10,037 results
Search Results
152. A study of the relaxation phenomena in the fabrics containing elastane yarns
- Author
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Geršak, Jelka, Šajn, Dunja, and Bukošek, Vili
- Published
- 2005
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153. Pappersfiber karakterisering och kvantifiering
- Author
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Sveinsson, Ívar
- Subjects
x-ray tomography ,Applied Mechanics ,Teknisk mekanik ,deformation ,characterization ,Paper fibre ,fiber - Abstract
With the advent of X-ray computerised tomography (CT), the possibility of capturing precise volumetric 3D images has become an invaluable tool within the material sciences. With tomographs and synchrotrons becoming more readily available to researchers and scanning time decreasing with newer equipment, the amount of data to be analysed is steadily rising. This rapid increase in data acquisition motivates the development of automatic methods to transform CT images from qualitative to quantitative data. In this work, a method to automatically characterise paper fibres from CT images based on their centre-line and mapping their deformation is presented. Methods for fibre characterisation are presented and tested on computer-generated fibres and CT images of paper fibres. Med tillkomsten av datorbaserd röntgentomografi (CT) har möjligheten att fånga exakta volymetriska 3D-bilder blivit ett ovärderligt verktyg inom materialvetenskapen. Den mängd data som ska analyseras växer hela tiden tack vare ökad tillgänglighet till tomografer och synkrotroner och minskad skanningstid i och med den tekniska utvecklingen av utrustningen som används. Denna snabba ökning av datainsamling motiverar utvecklingen av automatiska metoder för att omvandla CT-bilder från kvalitativa till kvantitativa data. I detta arbete presenteras en metod för att automatiskt karakterisera pappersfibrer från CT-bilder baserad på deras mittlinje och kartlägga deras deformation. Metoder för fiberkarakterisering presenteras och testas på datorgenererade fibrer och CT-bilder av pappersfibrer.
- Published
- 2021
154. The Influence of Tian Gan Deflection on the Flatness of Hanging Scrolls in Chinese Painting and Calligraphy.
- Author
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Zhou, Yujun and Gong, Decai
- Subjects
CHINESE painting ,CALLIGRAPHY ,DIGITAL image correlation ,BENDING moment ,HUMIDITY - Abstract
The forms of traditional Chinese painting and calligraphy are varied, including hanging scrolls, horizontal scrolls, screens, hand scrolls, and albums. Hanging scrolls are hung on the wall for display, but curling edges often appear on both sides of the hanging scroll. Various factors influence the deformation of paintings and calligraphy, such as temperature and relative humidity and the susceptibility of materials in scrolls as well as mounting techniques. The influences of structural components, such as tian gan (hanging rod), hanging rope, and di gan (lower rod) have received little attention. This paper focuses on the influences of tian gan deflection on the deformation of hanging scrolls, with the help of DIC (digital image correlation) visualization. Deflections of tian gan in two types of hanging methods were compared with a theoretical study. It was suggested that the influence of axial force was of great importance on the increase in deflection and bending moment. To reduce the bending of tian gan as much as possible, the vertical hanging method with appropriate position for the hanging rope should be chosen for mounting hanging scrolls. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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155. Utilizing design sensitivity analysis for 3D optimization of transformer tank shields considering eddy currents
- Author
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Yao, Yingying, Seop Koh, Chang, Seop Ryu, Jae, Xie, Dexin, and Gun Um, Tae
- Published
- 2004
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156. Monitoring and early warning systems – a design for human survival
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Skyttner, Lars
- Published
- 2002
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157. ANALYSIS OF THE CONDITION OF A PIPE FIXED IN A CLAMPING DEVICE
- Author
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Mahammadali Nuriyev and Emin Musa Afandiyev
- Subjects
clamp ,business.product_category ,Materials science ,lcsh:Mechanical engineering and machinery ,education ,0211 other engineering and technologies ,General Physics and Astronomy ,02 engineering and technology ,cartridge ,Stress (mechanics) ,stress ,Reliability (semiconductor) ,0203 mechanical engineering ,021105 building & construction ,Ultimate tensile strength ,lcsh:TJ1-1570 ,Drill ,business.industry ,paper gauge ,General Engineering ,deformation ,Structural engineering ,load ,holding capacity ,Wedge (mechanical device) ,Clamping ,lcsh:QC1-999 ,pipe ,020303 mechanical engineering & transports ,Deformation (engineering) ,business ,Casing ,lcsh:Physics - Abstract
Due to the fact that clamping devices are widely used in various industries, the requirements for the operation of such devices are constantly increasing. This is due to an increase in the general requirements for processing accuracy, as well as an increase in the forces acting on the clamped part. The reliability of these devices when working with thin-walled cylindrical parts is of great importance. Thin-walled cylinders used in mechanical engineering are subject to significant loads. With prolonged exposure to loads from clamping forces, as well as from axial tensile forces, plastic deformations of cylindrical parts occur. In the oil and gas industry, when clamping drill and casing pipes in some areas in the capture zone, stresses exceed the yield strength. Multiple clamping of the pipe will reduce the pipe wall in the gripping area, which causes premature pipe failure. Therefore, increasing the holding capacity of clamping mechanisms is relevant. Analysis of broken drill pipes, which have been operating in wedge grips for a long time, showed that in most cases the pipes undergo plastic deformation caused by damage to the pipe surface by the teeth of the ram. To clarify the actual conditions of loading the pipe and the possibilities of increasing the capacity of the clamping devices, studies of the contact pressures in the clamping zone were carried out. A new pipe clamping chuck is also presented, which provides a sufficiently high reliability of fastening of cylindrical parts.
- Published
- 2021
158. Modeling Object Motion on Arbitrary Unstructured Grids Using an Invariant Principle of Computational Domain Topology: Key Features.
