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The characteristic analysis of temperature sensor based on a fabricated microstructure fiber by digital image processing technique and finite element method

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JOURNAL OF PHYSICS D-APPLIED PHYSICS 2020年第17期53卷 175108-175108页

作者： Zhang, Song Li, Shuguang Wang, Shun Guo, Ying Zhou, Xue Yanshan Univ Sch Sci State Key Lab Metastable Mat Sci & Technol Qinhuangdao 066004 Hebei Peoples R China Yanshan Univ Sch Sci Key Lab Microstruct Mat Phys Hebei Prov Qinhuangdao 066004 Hebei Peoples R China Northeastern Univ Coll Informat Sci & Engn State Key Lab Synthet Automat Proc Ind Shenyang 110819 Peoples R China

A temperature sensor based on a Sagnac interferometer by the actual microstructure fiber (MSF) selectively filled with ethanol has been designed in this paper. We obtained the vectorized cross-section of MSF using the method of the digital image processing technique and the finite element method. This method can model the actual cross section structure of MSF rapidly by gray scale processing, filtering, threshold, and edge detection and be applied to the calculation and simulation of the actual MSF perfectly. The air holes on both sides of the core were filled with ethanol to improve the birefringence of the MSF. The simulation result showed that the dip wavelength in transmission spectrum has a blue-shift when the temperature increasing. The average sensitivity can be up to 1 nm degrees C-1 as the temperature rises from 25 degrees C to 75 degrees C. It can be tested in a wide temperature range, which plays a profound role in practical application.

关键词： Sagnac interferometer microstructure fiber temperature sensor digital image processing technique

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Numerical investigation on fracture evolution of asphalt mixture compared with acoustic emission

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INTERNATIONAL JOURNAL OF PAVEMENT ENGINEERING 2022年第10期23卷 3481-3491页

作者： Wei, Hui Li, Jue Wang, Feiyue Zheng, Jianlong Tao, Yiyang Zhang, Yuhao Changsha Univ Sci & Technol Sch Traff & Transportat Engn Changsha Peoples R China Changsha Univ Sci & Technol State Engn Lab Highway Maintenance Technol Changsha Peoples R China Cent South Univ Sch Civil Engn Changsha Peoples R China Henan Normal Univ Xinlian Coll Zhengzhou Peoples R China

To reveal the fracture damage of asphalt mixture, an image-based numerical approach is proposed in this study considering the distribution of aggregate and asphalt mortar. Both digital image processing technique and discrete element method are applied to simulate the inhomogeneity of specimen and its fracture evolution at low temperature. At the same time, the acoustic emission (AE) activities are measured in laboratory to be compared with the micromechanical responses of numerical models. Results indicate that the developed method is suitable for modelling the numerical specimen of asphalt mixture, taking into account the size gradation and morphology of aggregates in the two-dimensional image. The numerical results of asphalt mixture have a good agreement with that of laboratory tests in cracking distribution and statistical probability. Cracks first appear on the aggregate-mortar interface, located in the upper and middle parts of the specimen, and then the brittle shear failure gradually propagates along the surface. Cumulative probabilities of both AE ringing counts and microfracture number follow the Weibull distribution. The numerical model has a significant advantage in the fracture evolution of asphalt mixture because the eccentric loading is unavoidable in laboratory tests due to personal and mechanical errors.

关键词： Asphalt mixture fracture evolution discrete element method digital image processing technique acoustic emission activity

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Investigation of corrosion-induced cracks using corrosion products quantified by an X-ray technique and FE analysis of single- and multiple-rebar beams

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CEMENT & CONCRETE COMPOSITES 2024年 151卷

作者： Xu, Zhejun Akiyama, Mitsuyoshi Lim, Sopokhem Srivaranun, Supasit Frangopol, Dan M. Miyazato, Shinichi Li, Ao Waseda Univ Dept Civil & Environm Engn Tokyo Japan Kasetsart Univ Dept Civil Engn Bangkok Thailand Lehigh Univ Dept Civil & Environm Engn ATLSS Ctr Bethlehem PA USA Kanazawa Inst Technol Dept Civil & Environm Engn Nonoichi Japan

The effects of corrosion methods, galvanostatic (GS) vs. artificial climate environment (ACE), on the relationships between corrosion products and corrosion cracks of corroded reinforced concrete beams are investigated. The experimental results show that the GS method induces smaller corrosion crack width. A novel quantitative detection method of corrosion product thickness using X-ray and digital image processing techniques is proposed for investigating the continuous development of corrosion products. As the corrosion level increases, a smaller steel-to-rust volume expansion ratio caused by continuous leakage and a lower oxidation degree of corrosion products for the GS specimens are the major reasons for the smaller corrosion cracks. Regarding the effect of rebar arrangement on the development of corrosion-induced cracks, the expansion stress from corner-located rebars restrained the growth of corrosion products and further limited the propagation of corrosion-induced cracks of the center rebar. Estimated corrosion crack width via FE analysis using measured corrosion products as input show good agreement with experimental results.

