scholarly journals Image-Based Underwater Inspection System for Abrasion of Stilling Basin Slabs of Dam

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Yonglong Li ◽  
Hua Zhang ◽  
Shuang Wang ◽  
Haoran Wang ◽  
Jialong Li
Keyword(s):  
Field Experiments ◽  
Concrete Surface ◽  
Inspection System ◽  
Underwater Robot ◽  
Stilling Basin ◽  
Underwater Image ◽  
Surface Damages ◽  
Quantitative Analysis Method ◽  
Exposure Ratio ◽  
Periodic Inspections

The abrasion of stilling basin slabs which is caused by waterborne particles is one of the main surface damages in the operation of hydropower station. For determining whether to repair the stilling basin slabs, periodic inspections of erosion condition of stilling basin slabs are required. The practical problem is how to get the underwater image without unwatering and how to analyse the abrasion though the images. This paper developed a novel underwater inspection system named UIS-1 which consists of a customized underwater robot and special quantitative analysis method for this situation. Firstly, the integrated component was designed for the underwater robot that partially removes the siltation and obtains the image of the concrete surface of stilling basin slabs in the desired position. Secondly, the paper proposed an image algorithm to obtain aggregate exposure ratio for quantitative abrasion analysis. This image algorithm used SLIC superpixel and the SVM machine learning method to detect the coarse aggregate exposure automatically. Then, the aggregate exposure ratio was calculated to analyse the degree of abrasion. Finally, the UIS-1 system was evaluated in the field experiments of a dam in Sichuan, China, and its performance was discussed by comparison.

Lateral coefficient of friction for characterizing winter road conditions

2016 ◽  
Vol 43 (1) ◽  
pp. 73-83 ◽  
Author(s):  
Sahar Salimi ◽  
Somayeh Nassiri ◽  
Alireza Bayat ◽  
Don Halliday
Keyword(s):  
Field Experiments ◽  
Surface Friction ◽  
Concrete Surface ◽  
Snow Accumulation ◽  
Frictional Heat ◽  
Vehicle Speed ◽  
Test Road ◽  
Winter Road ◽  
Friction Measurements ◽  
The University

Real Time Traction Tool (RT3)-Curve was used in this study to evaluate the effect of ice and snow on tire–road lateral friction coefficient, herein referred to as the Halliday Friction Number (HFN). The field experiments for the study were performed in winter 2012–2013 on the University of Alberta’s test road facility in Edmonton, Alberta. Each run was repeated at three target speeds under varied road conditions, bare dry, dry with ice patches, ice, and three levels of snow accumulation. No considerable correlation was found between vehicle speed and the friction measurements for bare dry, ice- and snow-covered conditions. Expectedly, the bare dry asphalt concrete surface had the highest HFN, the presence of ice reduced the dry surface friction by 55%. The accumulation of snow on the dry surface reduced the HFN further than ice, by 69, 75, and 81% for light, moderate, and heavy snow, respectively. A falling trend was observed for friction as more snow accumulated on the ground. Analysis of the effect of number of truck passes over ice at −3.5 and −5 °C showed that ice can become more slippery after each pass of traffic. A similar analysis for snow revealed that more passes over moderate snow will compact the fresh snow into a slippery surface. For light snow, even at low temperatures (<−10 °C), passes of traffic will melt the snow through frictional heat and result in higher friction values.

scholarly journals Field Experiments of Underwater Image Transmission for AUV

2020 ◽  
Vol 25 ◽  
pp. 171-174
Author(s):  
Shinsuke Yasukawa ◽  
Yuya Nishida ◽  
Jonghyun Ahn ◽  
Takashi Sonoda ◽  
Kentaro Yanagise ◽  
...  
Keyword(s):  
Field Experiments ◽  
Image Transmission ◽  
Underwater Image

Experimental and Application Study of a New Type High Strength Repairing Mortar for Hydraulic Concrete

2013 ◽  
Vol 387 ◽  
pp. 72-76 ◽  
Author(s):  
Fei Wu ◽  
Chao Hua Jiang ◽  
Ying Di Liao ◽  
Li Jun Hou
Keyword(s):  
Quality Control ◽  
High Strength ◽  
Concrete Surface ◽  
Repair Process ◽  
Good Mechanical Property ◽  
Construction Technology ◽  
Bonding Performance ◽  
Hydraulic Concrete ◽  
Surface Damages ◽  
Repairing Effect

Be aimed at concrete surface damages of hydraulic concrete structures, a high strength repairing mortar was made in this paper. The mechanical properties and durability of repairing mortar were studied. Samples of repairing mortar preparation in laboratory and in field were tested respectively and its repair process and quality control was discussed. The results show that the repairing mortar has good mechanical property, obviously anti-abrasion property and excellent bonding performance. It can play an important role in concrete repairing in the field of hydraulic engineering. The sample property from field is a little lower than of laboratory made but still superior to design index. To achieve good repairing effect, construction technology and quality control is also the important factor.