- Author
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Sarazov, Aleksey, Kozelkov, Andrey, Strelets, Dmitriy, and Zhuchkov, Roman
- Subjects
VISCOUS flow ,NAVIER-Stokes equations ,FLUID flow ,TOPOLOGY ,GEOMETRIC analysis ,COMPRESSIBLE flow ,MOTION - Abstract
This paper uses a finite volume algorithm to address the numerical modeling of fluid flow around moving bodies. The Navier–Stokes equations, which describe the flow of viscous compressible gas, along with key boundary conditions and discretization schemes, are presented. As the motion of boundaries typically leads to changes in the control volumes, the basic discretization schemes need to be adapted. This paper provides a detailed discussion on the adaptation of the initial system to deforming boundaries while preserving communication topology. The method for calculating the boundary velocity is a crucial element of the numerical scheme. The paper proposes an approach to reconstruct the boundary velocity vector using deformation analysis and the condition of geometric conservation. This approach ensures correct simulation results for arbitrary unstructured computational grids. A comparison of two approaches to reconstructing the boundary velocity vector for characteristic aviation problems in the direct formulation is presented. It is shown that the proposed approach allows for more accurate modeling of object motion on arbitrary grids using the "invariant" principle of the computational domain topology. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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159. An efficient algorithm to estimate optimal preform die shape parameters in forging
- Author
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Castro, Catarina F., Costa Sousa, Luísa, António, C.A.C., and César de Sá, J.M.A.
- Published
- 2001
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160. Bending and twisting of cylindrical solder interconnections with creep
- Author
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Lau, John H.
- Published
- 2001
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161. Study of the relationship between deformation of the thread and built‐in fibres
- Author
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Rudolf, Andreja and Geršak, Jelka
- Published
- 2001
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162. Viscoplastic Anand model for solder alloys and its application
- Author
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Cheng, Z.N., Wang, G.Z., Chen, L., Wilde, J., and Becker, K.
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- 2000
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163. Reaction heat effects on initial linear shrinkage and deformation in stereolithography
- Author
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Narahara, Hiroyuki, Tanaka, Fumiki, Kishinami, Takeshi, Igarashi, Satoru, and Saito, Katsumasa
- Published
- 1999
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164. Comparative investigation into the dynamic explicit and the static implicit method for springback of sheet metal stamping
- Author
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Lee, S.W., Yoon, J.W., and Yang, D.Y.
- Published
- 1999
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165. On the integration of stresses in large deformations plasticity
- Author
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Marcon, A.F., Bittencourt, E., and Creus, G.J.
- Published
- 1999
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166. Effect of paper structure on the load elongation behaviour of fibre-to-fibre bonds
- Subjects
bonds ,bond strength ,in-situ deformation ,deformation ,fibers - Abstract
The deformation of paper and its fibre bonds was studied by straining thin paper structures inside the specimen chamber of a scanning electron microscope. The average bond strength values of different sheet structures were characterized by several methods. The handsheet structures were varied by refining and by addition of bond strength chemicals. The preliminary results obtained show that the structure of the sheet has a pronounced effect on the elongation properties of paper and of its fibres. The coarseness of the fibres had a distinct effect on the loading capacity of fibres and on the simultaneous straining behaviour. The thin wall springwood fibres often became inactive only after the final rupture of the structure. The summerwood fibres tended to become inactive earlier through breakage of the fibre bonds. A blinking light phenomenon was observed during the SEM straining of some paper specimens. The light blinks were interpreted as complete breakages of fibre-to-fibre bonds. The structural features of the studied handsheets had different effects on the bond strength values obtained by the various methods. These results seemed to indicate that refining produced a sheet structure which could be loaded in a more homogeneous manner. This was also reflected as higher values of bond strength. All bond strength methods used showed that starch increases the bond strength and that the debonding chemical decreases it.
- Published
- 1985
167. Мнения и факты в теоретических основах технологий искусственных волокон и целлюлозно-бумажного производства
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Engineering ,структурообразование ,business.industry ,paper ,Pulp (paper) ,deformation ,Paper production ,thermofixation ,fibers ,engineering.material ,Pulp and paper industry ,деформация ,бумага ,гидрофобные взаимодействия ,sulphate cellulose ,волокна ,сульфатная целлюлоза ,structure formation ,hydrophobic interaction ,фазовые взаимодействия ,phase interactions ,activation ,активация ,business ,термофиксация - Abstract
В статье рассмотрены различные подходы к пониманию природы связей в целлюлозно-волокнистых системах. Анализ результатов многочисленных исследований показывает, что при изготовлении высокотехнологичных целлюлозно-бумажных изделий необходимо учитывать специфику процессов структурообразования в дисперсных системах, дисперсионной средой в которых является вода или её растворы, на каждом этапе в многоступенчатых системах химической переработки растительного сырья. В статье освещаются особенности диалектики развития прикладной науки (отрицание отрицания) и её влияние на решение проблем отечественной научной школы текстильной и целлюлозно-бумажной промышленности. Выделение физикохимии растворов высокомолекулярных соединений из коллоидной химии в отдельную науку явилось причиной создания теоретических основ технологии искусственных волокон и целлюлозно-бумажного производства. Игнорирование научных положений о структурообразовании дисперсных систем с точки зрения фазового взаимодействия их компонентов и релаксационного состояния является причиной сдерживания прогресса в совершенствовании технологических процессов целлюлозно-бумажного производства. Разработанные теоретические основы получения дисперсных структур с заданными механическими свойствами не были доведены до создания моделей технологических процессов, необходимых для изготовления отечественного технологического оборудования. Таким образом, исключение представлений коллоидной химии и её раздела – физико-химической механики из повседневной практики целлюлозно- бумажного производства препятствуют целенаправленному решению проблем при получении высокотехнологичных материалов., The article deals with different approaches to understanding the nature of bonds in cellulose-fibrous systems. Analysis of the results of numerous studies shows that in the manufacture of high-tech pulp and paper products it is necessary to take into account the specifics of the processes of structure formation in dispersed systems, the dispersion medium in which is water or its solutions, at each stage in multi-stage systems of chemical processing of vegetable raw materials. The article highlights the features of dialectics of applied science (denial of negation) and its impact on solving the problems of the domestic scientific school of textile and pulp and paper industry. The separation of physical chemistry of solutions of high-molecular compounds from colloidal chemistry into a separate science was the reason for the creation of the theoretical foundations of the technology of artificial fibers and pulp and paper production. Ignoring the scientific provisions on the structure formation of dispersed systems from the point of view of the phase interaction of their components and the relaxation state is the reason for holding back progress in improving the technological processes of pulp and paper production. The developed theoretical basis for obtaining dispersed structures with specified mechanical properties were not brought to the creation of models of technological processes necessary for the manufacture of domestic technological equipment. Thus, the exclusion of colloidal chemistry, and its section – physical and chemical mechanics, from the daily practice of pulp and paper production prevents the purposeful solution of problems in the production of high-tech materials., №225 (2018)
- Published
- 2018
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168. Cohomology and Crossed Modules of Modified Rota–Baxter Pre-Lie Algebras.
