net/2237/9154.
Full textFurfari, Domenico. "Short track growth from artificial defects in Ti-10V-2Fe-3Al : a study using optical techniques for crack measurements and detection." Thesis, Cranfield University, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.427204.
Full textHou, Chuanchuan. "Vibration-based damage identification with enhanced frequency dataset and a cracked beam element model." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/20434.
Full textIngabire, Annick, and Robin Olsson. "Standardization of Eddy Current Testing Calibration for Valve Spring Wire." Thesis, KTH, Industriell produktion, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-232712.
Full textEddy current testing (ECT) has become one of the most extensively used methods to secure theproducts and constructions when non-destructive testing is required. In typical cases of steel wiretesting, the equipment interacts with the tested material and discovers surface defects and, to alimited extent, if the inner structure is differing from the calibration sample. If the product isfound to be outside specification, it is either scrapped or reworked. This master thesis investigatesthe Eddy current testing calibration procedures performed by steel wire manufacturer SuzukiGarphyttan, which is one of the largest producers in the world of valve and transmission springwire for the automotive industry. By the research shown in this thesis, based on the investigationmade in scientific papers and by analyzing data extracted from production, a standardization ofthe calibration procedure is being presented. This is to secure both the testing reliability, andminimizing the risk of scrapping material due to inaccurate settings, for example due toinsufficient signal to noise (S/N) ratio. The focus is on probe-based, rotating testing, in this thesiscalled the circograph, since it is manually calibrated.Some of the findings established in the report: Standard Operating Procedures (SOP) based instructions is being implemented in thecompany's Quality system. This is to decrease the process variations between differentoperators and machines. Suggestions of intervals for values (Phase angle, gain, filter correction and so forth) arepresented. These values are based on collected unique production data from operators andmachines, as well as performed tests. The phase angles used are ranging between specific value intervals, and set by materialchoice in general and choice of frequency in particular. The conductivity and permeability values for oil-tempered wire, as well as penetrationdepth for three different frequencies, are presented. Hardening error cannot be detected in the circograph. Increased carbon content is decreasing conductivity and increasing resistivity, causing thephase to move slightly and decreasing the gap between noise signal and crack signal.
Nguyen, Thi Thu Trang. "Influence de l'effet de l'interface acier/béton (top-bar effect) sur la corrosion de structures en béton armé exposées en environnement de chlorures ou de carbonatation." Electronic Thesis or Diss., Université de Toulouse (2023-....), 2024. http://www.theses.fr/2024TLSEI009.
Full textReinforced concrete is known one of the most popular materials applied in construction. Nevertheless after a period of time it can be corroded. Chloride and carbonation are the main factors causing to corrosion in reinforced concrete structure. The thesis aimed to study the corrosion behavior of reinforcement concrete under carbonation or chloride environment, corresponding to the influence of top-bar effect, the cement type as well as artificial transverse crack or load-induced cracks.In general carbonation induced corrosion is usually researched from the point of view that it generates uniform corrosion. The first objective of the thesis is to confirm the opinion of macro cell or non-uniform corrosion in carbonated induced corrosion. According to the results of experiments in this part, corrosion rate in carbonated concrete reinforcement is likely to consider from the point of view of both uniform and macro cell corrosion, which is highly influenced by the ratio cathode/anode. In addition the application of CEM III using slag as addictive exhibited reduction of non-uniform corrosion effectively.The second part focuses on the influence of top-bar effect on corrosion behavior in the case carbonation induced corrosion and presence of load induced crack. Macro cell corrosion current monitoring was utilized in the experiment following the loss of mass as well as corrosion kinetic was calculated. Corrosions mainly developed at the position of the pre-cracks. Due to the top-bar effect upper bars were more corroded than bottom bars. Current corrosion value of top bars was observed higher than bottom bars. Loss of steel mass calculated from macro cell current measurement corresponds to only to a small part of the total loss of mass determined by gravimetric measurement. Uniform corrosion appears to be the main phenomena.The last part investigates the effect of top-bar effect in fibers concrete samples with or without artificial crack on chloride induced corrosion. The top steel bars are more corroded than the bottom bars and the upper part of the top bar is recorded higher corrosion than the lower part. In presence of artificial crack the top casting effect results that corrosions spread along the surface of the steel bars. Corrosion also spread along the top bar when there is no artificial crack, in a time not so different from the case of artificial crack. It confirms that top surface exposure and top bar effect are highly prejudicial for corrosion. By comparing the behavior with concrete without fibers, it appears that the addition of fibers in reinforced concrete leads to an increase of resistance to corrosion induced cracking.For each part, experimental observations are coupled with numerical simulations to compare as well as demonstrate the experimental results
Mirjana, Filipovic. "Evolution of artificial defects during shape rolling." Licentiate thesis, Högskolan Dalarna, Materialvetenskap, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:du-5215.