关键词： Corrosion products X-ray technology digital image processing technique Corrosion-induced cracks FE analysis

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Study on the optimal compaction effort of asphalt mixture based on the distribution of contact points of coarse aggregates

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ROAD MATERIALS AND PAVEMENT DESIGN 2021年第7期22卷 1594-1615页

作者： Cai, Xu Wu, Kuanghuai Huang, Wenke Guangzhou Univ Sch Civil Engn Guangzhou Peoples R China

Compaction effort significantly influences the skeleton characteristics of asphalt mixture, and mixtures of different skeletons show widely varying demands for compaction effort. Based on a digital image processing technique, this study characterises the skeleton characteristics of asphalt mixture under various cycles of compaction repetitions by introducing coarse aggregate contact points, aggregate inclination and some other indexes. A meso-macro perspective is taken to analyse the variation in the aggregate skeleton of asphalt mixtures during compaction. Furthermore, this study conducts a non-standard rutting test to verify the high-temperature stability of the material, and establishes a correlation between the compaction effort and the stability parameter of the skeleton of an asphalt mixture. As indicated by the test results, gradation can determine the value of asphalt mixture's CEP25 (compaction energy parameters under 25 compaction repetitions) and the growth trend of CEP (compaction energy parameters). When compaction effort exceeds the bearing capacity limit of the skeleton, the reduction of coarse aggregate particles, the decrease in the number of contact points and the fluctuation in aggregate inclination are observed. With an increase in compaction repetitions, average coordination number and contact points N-a first increase and then decrease, but the compaction repetitions to the peak values are different. According to the results of a non-standard rutting test, an increase in compactness can strengthen the rutting resistance of asphalt mixture, but this conclusion does not suitable for skeleton void-type mixtures. The established CEP calculation model can reflect the influence of gradation on compaction effort, and the compaction effort calculated from contact point number N-a has a fairly good correlation with the test results.

关键词： asphalt mixture optimal compaction effort model skeleton structure contact points digital image processing technique

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Study on the dynamic mechanism of soil desiccation cracking by surface strain/displacement analysis

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COMPUTERS AND GEOTECHNICS 2022年 152卷

作者： Tang, Chao-Sheng Cheng, Qing Lin, Luan Tian, Ben -Gang Zeng, Hao Shi, Bin Nanjing Univ Sch Earth Sci & Engn 163 Xianlin Ave Nanjing Peoples R China

digital camera was used to record the dynamic process of soil desiccation cracks in real time. With application of image processing technique, the relationship between the strain/displacement field and desiccation cracking were analyzed. Results show that the crack usually occurs at locations where tensile strain concentrates. After the crack is generated, the surrounding strain field and displacement field are rapidly redistributed. The new strain field and displacement field act on the crack again, affecting the propagation direction of the crack. Under the interaction between the strain/displacement field and cracks, the crack tends to intersect with other cracks at right angles and deflection may occur in the development process. The soil is divided into different clods by the cracks. Each clod centripetally shrinks and has a shrinkage center which may move with elapsed drying time. Based on the strain/displacement field, the characteristics of desiccation cracking in local area of soil can be predicted in advance and it can be used to directly judge the activeness of the cracks or clods. The digital image processing technique can effectively obtain the soil deformation without disturbing the soil sample, which offers an available way for understanding the intrinsic dynamic mechanisms of soil desiccation cracking.