- Author
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Zhu, Fuyang and Teng, Wen
- Subjects
ALGEBRA - Abstract
The goal of the present paper is to provide a cohomology theory and crossed modules of modified Rota–Baxter pre-Lie algebras. We introduce the notion of a modified Rota–Baxter pre-Lie algebra and its bimodule. We define a cohomology of modified Rota–Baxter pre-Lie algebras with coefficients in a suitable bimodule. Furthermore, we study the infinitesimal deformations and abelian extensions of modified Rota–Baxter pre-Lie algebras and relate them with the second cohomology groups. Finally, we investigate skeletal and strict modified Rota–Baxter pre-Lie 2-algebras. We show that skeletal modified Rota–Baxter pre-Lie 2-algebras can be classified into the third cohomology group, and strict modified Rota–Baxter pre-Lie 2-algebras are equivalent to the crossed modules of modified Rota–Baxter pre-Lie algebras. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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169. An Optimized Approach to Multistage Permanent Deformation Testing of Granular Materials.
- Author
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Pérez-González, Erdrick and Bilodeau, Jean-Pascal
- Subjects
MATERIALS testing ,STRAIN rate ,GRANULAR materials ,CYCLIC loads ,DEFORMATIONS (Mechanics) - Abstract
Accurately characterizing permanent deformation in granular materials subjected to cyclic loading is crucial for pavement design. This paper introduces an alternative approach to characterizing permanent deformation in a framework that reduces the number of load cycle repetitions by applying an alternative analytical strategy based on plastic strain rate variation over time. The methodology uses a cycle-hardening approach to establish correlations between short-term (post-compaction) and long-term (shakedown state) plastic strain accumulation. This alternative approach provides an efficient means to accelerate the characterization of permanent deformation, ensuring the integrity and validity of the assessment in a more time-efficient and resource-optimized way. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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170. Investigation of the Deformation Behavior of Baffle Structures Impacted by Debris Flow Based on Physical Modelling.
- Author
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Chen, Weizhi, Zhang, Bei, Xu, Na, and Huang, Yu
- Subjects
DEBRIS avalanches ,EVIDENCE gaps ,HAZARD mitigation ,IMPACT loads ,ENERGY dissipation - Abstract
The utilization of baffle structures as a highly effective strategy for mitigating debris flow has attracted significant scholarly attention in recent years. Although the predominant focus of existing research has been on augmenting the energy dissipation capabilities of baffle structures, their deformation behavior under impact load has not been extensively investigated. Addressing this research gap, the current study systematically designs a series of physical model experiments, incorporating variables such as baffle height, shape, and various combinations of baffle types to comprehensively analyze the deformation characteristics of baffles subjected to debris flow impact. The experimental results reveal that the deformation of baffle group structures demonstrates a marked non-uniform spatial distribution and exhibits a latency effect. Additionally, distinct baffle configurations show considerable variations in peak strain, suggesting that combining different baffle shapes can not only optimize energy dissipation but also enhance resistance to deformation. Moreover, the relationship between baffle height and the development of deformation in relation to energy dissipation capacity is inconsistent, indicating that deformation must be a key consideration in the design of baffle structures. Consequently, this paper advocates for the formulation of a deformation-based design strategy for baffle structures, with the findings presented herein providing a foundational reference for future studies. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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171. Analysis of the Dihedral Corner Reflector's RCS Features in Multi-Resource SAR.
- Author
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Liu, Jie, Li, Tao, Ma, Sijie, Wen, Yangmao, Xu, Yanhao, and Nie, Guigen
- Subjects
LANDSLIDES ,ENERGY dissipation ,TIME series analysis - Abstract
Artificial corner reflectors are widely used in the vegetated landslide for time series InSAR monitoring due to their permanent scattering features. This paper investigated the RCS features of a novel dihedral CR under multi-resource SAR datasets. An RCS reduction model for the novel dihedral corner reflector has been proposed to evaluate the energy loss caused by the deviation between the SAR incident angle and the CR's axis. On the Huangtupo slope, Badong county, Hubei province, tens of dihedral CRs had been installed and the TSX–spotlight and Sentinel-TOPS data had been collected. Based on the observation results of CRs with more than ten deviation angles, the proposed reduction model was tested with preferable consistency under a real dataset, while 2 dBsm of systematic bias was verified in those datasets. The maximum incident angle deviation in the Sentinel data overlapping area is over 12°, which leads to a 2.4 dBsm RCS decrease for horizontally placed dihedral CRs estimated by the proposed model, which has also been testified by the observed results. The testing results from the Sentinel data show that in high, vegetation-covered mountain areas like the Huangtupo slope, the dihedral CRs with a 0.4 m slide length can be achieve 1 mm precision accuracy, while a side length of 0.2 m can achieve the same accuracy under TSX–spotlight data. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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172. Impact of Opencast Coal Mining on Surface Topography in Salanpur Block, District Paschim Bardhaman, West Bengal.