Full textDatsiou, Kyriaki Corinna. "Design and performance of cold bent glass." Thesis, University of Cambridge, 2017. https://www.repository.cam.ac.uk/handle/1810/269408.
Full textFilipovic, Mirjana. "Evolution of artificial defects during shape rolling." Licentiate thesis, Stockholm : Division of Mechanical Metallurgy, Department of Material Science and Engineering, Industrial Engineering and Management, Royal Institute of Technology, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4350.
Full textLipowczan, Martin. "Inverzní analýza spolehlivosti předpjatého mostu." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2018. http://www.nusl.cz/ntk/nusl-372071.
Full textSjösten, William, and Victor Vadling. "Finite Element Approximations of 2D Incompressible Navier-Stokes Equations Using Residual Viscosity." Thesis, Uppsala universitet, Institutionen för teknikvetenskaper, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-354590.
Full textRen-Zhi, Li, and 李仁志. "An Investigation of Artificial Infiltration Induced Fatigue Crack Growth Retardation." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/57975191192130123181.
Full text國立臺灣大學
機械工程學研究所
87
It is well known that fatigue fracture accounts for a great number of machanical failures. When a fatigue crack is discovered in a critical component during routine maintenance, replacement of component may not be feasible as there may not be stocks or the available down-time is too limited. Some expeditious provisory fixing may then be needed to allow the component to operate safely until more elaborate repair or replacement can be arranged. Research in fatigue has largely been concentrated on understanding the mechanisms and predicting the progress of failures. Relatively little work has been done on repairing fatigue damage. Recently, infiltration of foreign materials into a fatigue crack has previously been shown to be able to retard a crack and extend fatigue life. Systematic investigation in this topic is however still lacking. The methods employed to infiltrate foreign materials into a crack are not very reliable, giving haphazard results most of the time. The aim of the current project is to develop an efficient infiltration method to ensure thorough and reproducible results. With this method, the effect of various parameters such as infiltration load level, mechanical properties of the infiltrants and applied loading level have been investigated. In addition, a successful engineering model to predict the possible outcome of retardation repair has been proposed. This has been compared with experimental results as well as a detailed three-dimensional finite element analysis.
Chen, Yao-Rong, and 陳耀榮. "Using DEM to Analyze Crack Extension and Mechanical Behavior of Artificial Rock." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/63971134342432844198.
Full text國立臺灣大學
土木工程學研究所
99
Since World War II, the development of fracture mechanics is becoming complete. In the rock engineering field, fracture plays an important role on rock strength, so crack propagation is a big issue for studying fracture behavior of material. When the rock material damage is caused not by material strength but stress concentration of the pre-exist cracks, it becomes different from intact rock on failure strength and failure behavior, so rock mechanics can not help us do the analysis, design on engineering. On the side of geology, due to the strong orogeny, the rock mass in Taiwan is plenty of discontinuities. The discontinuities, which are perceived as the pre-existing cracks in rock mass, can affect the strength of the rock mass. In view of this, it is benefit to know the pattern of fracture propagation behaviors of artificial rocks with pre-existing cracks under biaxial loading for earthquake disaster prevention. This study was based on numerical analysis of data collected from laboratory test. The numerical simulation is executed by the distinct element method (DEM) based software, Particle Flow Code 2D. In order to acquire the parameters for PFC2D simulating and verification the PFC2D results, this study refers to data of artificial rocks are made to apply the uni-axial compression test, the Brazilian disk test and the Central through Cracked Brazilian Disc test(Huang, 2010). According to the simulation results, the lateral stress caused a great influence on fracture propagation behaviors. Behavior of specimen with single pre-exist crack is different between high and low confining pressure. The fracture propagation behavior was not obvious under higher lateral stress level. The broken area was concentrated near the pre-exist cracks and formed broad fracture lines.
