Evaluation on the behavior and contributing factors of subsidence in the intersection area of Expwy 78 and Taiwan High Speed Rail based on in situ monitoring and numerical simulations

2020 ◽  
Vol 79 (6) ◽  
pp. 2971-2995
Author(s):  
Muhsiung Chang ◽  
Togani Cahyadi Upomo ◽  
Ren-Chung Huang ◽  
Po-Kai Wu ◽  
Pai-Chia Su
Keyword(s):  
Numerical Simulations ◽  
High Speed ◽  
In Situ Monitoring ◽  
Contributing Factors ◽  
High Speed Rail ◽  
Intersection Area

scholarly journals Microstructure Refinement on Crevice Corrosion of High-Speed Rail Steel U75V Visualized by an In Situ Monitoring System

2022 ◽  
Vol 8 ◽  
Author(s):  
Jian Wang ◽  
Binbin Zhang ◽  
Weichen Xu ◽  
Jie Zhang ◽  
Lihui Yang ◽  
...  
Keyword(s):  
Crevice Corrosion ◽  
High Speed ◽  
Rail Steel ◽  
In Situ Monitoring ◽  
Metal Loss ◽  
General Corrosion ◽  
High Speed Rail ◽  
Cooling Rates ◽  
Microstructure Refinement

Rail foot covered by a fastener will suffer from crevice corrosion, leading to thinning and localized attack of crevice interior posing a risk of failure. This work investigated crevice corrosion behavior of a typical pearlitic high-speed rail steel U75V, focusing for the first time on the effect of pearlitic microstructure refinement achieved by heat treatment with different cooling rates 2, 5, and 10°C/s. Under anodic polarization, localized dissolved spots presented on the as-received sample, where crevice corrosion mostly initiated from. For cooling rates 2 and 5°C/s, localized dissolved spots were also observed but crevice corrosion was mostly presented as general corrosion instead of from local spots, ascribed to enhanced tendency of uniform dissolution due to microstructure refinement and homogenization. For cooling rate 10°C/s, crevice corrosion expanded flocculently, ascribed to preferential dissolution of pearlitic nodules with entangled cementite due to over refinement. Crevice corrosion was obviously accelerated by microstructure refinement. Cooling rates 5 and 10°C/s led to the fastest and slowest expansion of the corroded area, respectively, while the corrosion depth was just the opposite based on the same amount of metal loss. This work provides important information regarding the effect of pearlitic microstructure refinement on crevice corrosion and introduces a facile method for in situ monitoring of crevice corrosion.

In situ monitoring of electrosprayed water microdroplets using laser and LED light attenuation technique: Comparison with ultra-high-speed camera imaging

2021 ◽  
Vol 129 (18) ◽  
pp. 183305
Author(s):  
Mário Janda ◽  
Mostafa E. Hassan ◽  
Viktor Martišovitš ◽  
Karol Hensel ◽  
Michal Kwiatkowski ◽  
...  
Keyword(s):  
High Speed ◽  
Light Attenuation ◽  
In Situ Monitoring ◽  
High Speed Camera ◽  
Led Light ◽  
Camera Imaging ◽  
Ultra High Speed ◽  
Technique Comparison

Uniaxial High-Speed Micro-Scale Three-Dimensional Surface Topographical Measurements Using Fringe Projection

2020 ◽  
Author(s):  
Yi Zheng ◽  
Beiwen Li
Keyword(s):  
High Speed ◽  
Sample Surface ◽  
3D Scanning ◽  
In Situ Monitoring ◽  
Fringe Projection ◽  
Depth Information ◽  
Projection Technique ◽  
Projection System ◽  
Loop Control

Abstract In-situ inspection has drawn many attentions in manufacturing due to the importance of quality assurance. Having an accurate and robust in-situ monitoring can assist corrective actions for a closed-loop control of a manufacturing process. The fringe projection technique, as a variation of the structured light technique, has demonstrated significant potential for real-time in-situ monitoring and inspection given its merits of conducting simultaneous high-speed and high accuracy measurements. However, high-speed 3D scanning methods like fringe projection technique are typically based on triangulation principle, meaning that the depth information is retrieved by analyzing the triangulation relationship between the light emitter (i.e., projector), the image receiver (i.e., camera) and the tested sample surface. Such measurement scheme cannot reconstruct 3D surfaces where large geometrical variations are present, such as a deep-hole or a stair geometry. This is because large geometrical variations will block the auxiliary light used in the triangulation based methods, which will resultantly cause a shadowed area to occur. In this paper, we propose a uniaxial fringe projection technique to address such limitation. We measured a stair model using both conventional triangulation-based fringe projection technique and the proposed method for comparison. Our experiment demonstrates that the proposed uniaxial fringe projection technique can perform high-speed 3D scanning without shadows appearing in the scene. Quantitative testing shows that an accuracy of 1.15% can be obtained using the proposed uniaxial fringe projection system.