- Author
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Mahata, Sangita and Sharma, Vishwambhar Nath
- Subjects
SURFACE topography ,DEFORMATION of surfaces ,NATURAL resources ,REMOTE sensing ,SURFACE area - Abstract
The study is aimed at understanding the extent of topographic deformation due to opencast coal mining projects in Salanpur Blocks, District Paschim Bardhaman, West Bengal, and suggests mitigation measures. Five major opencast mining projects namely Bonjemehari, Dabor, Sangramgarh, Mohanpur, and Dalmiya are covered in the case study. These coal mines featured large opencast quarries and associated spoil dump ridges. These coal mines have defaced the surface topography as the surface area covered by positive topography (spoil dump ridges) is less than the negative topography (opencast quarries). This paper shows that the deformation of surface topography is by far the most significant impact of mining among the various geo-environmental impacts. Land is our most important natural resource that needs to be tended carefully and requires proper conservation measures. In this study, various sources of secondary data and Primary data have been used to find out the extent of topographic deformation. The authors have used Remote sensing/Geographic Information System techniques for analyzing and interpreting Satellite data. The study suggests suitable mining dumping sites depending on multi-criteria analysis for disposal of mining spoil rather than dumping the material elsewhere. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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173. Abelian Extensions of Modified λ -Differential Left-Symmetric Algebras and Crossed Modules.
- Author
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Zhu, Fuyang, You, Taijie, and Teng, Wen
- Subjects
MODULES (Algebra) ,COHOMOLOGY theory ,ALGEBRA - Abstract
In this paper, we define a cohomology theory of a modified λ -differential left-symmetric algebra. Moreover, we introduce the notion of modified λ -differential left-symmetric 2-algebras, which is the categorization of a modified λ -differential left-symmetric algebra. As applications of cohomology, we classify linear deformations and abelian extensions of modified λ -differential left-symmetric algebras using the second cohomology group and classify skeletal modified λ -differential left-symmetric 2-algebra using the third cohomology group. Finally, we show that strict modified λ -differential left-symmetric 2-algebras are equivalent to crossed modules of modified λ -differential left-symmetric algebras. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
174. A Multisubstructure-Based Method for the Assessment of Displacement and Stress in a Fluid–Structure Interaction Framework.
- Author
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Xie, Changchuan, Huang, Kunhui, Meng, Yang, Gao, Nongyue, and Zhang, Zhitao
- Subjects
FLUID-structure interaction ,VORTEX lattice method ,DISPLACEMENT (Psychology) ,STRAINS & stresses (Mechanics) ,STRESS concentration - Abstract
A multisubstructure-based method for assessing the deformation and stress of a fine-meshed model according to a coarse model was proposed. Integrating boundary conditions in a local fine-meshed model, a displacement mapping matrix from the coarse model to the fine-meshed model was constructed. The method was verified by a three-level panel in a fluid–structure interaction (FSI) framework by integrating the steady vortex lattice method (VLM). A comparison between the inner deformation distribution of the coarse model and that of the global fine-meshed model obtained from MSC.Nastran was carried out, and the results showed that the coarse model failed to demonstrate reliable strains and stresses. In contrast, the proposed method in this paper can effectively depict the inner deformation and critical stress distribution. The deformation error was lower than 8%, meeting engineering requirements. Moreover, the results of different working conditions can achieve a similar relative error of displacement for an identical position. The easy storage of the displacement mapping matrix and the convenience of the boundary information transformation among all substructure levels are prominent aspects. As a result, there is a solid foundation for addressing the time-dependent problem in spite of the simultaneity and region. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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175. Parametric Study of the Deep Excavation Performance of Underground Pumping Station Based on Numerical Method.
- Author
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Zhang, Jiani, Yang, Zhenkun, and Azzam, Rafig
- Subjects
PUMPING stations ,EXCAVATION ,ELASTIC foundations - Abstract
Environmental responses to deep excavations are combined results of numerous factors. The effects of some factors are relatively straightforward and can be considered carefully during the design. On the other hand, more features impact excavation-induced performances indirectly, making their influences difficult to be clearly understood. Unfortunately, the complexity and non-repeatability of practical projects make it impossible to thoroughly understand these issues through realistic deep excavation projects. Therefore, parametric studies based on repeatable laboratory and numerical tests are desired to investigate these issues further. This work examines the influence of several key features on excavation-induced displacements through a series of 3D numerical tests. The study includes the choice of soil constitutive models, the modeling method of the soil–wall interface, and the influences of various key soil parameters. The comparison shows that the MCC model can yield a displacement field similar to the HSS model, while its soil movement is greatly improved compared to the MC model. Both the soil–wall interface properties and soil parameters impact the excavation-induced displacement to a large extent. In addition, the influence mechanisms of these parameters are analyzed, and practical suggestions are given. The findings of this paper are expected to provide practical references to the design and construction of future deep excavation projects. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
176. Numerical Investigation of Earth Berm Effects on Prefabricated Recyclable Supporting Structure in Circular Excavations.
- Author
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Chen, Lichao, Guo, Chengchao, and Cao, Dingfeng
- Subjects
STRAINS & stresses (Mechanics) ,BENDING moment ,EXCAVATION ,SAFETY factor in engineering - Abstract
The prefabricated recyclable supporting structure (PRSS) is an innovative support system that integrates a steel skeleton with polymer waterproof technology. Earth berms are extensively adopted to support the PRSS, but there is limited understanding on the factors influencing their behavior in circular excavations. In this paper, a numerical model is first validated with a case history in Henan, China. Afterwards, the geometric parameters of the earth berms, including the height (H), the top width (B
1 ), and the bottom width (B2 ), on the behavior of the PRSS, are investigated. It is shown that, by increasing the height, top width and bottom width of earth berms, the lateral deflections, and bending moments of supporting piles, as well as the ground surface settlements, tend to decrease. However, the reduction effect of these parameters diminishes as well. Moreover, the raised effective formation level considering the effect of the earth berms on stability and deformation analyses is discussed. The factor of the safety of the excavation is almost doubled when axisymmetric conditions are considered compared to plane strain conditions. In deformation analysis, the raised effective formation level increases with the height of the earth berms until a steady value is reached. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