Chuang, Chung-ju, and 莊忠儒. "Application ultrasonic A-Scan and Phased-array technology to measure reliability of the natural and artificial crack of material." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/63318147720195652539.
Full text國立雲林科技大學
環境與安全工程系碩士班
93
The crack has the most influence on strength of structure, therefore it need to understand the crack position and size accurately, and then prevent the great accident from happening, at last this study will research on the crack testing methods of the industry. According to ultrasonic wave has extremely good measuring ability to the metal material crack and defect of welding. And the ultrasonic wave utilized to measure metal material weld and tired caused flaw, for example crack, integration partial, seam, etc. But most judgments of the detection methods between good and bad are by the artificial crack, so this study measures the depth distance of the natural crack from surface, the irregularity of cross-section is the most different from using the artificial crack, asymmetric reflect surface has certain difficulty while transmitting, but measuring the natural crack has higher credibility than measuring the artificial crack. This study will use four methods including ultrasonic A-Scan, RT, TOFD, Ultrasonic Phased-Array to measure the same natural crack and compare with the dependability and restriction of each method, then offer user an effective, accurate and faster examining method.
Wei-MingTseng and 曾韋鳴. "A Study of Crack Identification of A Beam and Plate by Artificial Neural Network Method and Discrete Wavelet Transform." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/88106574207567822052.
Full text國立成功大學
系統及船舶機電工程學系碩博士班
98
Neural networks have been widely used in various fields, such as diagnosis and monitoring of industrial engineering system, digital image processing and analysis, speech recognition, sonar and seismic signal classification, and financial management. The method can process complex information and establish the mapping relationship between input and output by learning and revision. Finally, an identification system is acquired. The aim of this study is to find the depth of the damage of an aluminum bar and to detect the approximate length of the crack of a damaged plate by the discrete wavelet transform and the neural network method. In numerical analysis, the first mode shape of a damaged cantilever beam and plates are simulated by the finite element method. The obtained mode shapes of the damaged cantilever beam and plates are then transformed by the discrete wavelet transform. The damage index of the beam or plates can be obtained by reconstructed the high frequencies detail signals of each layer and used to be the neural networks training samples, and then the damage identification system for beams and plates can finally be established. In experiment analysis, several accelerometers are used to measure the vibration responses of the beam, and the first mode shapes of the beam is attained by using the wavelet packet node norm. Finally, the experimental damage index are obtained and used as inputs of the identification system to find the approximate depth of the damage of a cantilever beam. It is believed that the proposed crack identification system is feasible to identify the damage depths of cantilever beams.
Hsieh, Cheng-Ying, and 謝承穎. "Integration of image processing, computer vision, and artificial intelligence to identify concrete surface cracks." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/f53e74.
Full text國立臺灣大學
土木工程學研究所
107
Structural health monitoring becomes more and more important in practice because this technology can elongate the structural life cycle as well as protect structures against natural hazards. Moreover, structural health monitoring systems can automatically inform residents and users for the current condition of structures and engineers for the current performance. In past, structural health monitoring relies on the contact sensors to acquire structural responses and then diagnoses structures in accordance with the measurements. In this research, a new method is developed to detect and quantify the concrete cracks based on the noncontact image measurements. This method integrates computer vision and deep learning to identify the crack existence and geometry. The identified cracks can provide indirect information for experts to further investigate the structural conditions. This study exploits deep learning and transfer learning, e.g., the tools in the category of artificial intelligence, to train and establish a concrete segmentation model that can identify the locations of cracks in images. In this model, the crack features can be obtained from the convolutional neural network and then automatically identify whether the cracks are present and where the cracks are. Then, the image processing and computer vision are implemented to highlight and extract these cracks from images. Finally, the geometry of these cracks (i.e., lengths and widths) can be calculated by image measurement techniques. To verify the proposed method, this study employs the images of concrete surface cracks obtained from the real-world structures and then evaluate the reliability of this method. In the verification, the pre-calibrated stereo camera model with a two-camera setup is used to verify the actual lengths and widths of cracks. The calculated results are compared with the actual measurements. As a result, the proposed method can successfully determine crack geometry. Moreover, the method also benefits users to obtain crack information and to turn into performance evaluation of concrete structures for structural health monitoring.