scholarly journals Towards real-time in-situ monitoring of hot-spot defects in L-PBF: a new classification-based method for fast video-imaging data analysis

2021 ◽  
Author(s):  
Matteo Bugatti ◽  
Bianca Maria Colosimo
Keyword(s):  
Additive Manufacturing ◽  
Real Time ◽  
Process Monitoring ◽  
Defect Detection ◽  
High Speed ◽  
Data Extraction ◽  
In Situ Monitoring ◽  
Imaging Data ◽  
Computational Speed

AbstractThe increasing interest towards additive manufacturing (AM) is pushing the industry to provide new solutions to improve process stability. Monitoring is a key tool for this purpose but the typical AM fast process dynamics and the high data flow required to accurately describe the process are pushing the limits of standard statistical process monitoring (SPM) techniques. The adoption of novel smart data extraction and analysis methods are fundamental to monitor the process with the required accuracy while keeping the computational effort to a reasonable level for real-time application. In this work, a new framework for the detection of defects in metal additive manufacturing processes via in-situ high-speed cameras is presented: a new data extraction method is developed to efficiently extract only the relevant information from the regions of interest identified in the high-speed imaging data stream and to reduce the dimensionality of the anomaly detection task performed by three competitor machine learning classification methods. The defect detection performance and computational speed of this approach is carefully evaluated through computer simulations and experimental studies, and directly compared with the performance and computational speed of other existing methods applied on the same reference dataset. The results show that the proposed method is capable of quickly detecting the occurrence of defects while keeping the high computational speed that would be required to implement this new process monitoring approach for real-time defect detection.

Dynamic response of soft soils in high-speed rail foundation: in situ measurements and time domain finite element method model

2019 ◽  
Vol 56 (12) ◽  
pp. 1832-1848 ◽  
Author(s):  
Yiqun Tang ◽  
Qi Yang ◽  
Xingwei Ren ◽  
Siqi Xiao
Keyword(s):  
Dynamic Response ◽  
Time Domain ◽  
High Speed ◽  
In Situ Measurements ◽  
Vertical Acceleration ◽  
High Speed Rail ◽  
Foundation Soil ◽  
Train Speed ◽  
The Time Domain

The dynamic response of soil to vibrations induced by moving trains has been widely studied using in situ measurements. However, few in situ tests have been conducted to measure the resulting vibration of foundation soils, especially for the foundation of high-speed rail (HSR) in a soft area. In this study, a number of field experiments were conducted on Shanghai–Hangzhou HSR in a suburb of Shanghai, China. The testing instruments were installed in foundation soils just beneath the HSR track to measure the vibration induced by trains moving at different speeds. Test results show the frequencies of foundation soil vibration are characterized by the train speed and geometrical features of the trains and slab track. In the frequency domain, the dominant frequency bands for vertical acceleration, velocity, and displacement of foundation soil decrease successively. In the time domain, the magnitudes of vibration levels at different locations in a soil foundation decrease gradually with increasing distance from the track. Furthermore, higher train speed can result in higher vibration level. Based on the field conditions, a three-dimensional dynamic finite–infinite element model is developed in the time domain. It shows the model is capable of capturing the primary characteristics of train-induced vibration in the field.

Analysis for Forced Vibration Test on Proto-Type Pile Foundation in Tsip

2005 ◽  
Vol 21 (4) ◽  
pp. 267-275 ◽  
Author(s):  
Yung-Yen Ko ◽  
Huei-Chun Chu ◽  
Cheng-Hsing Chen
Keyword(s):  
Forced Vibration ◽  
Pile Foundation ◽  
High Speed ◽  
Test Method ◽  
High Speed Rail ◽  
In Situ Test ◽  
Vibration Tests ◽  
Foundation Type ◽  
Method Analysis

AbstractA series of forced vibration tests were conducted on a proto-type pile foundation which is built in the Tainan Science-Based Industrial Park and is modeled on the foundation type of Taiwan High Speed Rail. The test method, analysis procedure and results of test are briefly introduced in this paper. Besides, a finite element method by using the computer program ABAQUS is used to simulate the test. Results obtained are in good agreement with the results of in-situ test, and both are helpful for understanding the characteristics of the ground responses of the site and for identification of the soil-structure interaction of Taiwan High Speed Rail foundation system.

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