177. Estimation of active surface deformation using PSInSAR technique of the Central Himalayan region.
- Author
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Kothyari, Girish Ch., Dumka, Rakesh K., Luirei, Khayingshing, Kandregula, Raj Sunil, Taloor, Ajay Kumar, Malik, Kapil, Joshi, Achla, Patidar, Atul K., and Bhan, Uday
- Subjects
DEFORMATION of surfaces ,SYNTHETIC aperture radar ,GEODETIC observations - Abstract
The Kumaun Himalaya is considered as the most active part of the Central Seismic gap in the Indian Sub-continent. In this paper, we presented active surface deformation rates of the Kumaun region from February 2017 to February 2021 using the Persistent Scatterer Interferometric Synthetic Aperture Radar (PSI) technique. The cumulative displacement that occurred during the span of 4 years is ±55 mm, whereas the Line of Sight (LOS) deformation velocity rate ranges is ±7 mm/yr. Apart from PSI, we also estimated the b-value of the Kumaun region from 1803 to 2021 (399 events) and its value is 0.54 ± 0.03. A distinct NE-SW trend of b-value is observed where earthquakes with M>6 occurred towards NE of this trend. The PSIderived deformation reveals that the central part of the Inner Lesser Himalaya along with the Main Central Thrust (MCT) zone is dominated by uplift. The zone between the Munsiari Thrust (MT) and MCT in the central region shows the maximum uplift ranging 5-7 mm/yr which exactly lies above the mid-crustal ramp of the Main Himalayan Thrust (MHT). Our results are well corroborated with available observations of geodetic strain and peak ground acceleration values. However, the deformation patterns and highvelocity rates in the central part of the study area between MT and MCT indicate the accumulation of high stress. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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178. 大截面矩形顶管施工对既有管线影响研究.
- Author
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丰土根, 周坤, 张箭, 陈子昂, and 彭朋
- Abstract
Copyright of Engineering Mechanics / Gongcheng Lixue is the property of Engineering Mechanics Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2024
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179. Crackling Wires
- Author
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Sethna, James P.
- Published
- 2007
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180. Thermal deformation analysis of BGA package by digital image correlation technique
- Author
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Zhang, J., Li, M., Xiong, C.Y., Fang, J., and Yi, S.
- Published
- 2005
- Full Text
- View/download PDF
181. Mechanical characterization of Sn‐3.5Ag solder joints at various temperatures
- Author
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Rhee, H., Subramanian, K.N., Lee, A., and Lee, J.G.
- Published
- 2003
- Full Text
- View/download PDF
182. The evaluation of fused knitted systems stability
- Author
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Strazdiene, Eugenija and Gutauskas, Matas
- Published
- 2003
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183. Finite Element Simulation of Bending Thin-Walled Parts and Optimization of Cutting Parameters.
- Author
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Hailong, Ma, Aijun, Tang, Shubo, Xu, and Tong, Li
- Subjects
ELASTIC deformation ,TITANIUM alloys ,FINITE element method ,DENTAL metallurgy - Abstract
Aiming at the problems of large elastic deformation and low machining accuracy in cutting titanium alloy thin-walled parts, this paper establishes the finite element model of milling titanium alloy thin-walled parts, and simulates and analyses the milling process of titanium alloy thin-walled parts by the statics analysis module of ANSYS 15.0 software. The maximum deformation point of the workpiece in the milling process is determined. Then the combination of cutting parameters that can minimize the deformation is determined by the orthogonal experiments of four factors and four levels. This paper designs the single factor experiments, which study the distribution of the milling force and the deformation law of the parts in the milling process. Moreover, this paper carries out the optimal design of the cutting parameters by orthogonal experiments, which provides a reference for the selection of the cutting parameters for the bending thin-walled parts of titanium alloy. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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- View/download PDF
184. ANALYSIS BY THE FINITE ELEMENT METHOD OF THE TENSIONS AND DEFORMATIONS PRODUCED IN THE MECHANIZED SUPPORT BEAMS.
- Author
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ȘOICA, ALEXANDRA, URDEA, GHEORGHE BOGDAN, and FLOREA, VLAD ALEXANDRU
- Subjects
DEFORMATIONS (Mechanics) ,FINITE element method ,DIFFERENTIAL equations ,GIRDERS ,MATHEMATICAL models ,COMPUTER-aided design - Abstract
This paper presents the analysis by the finite element method of the tensions and deformations produced in the mechanized support beams. The finite element method allows the analysis of physical phenomena that can be described with the help of mathematical models made up of systems of differential equations with initial and boundary conditions. From the results obtained in this paper, it was observed that the asymmetries with the greatest influence are those with respect to the vertical-longitudinal plane of the mechanized support [ABSTRACT FROM AUTHOR]
- Published
- 2023
185. Deformation of High Rise Cooling Tower through Projection of Coordinates Resulted from Terrestrial Laser Scanner Observations onto a Vertical Plane.
- Author
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Beshr, Ashraf A. A., Basha, Ali M., El-Madany, Samir A., and El-Azeem, Fathi Abd
- Subjects
COOLING towers ,DEFORMATIONS (Mechanics) ,TALL buildings ,CONSTRUCTION materials ,OPTICAL scanners - Abstract
The appearance and development of new construction materials, technology and accurate geodetic instruments have led to the necessity of their inevitable use in the health monitoring, maintenance, and restoration of civil structures and special structures such as high-rise cooling towers. This paper presents an accurate practical and analytical method for determining the structural deformation and axis inclination of high rise cooling towers using terrestrial laser scanner (TLS) observations through the projection of tower surface points coordinates on a vertical plane. Four cooling towers in El-Mahla El-Kubra city, Egypt are observed and studied. Two of them with height 56 m, and the others were 36 m height. The studied four towers have different cross-section diameters along the tower height. Each tower has a cone shape with a curved wall. The equation of the tower wall is determined using TLS observations and least squares adjustment techniques. The equations of cone projection with a curved wall are derived and presented in this paper. From TLS observations, the radii and accuracy of each 2 m tower height are determined with center coordinates, and then the inclination of the tower axis is calculated and drawn. From the results of TLS observations, data processing, and analysis using the suggested techniques, it is deduced that there is a deformation in tower walls with small values. The specified technique for observations collection and TLS data analysis through projection on a vertical plane is significant and valuable for determining the structural deformation of circular high rise buildings and towers. From the results, there are obvious deformation values in some cooling towers, so maintenance work must be included. The towers also must be checked and monitored several times at brief intervals. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