Yi-HaoYen and 顏奕豪. "Damage Detection of a Plate with Multiple Cracks by two-Dimensional Discrete Wavelet Transforms and Artificial Neural Network." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/31882378961747647614.
Full text國立成功大學
系統及船舶機電工程學系碩博士班
101
Structural damage has been a very important issue in engineering. If damage can be detected in a timely manner, many disasters can be prevented. In recent years, wavelet transform methods have been widely used in various domains, such as image compression, noise removal, edge detection, communication, etc.This study will use the two-dimensional discrete wavelet transform method to detect the position of cracks in plate. Running data through the artificial neural network allows for large computations to be calculated at rapid speeds, and relationships between input and output are quickly achieved. The network will continuously learn and make corrections. The artificial neural network along with the two-dimensional discrete wavelet transform method is used to identify the degree of damage in this study. During the analytical simulation, several plates with cracks are analyzed and damage indexes are assigned to represent the length and the distance between the two cracks. After which, we narrowed our selection area to a single crack on the board to obtain new damage indexes. These new damage indexes, which is the training sample is then inputted into the artificial neural network. We are then able to take the damage indexes from other plate samples to be analyzed with-in the artificial neural network to obtain the length of the crack. As a result we were able to devise a method for analyzing cracks on a plate efficiently and systematically. Lastly, in order to narrow the gap between the simulations and the actual experiments, we eliminated the mode shapes’ difference between simulations and experiments, with the intention to obtain more precise results from the artificial neural network.
Zhi-ShiangLu and 盧智祥. "Damage Detection in Stiffened Plates with Multiple Cracks by Artificial Neural Network Method and Two-Dimensional Discrete Wavelet Transform." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/50420876316219653586.
Full text國立成功大學
系統及船舶機電工程學系碩博士班
99
During recent decades, there has been an increase in the number of researchers who have devoted themselves to artificial neural networks. This method has many useful characteristics that appeal to such researchers, including adaptation learning capability, fault-tolerant capability, and the ability to use practice examples to build a neural networks system. The method can process complex information and establish the correspondence between input and output relationships by learning and revision. Therefore, the neural networks have been widely used in various fields, such as analysis and design of industrial engineering system, diagnosis of mechatronics engineering system, digital image processing and analysis, quality of products analysis, and commercial financial management. In this study, two-dimensional discrete wavelet transforms and artificial neural network are utilized to identify single cracks or multi-cracks in stiffened plates. In numerical analysis, based on the dynamic properties of a stiffened plate before and after the damage has been dealt, the mode shapes for the stiffened plates are computed by FEM. The two-dimensional discrete wavelet transforms are applied to analyze the mode shapes of the stiffened plates, and then the obtained training samples of neural networks are used to establish the damage identification system for identifying the damage degree of a crack in stiffened plates. In the experiment analysis, several accelerometers are used to measure the vibration responses of the stiffened plate, and the first mode shapes of the stiffened plate are attained by using the wavelet packet analysis. The experimental damage indices are obtained by two-dimensional discrete wavelet transforms and artificial neural network. Finally, the results of the experiments are compared to the damage identification system used to detect the damage degree of the crack in the stiffened plates.
Biolatto, Guillermo Adriel, Héctor Jorge Ezequiel Fraire, and Mariano Nicolás Novella. "El manejo reproductivo posparto en tambos de la zona de James Craik." Bachelor's thesis, 2014. http://hdl.handle.net/11086/4693.
Full textEl siguiente trabajo se centrará en la evaluación del manejo reproductivo postparto de la vaca lechera. El trabajo se hará sobre 4 tambos de la zona de James Craik que forman parte de un grupo: Tambo Biolatto, Tambo Pedernera, Tambo Peréz y Tambo Pineda. El objetivo del trabajo es conocer los distintos manejos reproductivos que lleva adelante cada tambo, comparar los resultados que se obtienen a través de estos distintos manejos, buscar las causas de los problemas reproductivos hallados y a partir de estos formular una serie de propuestas de solución.
Naddaf, Hamid Eskandari. "Fracture Characteristics Of Self Consolidating Concrete." Thesis, 2008. https://etd.iisc.ac.in/handle/2005/761.
Full textNaddaf, Hamid Eskandari. "Fracture Characteristics Of Self Consolidating Concrete." Thesis, 2008. http://hdl.handle.net/2005/761.
Full text