Development of an inspection system for cracks in a concrete tunnel lining

2007 ◽  
Vol 34 (8) ◽  
pp. 966-975 ◽  
Author(s):  
Seung Yeol Lee ◽  
Sang Ho Lee ◽  
Dong Ik Shin ◽  
Young Kap Son ◽  
Chang Soo Han
Keyword(s):  
Image Processing ◽  
Image Data ◽  
Tunnel Lining ◽  
Inspection System ◽  
Visual Methods ◽  
Charge Coupled Device ◽  
Nondestructive Tests ◽  
Series Of Experiments ◽  
Analysis System ◽  
Periodic Inspections

Over the last several decades, many concrete tunnels have been constructed for roads, highways, and railways. For safety in concrete tunnels, periodic inspections have been conducted using nondestructive testing technologies and techniques. However, nondestructive tests cannot replace visual inspection because of their slow and complicated procedures. For this reason, their use has been limited to precision inspections. Visual methods of assessment also require significant time commitments, and they produce subjective results regarding measured crack data. This study proposes an inspection system for the rapid measurement of cracks in tunnel linings and provides an objective method for assessing crack data for safety purposes. The system consists of both image data acquisition and analysis systems. The acquisition system takes images with charge-coupled device (CCD) line-scan cameras. The analysis system extracts crack information from the acquired images using image processing. Measured crack information includes the thickness, length, and orientation of cracks. To improve the accuracy of crack recognition, the geometric properties and patterns of cracks in concrete structures should be applied to image processing. This proposed system was verified through a series of experiments in both laboratory and field environments. Key words: crack, inspection, image processing, tunnel lining, tunnel safety.

Underwater Image Mosaicking using Underwater Robot

2004 ◽  
Vol 2004 (0) ◽  
pp. 114
Author(s):  
H Sakai ◽  
T Tanaka ◽  
S Ohata ◽  
K Ishii ◽  
T Ura
Keyword(s):  
Underwater Robot ◽  
Image Mosaicking ◽  
Underwater Image

Automatic Crack Length Measurement of Concrete Structure Based on Image Processing

2014 ◽  
Vol 1030-1032 ◽  
pp. 728-731 ◽  
Author(s):  
Qi Zi Huang Peng ◽  
Wen Wei Huang ◽  
Ying Lu
Keyword(s):  
Image Processing ◽  
Crack Length ◽  
Concrete Structure ◽  
Concrete Surface ◽  
Length Measurement ◽  
Inspection System ◽  
Time Varying ◽  
Structural Surface ◽  
The Stability ◽  
Crack Length Measurement

The safety of concrete structure can be evaluated by manual survey through the visible crack shown on structural surface, but the manual survey is costly and time-consuming. To improve this, a novel image-based crack length measurement is proposed. The method starts with getting time varying crack images by proposed inspection system. Then retrieve crack skeleton from crack images by pre-processing, and construct crack skeleton of tree structure. After getting crack trunk by pruning small edges from crack skeleton, the length of crack is figure out. This method can measure crack length automatically, which will make contribution to enhance the stability, durability and safety of concrete structure. The validity and accuracy of the proposed method was tested by an experiment using images of a real concrete surface.

scholarly journals Measurement of Thinned Water-Cooled Wall in a Circulating Fluidized Bed Boiler Using Ultrasonic and Magnetic Methods

2021 ◽  
Vol 11 (6) ◽  
pp. 2498
Author(s):  
Jinyi Lee ◽  
Eunho Choe ◽  
Cong-Thuong Pham ◽  
Minhhuy Le
Keyword(s):  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Magnetic Sensors ◽  
Magnetic Flux Density ◽  
Inspection System ◽  
Measured Signal ◽  
Cross Sectional ◽  
Ultrasonic Probe ◽  
Ultrasonic Methods ◽  
Surface Damages

In this paper, a nondestructive inspection system is proposed to detect and quantitatively evaluate the size of the near- and far-side damages on the tube, membrane, and weld of the water-cooled wall in the fluidized bed boiler. The shape and size of the surface damages can be evaluated from the magnetic flux density distribution measured by the magnetic sensor array on one side from the center of the magnetizer. The magnetic sensors were arrayed on a curved shape probe according to the tube’s cross-sectional shape, membrane, and weld. On the other hand, the couplant was doped to the water-cooled wall, and a thin film was formed thereon by polyethylene terephthalate. Then, the measured signal of the flexible ultrasonic probe was used to detect and evaluate the depth of the damages. The combination of the magnetic and ultrasonic methods helps to detect and evaluate both near and far-side damages. Near-side damages with a minimum depth of 0.3 mm were detected, and the depth from the surface of the far-side damage was evaluated with a standard deviation of 0.089 mm.

scholarly journals Analysis of Mechanical Adhesion Climbing Robot Design for Wind Tower Inspection

2021 ◽  
Author(s):  
Shyamal Chandra Mondal ◽  
Patricio l. C. Marquez ◽  
Mohammad Osman Tokhi
Keyword(s):  
Wind Turbine ◽  
Inspection System ◽  
Robot Design ◽  
Potential Hazard ◽  
Climbing Robot ◽  
Mechanical Adhesion ◽  
Inspection Tasks ◽  
Control System Model ◽  
Different Diameters ◽  
Periodic Inspections

Mmaintenance of wind turbine farms is a huge task, with associated significant risks and potential hazard to the safety and wellbeing of people who are responsible for carrying the tower inspection tasks. Periodic inspections are required for wind turbine tower to ensure that the wind turbines are in full working order, with no signs of potential failure. Therefore, the development of an automated wind tower inspection system has been very crucial for the overall performance of the renewable wind power generation industry. In order to determine the life span of the tower, an investigation of robot design is discussed in this paper. It presents how a mechanical spring-loaded climbing robot can be designed and constructed to climb and rotate 360° around the tower. An adjustable circular shape robot is designed that allows the device to fit in different diameters of the wind generator tower. The rotational module is designed to allow the wheels to rotate and be able to go in a circular motion. The design further incorporates a suspension that allows the robot to go through any obstacle. This paper also presents afiniteelement spring stress analysis and Simulink control system model to find the optimal parameters that are required for the wind tower climbing robot.

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