186. Cohomology of nonabelian embedding tensors on Hom-Lie algebras.
- Author
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Wen Teng, Jiulin Jin, and Yu Zhang
- Subjects
TENSOR algebra ,NONABELIAN groups ,ALGEBRA ,COHOMOLOGY theory ,INFINITESIMAL geometry - Abstract
In this paper, we generalize known results of nonabelian embedding tensor to the Hom setting. We introduce the concept of Hom-Leibniz-Lie algebra, which is the basic algebraic structure of nonabelian embedded tensors on Hom-Lie algebras and can also be regarded as a nonabelian generalization of Hom-Leibniz algebra. Moreover, we define a cohomology of nonabelian embedding tensors on Hom-Lie algebras with coeffcients in a suitable representation. The first cohomology group is used to describe infinitesimal deformations as an application. In addition, Nijenhuis elements are used to describe trivial infinitesimal deformations. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
187. Temporal Estimation of Non-Rigid Dynamic Human Point Cloud Sequence Using 3D Skeleton-Based Deformation for Compression.
- Author
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Kim, Jin-Kyum, Jang, Ye-Won, Lee, Sol, Hwang, Eui-Seok, and Seo, Young-Ho
- Subjects
POINT cloud ,VIDEO compression ,JOINTS (Anatomy) ,POINT set theory ,SKELETON ,HUMAN beings - Abstract
This paper proposes an algorithm for transmitting and reconstructing the estimated point cloud by temporally estimating a dynamic point cloud sequence. When a non-rigid 3D point cloud sequence (PCS) is input, the sequence is divided into groups of point cloud frames (PCFs), and a key PCF is selected. The 3D skeleton is predicted through 3D pose estimation, and the motion of the skeleton is estimated by analyzing the joints and bones of the 3D skeleton. For the deformation of the non-rigid human PC, the 3D PC model is transformed into a mesh model, and the key PCF is rigged using the 3D skeleton. After deforming the key PCF into the target PCF utilizing the motion vector of the estimated skeleton, the residual PC between the motion compensation PCF and the target PCF is generated. If there is a key PCF, the motion vector of the target PCF, and a residual PC, the target PCF can be reconstructed. Just as compression is performed using pixel correlation between frames in a 2D video, this paper compresses 3D PCFs by estimating the non-rigid 3D motion of a 3D object in a 3D PC. The proposed algorithm can be regarded as an extension of the 2D motion estimation of a rigid local region in a 2D plane to the 3D motion estimation of a non-rigid object (human) in 3D space. Experimental results show that the proposed method can successfully compress 3D PC sequences. If it is used together with a PC compression technique such as MPEG PCC (point cloud compression) in the future, a system with high compression efficiency may be configured. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
188. Analysis of shear flexible beams, using the meshless local Petrov‐Galerkin method, based on a locking‐free formulation
- Author
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Cho, J.Y. and Atluri, S.N.
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- 2001
- Full Text
- View/download PDF
189. Early systolic lengthening by speckle tracking echocardiography predicts outcome after coronary artery bypass surgery
- Author
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Sune Pedersen, Rasmus Mogelvang, Peter Søgaard, Tor Biering-Sørensen, Philip Brainin, Søren Galatius, Flemming Javier Olsen, Gunnar Gislason, Allan Iversen, Thomas Fritz-Hansen, and Søren Lindberg
- Subjects
ESL, early systolic lengthening ,IDI, integrated discrimination improvement ,medicine.medical_specialty ,medicine.medical_treatment ,Speckle tracking echocardiography ,030204 cardiovascular system & hematology ,Revascularization ,03 medical and health sciences ,Coronary artery bypass surgery ,0302 clinical medicine ,Euroscore ii ,Internal medicine ,LVEF, left ventricular ejection fraction ,Medicine ,Diseases of the circulatory (Cardiovascular) system ,030212 general & internal medicine ,A, late transmitral inflow velocity ,LV, left ventricular ,IQR, interquartile range ,Original Paper ,business.industry ,Proportional hazards model ,CABG, coronary artery bypass graft ,E, early transmitral inflow velocity ,Prognosis ,HR, hazard ratio ,Deformation ,medicine.anatomical_structure ,surgical procedures, operative ,Systolic lengthening ,NRI, net reclassification index ,RC666-701 ,Cardiology ,GLS, global longitudinal strain ,CK-MB, creatine kinase myocardial band ,e’, early diastolic tissue velocity ,Cardiology and Cardiovascular Medicine ,business ,Clinical risk factor ,Early systolic ,Artery - Abstract
Highlights • Early systolic lengthening (ESL) is a paradoxical lengthening of myocardial fibers. • Speckle tracking echocardiography is a common imaging tool for assessment of ESL. • ESL was a predictor of cardiovascular and all-cause death in CABG patients. • Specifically, the prognostic value of ESL was enhanced in women undergoing CABG., Background Early systolic lengthening (ESL), a paradoxical stretch of myocardial fibers, has been linked to loss of myocardial viability and contractile dysfunction. We assessed the long-term prognostic potential of ESL in coronary artery bypass graft (CABG) patients. Methods We retrospectively included patients (n = 709; mean age 68 years; 85% men) who underwent speckle tracking echocardiography (median 15 days) prior to CABG. Endpoints were cardiovascular death (CVD) and all-cause mortality. We assessed amplitude of ESL (%), defined as peak positive strain, and duration of ESL (ms), determined as time from Q-wave on the ECG to peak positive strain. We applied Cox models adjusted for clinical risk assessed as EuroSCORE II. Results During median follow-up of 3.8 years [IQR 2.7–4.9 years], 45 (6%) experienced CVD and 80 (11%) died. In survival analyses adjusted for EuroSCORE II, each 1% increase in amplitude of ESL was associated with CVD (HR 1.35 [95%CI 1.09–1.68], P = 0.006) and all-cause mortality (HR 1.29 [95%CI 1.08–1.54], P = 0.004). Similar findings applied to duration of ESL (per 10ms increase) and CVD (HR 1.12 [95%CI 1.02–1.23], P = 0.016) and all-cause mortality (HR 1.09 [95%CI 1.01––1.17], P = 0.031). The prognostic value of ESL amplitude was modified by sex (P interaction
- Published
- 2021
190. A stable algorithm for void growth and nucleation in transient, elasto‐plastic analysis of plate bending
- Author
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McDermott, P.M. and Kwon, Y.W.