关键词： Soil desiccation cracking digital image processing technique Shrinkage center Strain field Displacement field

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Quantitative characterization of joint roughness based on semivariogram parameters

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INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES 2018年 109卷 1-8页

作者： Zhao Lianheng Zhang Shuaihao Huang Dongliang Zuo Shi Li Dejian Cent S Univ Sch Civil Engn Changsha 410075 Hunan Peoples R China Cent S Univ Minist Educ Key Lab Heavy Haul Railway Engn Struct Changsha 410075 Hunan Peoples R China

The joint roughness coefficient (JRC) is an index defined by geometrical characteristics and correlated to mechanical shear strength. It is empirical and subjective to evaluate JRC by visual comparison. The existing quantitative evaluations of joint roughness are based on statistical parameters (i.e., the root mean square Z(2), the structure function SF, and the textural parameter R-P), which fail to describe the spatial variability of joint profiles. This paper presents a novel roughness descriptor, semivariogram parameter CA, to quantify roughness characteristics. Based on the theory of geostatistics, a semivariogram function is established. Furthermore, a Gaussian fitting model is applied to obtain the semivariogram parameter CA and its empirical equation, which can be used to evaluate the joint roughness coefficient. Finally, to verify the feasibility of this method, a comparison has been conducted between statistical parameters and the semivariogram parameter for the analysis of Barton's ten standard JRC profiles and 102 additional rock joint profiles.

关键词： Rock joint Joint roughness coefficient (JRC) Variogram Quantitative estimation digital image processing technique

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Analysis of Kinematic Parameters and Driver Behavior at Turbo Roundabouts

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JOURNAL OF TRANSPORTATION ENGINEERING PART A-SYSTEMS 2018年第6期144卷 4018020.1-4018020.12页

作者： Guerrieri, Marco Mauro, Raffaele Parla, Giuseppe Tollazzi, Tomaz Univ Palermo Polytech Sch I-90144 Palermo Italy Univ Trento Dept Civil Environm & Mech Engn I-38123 Trento Italy Via G Pitre 3 I-93100 Caltanissetta Italy Univ Maribor Dept Roads & Traff Maribor 2000 Slovenia

This study focuses on both vehicle kinematic parameters (speed and acceleration) and behavior parameters (critical interval and follow-up time) of drivers at turbo-roundabouts. Empirical evaluations of such parameters can be helpful in calibrating traffic microsimulation models or assigning behavior parameters to closed-form capacity models in turbo-roundabouts (gap-acceptance capacity models) and are also related to evaluation of vehicles pollutant emissions. The research was based on traffic process observed in the first turbo-roundabout implemented in the city of Maribor in Slovenia. In 2016 a great number of traffic samples were taken with high-frame-rate video recordings [>50 frames per second (fps)]. All vehicle trajectories were obtained with the methods and algorithms typical of the digital imageprocessing technique (DIP) by filtering the discrete signal of vehicle trajectories f(t)with wavelet analysis. The research results showed that vehicle speeds on entry lanes are rather moderate (below 25 km/h, 15 m prior to the Yield line), whereas accelerations usually have values inferior to 2 m/s(2) on arm lanes and to 1.5 m/s(2) on ring lanes. The critical intervals t(c) [distributed according to an Erlang probability distribution function (PDF)] and follow-up headways t(f) (distributed according to an inverse Gaussian PDF) have, on the other hand, values in ranges of t(c) = 4.03-5.48 s and t(f) = 2.52-2.71 s, respectively, according to the right-or left-turn lane and to the major or minor entry in question. (C) 2018 American Society of Civil Engineers.

关键词： Turbo-roundabout Traffic processes Driver behavior digital image processing technique

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Multi-point displacement monitoring of bridges using a vision-based approach

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WIND AND STRUCTURES 2015年第2期20卷 315-326页

作者： Ye, X. W. Yi, Ting-Hua Dong, C. Z. Liu, T. Bai, H. Zhejiang Univ Dept Civil Engn Hangzhou 310058 Zhejiang Peoples R China Dalian Univ Technol Sch Civil Engn Dalian 116023 Peoples R China Tangram Elect Engn Co Ltd Beijing 100088 Peoples R China

To overcome the drawbacks of the traditional contact-type sensor for structural displacement measurement, the vision-based technology with the aid of the digital image processing algorithm has received increasing concerns from the community of structural health monitoring (SHM). The advanced vision-based system has been widely used to measure the structural displacement of civil engineering structures due to its overwhelming merits of non-contact, long-distance, and high-resolution. However, seldom currently-available vision-based systems are capable of realizing the synchronous structural displacement measurement for multiple points on the investigated structure. In this paper, the method for vision-based multi-point structural displacement measurement is presented. A series of moving loading experiments on a scale arch bridge model are carried out to validate the accuracy and reliability of the vision-based system for multi-point structural displacement measurement. The structural displacements of five points on the bridge deck are measured by the vision-based system and compared with those obtained by the linear variable differential transformer (LVDT). The comparative study demonstrates that the vision-based system is deemed to be an effective and reliable means for multi-point structural displacement measurement.