- Published
- 2000
- Full Text
- View/download PDF
191. On volumetric locking of low‐order solid and solid‐shell elements for finite elastoviscoplastic deformations and selective reduced integration
- Author
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Doll, Stefan, Schweizerhof, Karl, Hauptmann, Ralf, and Freischläger, Christof
- Published
- 2000
- Full Text
- View/download PDF
192. Computations of an engine to analyze cylinder distortion
- Author
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Soua, Ali, Touratier, Maurice, and Polac, Laurent
- Published
- 1999
- Full Text
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193. Effects of Mechanical Signaling on Plant Cell Cytosolic Calcium
- Author
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Haley, Ann, Russell, Angela J., Wood, Nicola, Allan, Andrew C., Knight, Marc, Campbell, Anthony K., and Trewavas, Anthony J.
- Published
- 1995
194. Permafrost Early Deformation Signals before the Norilsk Oil Tank Collapse in Russia.
- Author
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Zhang, Peng, Chen, Yan, Ran, Youhua, and Chen, Yunping
- Subjects
OIL storage tanks ,PERMAFROST ,DEFORMATION of surfaces ,SYNTHETIC aperture radar ,DEFORMATIONS (Mechanics) - Abstract
Despite the profound roles of surface deformation monitoring techniques in observing permafrost surface stability, predetermining the approximate location and time of possibly occurring severe permafrost degradation before applying these techniques is extremely necessary, but has received little attention. Taking the oil tank collapse accident in the Norilsk region as a case, we explored this concern by analyzing the permafrost deformation mechanisms and determining early surface deformation signals. Regarding this case, we firstly applied the Small Baseline Subset Interferometric Synthetic Aperture Radar (SBAS-InSAR) technique to obtain its permafrost surface deformation rate, then utilized a sine model to decompose its interannual deformation and seasonal deformation, and finally compared the relationship between the topographic slope and deformation rate. Based on experimental results, we reveal that when the annual average temperature continuously increases at a rate of 2 ° C/year for 2∼3 consecutive years, permafrost areas with relatively large topographic slopes (>15 ° ) are more prone to severe surface deformation during the summer thaw period. Therefore, this paper suggests that permafrost areas with large topographic slopes (>15 ° ) should be taken as the key surveillance areas, and that the appropriate monitoring time for employing surface deformation monitoring techniques should be the summer thawing period after a continuous increase in annual average temperature at a rate of 2 ° C/year for 2∼3 years. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
195. Invisible Photonic Prints Shown by Deformation.
- Author
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Ye, Siyun, Fu, Qianqian, and Ge, Jianping
- Subjects
PHOTONIC crystals ,DEFORMATIONS (Mechanics) ,LITHOGRAPHY ,FRAUD prevention ,PRINTING - Abstract
Invisible photonic prints shown by deformation are prepared by soaking the mechanochromic photonic paper with crosslinker (PEGDA) and subsequently crosslinking part of the paper through a photo lithography process. The key point of this new technique is creating patterns and background with very close photonic structures but different mechanochromic capabilities, so that the invisible photonic patterns in relaxed state can be revealed under deformation due to the nonuniform change in photonic structure. Based on the relationship between crosslinking level and the reflection changes during deformation, one can conclude that a low crosslinking level favors the hiding of invisible patterns and a high crosslinking level favors the showing of patterns. The as-prepared samples can instantly and reversibly show the patterns by deformation and hide them by relaxation for many times, and the encapsulation by PDMS rubber prolongs its life time and enhances its durability in practical usages. The current printing technique is capable of creating invisible photonic prints in both macroscale and microscale range, which makes them potentially useful for security and antifraud applications in daily life. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
196. Insights into Deformation and Mechanism of a Reactivated Landslide Occurrence from Multi-Source Data: A Case Study in Li County, China.
- Author
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Du, Yingjin, He, Kun, Hu, Xiewen, and Ma, Hongsheng
- Subjects
LANDSLIDES ,ROAD construction ,RAINFALL ,NATURAL disaster warning systems - Abstract
The investigation of reactivated landslides in the alpine-canyon areas suffers the difficult accessibility of precipitous terrain. In particular, when reactivated landslides occur along the major roads, efforts are focused on measuring ground surface displacements during road construction. Nevertheless, the ancient landslide deposits may reactivate after several years of road operation, while they show a stable state during the road construction. The characterization of this type of reactivated landslides is challenging, due to their complex mechanism and the limited monitoring data. Appropriate multi-source data can provide insights into deformation fields and enhance the understanding of landslide mechanisms, ensuring the outperformance of remedial works. This paper reports a recent Tangjiawan reactivated landslide along the Wenchuan-Maerkang Highway in Li County, China. The outcomes, including satellite InSAR, in situ real-time monitoring, and detailed ground and UAV investigation, conducted at this landslide are presented. Early deformation of the reactivated landslide began from 2019, with an InSAR-derived velocity of −11.7 mm/year, furthermore, a significant subsidence of about 21.2 mm, which occurred within a span of only 12 days from 3 June 2020 to 15 June 2020, was observed. The deformation characteristics derived from in situ monitoring during the remedial works were likely firstly associated with the initial unreinforced slope condition and the heavy rainfall. Subsequently, the displacement evolution transformed into deformation induced by time-dependent reduction in slope strength under rainfall conditions. The existing of unconsolidated deposits derived from ancient landslides, along with a fragile geo-structure consisting of rock blocks and gravels interlayered with breccias, exacerbated by large relief created a predisposition for landslide reactivation. Furthermore, 13 days of antecedent cumulative rainfall totaling 224.5 mm directly triggered the occurrence of a landslide event. The significance and implications of integrating multiple monitoring techniques are emphasized. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