关键词： structural health monitoring dynamic displacement vision-based system digital image processing technique pattern matching algorithm

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Comparison Analysis of the Aggregate Contact Characteristics between Skeleton-dense and Suspended-dense Structure Asphalt Mixture

Comparison Analysis of the Aggregate Contact Characteristics...

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2nd International Conference on Mechanical Engineering, Materials Science and Civil Engineering (ICMEMSCE 2013)

作者： Shi, Liwan Wang, Duanyi Julius, Masley Zhang, Shuwen S China Univ Technol Sch Civil Engn & Transportat Guangzhou 510006 Guangdong Peoples R China

ISBN: (纸本)9783037859612

The contact between aggregates is an important feature of asphalt mixture skeleton. By comparing skeleton-dense and suspended-dense structure asphalt mixture test results, this paper studied the distribution characteristics of coarse aggregate contacts by using two-dimension digital image processing technique. The results indicate that skeleton-dense asphalt mixture has more homogeneous distribution of contact points, and a relatively stable skeleton structure than suspended-dense mixture. In two-dimension image, homogeneous distribution of contact points and little "unrestrained" coarse aggregates are two evident characteristics of asphalt mixture with good rutting resistance. The rutting resistance of asphalt mixture has no correlation with contact points, but is related to the spatial distribution of the contact points.

关键词： Asphalt mixture Aggregate contact characteristics digital image processing technique Skeleton-dense structure Suspended-dense structure

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Automated drusen detection in retinal images using analytical modelling algorithms

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BIOMEDICAL ENGINEERING ONLINE 2011年第1期10卷 1-16页

作者： Mora, Andre D. Vieira, Pedro M. Manivannan, Ayyakkannu Fonseca, Jose M. Univ Nova Lisboa Ctr Technol & Syst P-2829516 Caparica Portugal Univ Nova Lisboa Dept Electrotech Engn Fac Sci & Technol P-2829516 Caparica Portugal Univ Nova Lisboa Dept Phys Fac Sci & Technol P-2829516 Caparica Portugal NHS Grampian NHS Grampian Dept Biomed Phys & Bioengn Aberdeen AB25 2ZD Scotland Univ Aberdeen Aberdeen AB25 2ZD Scotland

Background: Drusen are common features in the ageing macula associated with exudative Age-Related Macular Degeneration (ARMD). They are visible in retinal images and their quantitative analysis is important in the follow up of the ARMD. However, their evaluation is fastidious and difficult to reproduce when performed manually. Methods: This article proposes a methodology for Automatic Drusen Deposits Detection and quantification in Retinal images (AD3RI) by using digital image processing techniques. It includes an image pre-processing method to correct the uneven illumination and to normalize the intensity contrast with smoothing splines. The drusen detection uses a gradient based segmentation algorithm that isolates drusen and provides basic drusen characterization to the modelling stage. The detected drusen are then fitted by Modified Gaussian functions, producing a model of the image that is used to evaluate the affected area. Twenty two images were graded by eight experts, with the aid of a custom made software and compared with AD3RI. This comparison was based both on the total area and on the pixel-to-pixel analysis. The coefficient of variation, the intraclass correlation coefficient, the sensitivity, the specificity and the kappa coefficient were calculated. Results: The ground truth used in this study was the experts' average grading. In order to evaluate the proposed methodology three indicators were defined: AD3RI compared to the ground truth (A2G);each expert compared to the other experts (E2E) and a standard Global Threshold method compared to the ground truth (T2G). The results obtained for the three indicators, A2G, E2E and T2G, were: coefficient of variation 28.8 %, 22.5 % and 41.1 %, intraclass correlation coefficient 0.92, 0.88 and 0.67, sensitivity 0.68, 0.67 and 0.74, specificity 0.96, 0.97 and 0.94, and kappa coefficient 0.58, 0.60 and 0.49, respectively. Conclusions: The gradings produced by AD3RI obtained an agreement with the ground truth sim

关键词： Kappa Coefficient Retinal image digital image processing technique Illumination Pattern Gradient Path

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