197. Application of Stereo Digital Image Correlation on Facial Expressions Sensing.
- Author
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Cheng, Xuanshi, Wang, Shibin, Wei, Huixin, Sun, Xin, Xin, Lipan, Li, Linan, Li, Chuanwei, and Wang, Zhiyong
- Subjects
DIGITAL image correlation ,FACIAL expression ,STEREO image ,EMOTIONS ,DIGITAL images - Abstract
Facial expression is an important way to reflect human emotions and it represents a dynamic deformation process. Analyzing facial movements is an effective means of understanding expressions. However, there is currently a lack of methods capable of analyzing the dynamic details of full-field deformation in expressions. In this paper, in order to enable effective dynamic analysis of expressions, a classic optical measuring method called stereo digital image correlation (stereo-DIC or 3D-DIC) is employed to analyze the deformation fields of facial expressions. The forming processes of six basic facial expressions of certain experimental subjects are analyzed through the displacement and strain fields calculated by 3D-DIC. The displacement fields of each expression exhibit strong consistency with the action units (AUs) defined by the classical Facial Action Coding System (FACS). Moreover, it is shown that the gradient of the displacement, i.e., the strain fields, offers special advantages in characterizing facial expressions due to their localized nature, effectively sensing the nuanced dynamics of facial movements. By processing extensive data, this study demonstrates two featured regions in six basic expressions, one where deformation begins and the other where deformation is most severe. Based on these two regions, the temporal evolutions of the six basic expressions are discussed. The presented investigations demonstrate the superior performance of 3D-DIC in the quantitative analysis of facial expressions. The proposed analytical strategy might have potential value in objectively characterizing human expressions based on quantitative measurement. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
198. Semianalytical Method for Controlling the Deformation of Retaining Structures Subjected to Asymmetrical Loads.
- Author
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Ding, Haibin, Wan, Qiwei, Xu, Changjie, Fan, Xiaozhen, and Tong, Lihong
- Subjects
BUILDING foundations ,STRAINS & stresses (Mechanics) ,EARTH pressure ,DEFORMATIONS (Mechanics) ,SUBWAY stations ,BORED piles ,STATIC pressure - Abstract
In excavation engineering, most of the retaining structures are subjected to asymmetrical loads, including in asymmetrical excavation and asymmetrical overloading. However, a theoretical solution to, and deformation-controlling method for, this problem has remained elusive to date. In this work, a semianalytical solution for determining the deformation of retaining structures subjected to asymmetrical loads was derived based on the principle of minimum potential energy. The retaining structures were viewed as flexible, and the overall deformation of the retaining system was evaluated by our proposed theoretical model. This model was verified by comparing it with practical monitoring data. Subsequently, the theoretical solution was applied to analyze the stress and deformation characteristics under the conditions of asymmetrical excavation and asymmetrical overloading, which can be controlled to ensure the safety of a project. Finally, because of the requirement for a small amount of deformation in the foundation pit retaining piles, the earth pressure on the retaining piles is close to the static earth pressure. Reducing the length of the retaining pile on one side had a greater influence on the deformation on that side, but less of an influence on the other side. Thus, the proposed model can be used for optimizing the asymmetrical design of a retaining structure in order to balance the economy and safety of a project. Our design theory can be applied to a variety of engineering projects. A typical case is the Guangzhou Baiyun District Comprehensive Transportation Hub Project in China. The method was used to analyze the status of the subway foundation pit, offering a new design scheme to reduce the design length of the retaining piles, which resulted in great economic benefits in its practical application. The findings provided in this paper can be applied to the engineering of any long, narrow foundation pit that can be simplified into a two-dimensional plane–strain calculation model, being used to realize more accurate deformation control over the foundation pit envelope. The core of this calculation method is that it can accurately describe the magnitude of the earth pressure. The distribution of the earth pressure is worthy of further study. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
199. Analytical Solution for the Deformation of Pipe Galleries Adjacent to Deep Excavation.
- Author
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Xiang, Binhui, Liu, Ying, Cui, Jifei, and Yang, Zhenkun
- Subjects
ANALYTICAL solutions ,EXCAVATION ,BURIED pipes (Engineering) ,UNDERGROUND construction ,SOIL solutions ,ROCK deformation - Abstract
Deep excavations clearly impact adjacent existing properties and threaten their operational safety. Predicting the deformation of existing infrastructure induced by nearby underground construction is the main concern of urban underground development. This paper presents an analytical calculation method for predicting underground pipe gallery deformations induced by adjacent deep excavations. First, the authors assume the existing pipe gallery to be nonexistent in the soil and propose a solution to calculate the excavation-induced vertical movements of the soil at the position of the existing pipe gallery. Thereafter, the authors simplify the existing pipe gallery as an elastic beam on a Winkler foundation to calculate its deformation. Finally, the method is verified by the good agreement found between the calculated result and the field measurement of the construction of the Shanghai Hongqiao CBD project. The proposed analytical method of this work can provide accurate evaluation results for similar engineering projects. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
200. Quality Index for Assessment of the Mechanical Condition of Transformers' Active Part with Frequency Response and Vibroacoustic Measurements.
- Author
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Kornatowski, Eugeniusz, Banaszak, Szymon, and Molenda, Paweł
- Subjects
TEST methods - Abstract
The paper describes the application of the numerical tool quality index for an objective evaluation of complementary frequency response analysis (FRA) and vibroacoustic method (VM) test methods. These diagnostic methods are used in the industrial practice of transformer diagnostics for the assessment of the mechanical condition of windings and a core. The quality index is based on a numerical comparison of the curve obtained from measurements and the reference curve in a frequency domain. The quality index is based on estimators for the covariance, variance, and expected values. First, both methods of analysis were applied to a group of transformers of similar construction, leading conclusions on quality index values being quickly drawn. Next, it was applied to another transformer's FRA and VM measurement results. The results showed problems with its mechanical condition, thus confirming that the proposed methods can be used in the practical assessment of transformers with these two diagnostic methods. The assessment of transformer's active-part mechanical condition with complementary FRA and VM methods can be performed much more easily with the proposed quality indices. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
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