scholarly journals Three-dimensional time-varying large surface displacements in coal exploiting areas revealed through integration of SAR pixel offset measurements and mining subsidence model

2020 ◽  
Vol 240 ◽  
pp. 111663 ◽  
Author(s):  
Bingqian Chen ◽  
Zhenhong Li ◽  
Chen Yu ◽  
David Fairbairn ◽  
Jianrong Kang ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Mining Subsidence ◽  
Time Varying ◽  
Surface Displacements

scholarly journals Retrieving Three-Dimensional Large Surface Displacements in Coal Mining Areas by Combining SAR Pixel Offset Measurements with an Improved Mining Subsidence Model

2021 ◽  
Vol 13 (13) ◽  
pp. 2541
Author(s):  
Bingqian Chen ◽  
Han Mei ◽  
Zhenhong Li ◽  
Zhengshuai Wang ◽  
Yang Yu ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Surface Subsidence ◽  
Mining Subsidence ◽  
Deformation Model ◽  
Horizontal Movement ◽  
One Dimensional ◽  
Mining Areas ◽  
Surface Displacements ◽  
Vertical Subsidence ◽  
Dimensional Surface

Interferometric synthetic aperture radar (InSAR) technology can obtain one-dimensional surface displacements in the radar line of sight (LOS). In the field of mining subsidence, large 3D movements often occur at the same time, and hence InSAR derived one-dimensional LOS displacements can hardly reflect the actual surface motion in mining areas. To realize the monitoring of three-dimensional large surface displacements in mining areas, a method for monitoring three-dimensional large surface displacements in mining areas that combines SAR pixel offset tracking (OT) and an improved mining subsidence model is proposed in this article. First, a new functional relationship between surface subsidence and horizontal movement combined with the characteristics of the overburden rock stress and the deformation characteristics of the fractured rock mass in coal mining areas is established. Then, a three-dimensional surface deformation model is established based on the proposed relationship between surface subsidence and horizontal movement and the radar projection equation, and finally, the optimal parameters of the deformation model are inverted iteratively using LOS deformation results obtained by OT method to retrieve the three-dimensional large displacements of the surface. The significant advantage of the method proposed in this article is that it can accurately acquire the 3D large surface displacements using only two SAR amplitude images with the same imaging geometry. To verify the accuracy and reliability of the proposed algorithm, two scenes of high-resolution spotlight TerraSAR-X images are used in this paper to conduct a three-dimensional surface displacement monitoring experiment on a working panel in the Daliuta mining area in Shaanxi Province, China, based on the proposed method. Experimental monitoring results show that the maximum surface subsidence is approximately 4.5 m, and the maximum horizontal movements in the strike and dip directions are approximately 1.4 m and 1.2 m, respectively. Using GPS measurements to verify the monitoring results, the root mean square error (RMSE) of vertical subsidence is 6.8 cm, and the RMSE of horizontal movement is 7.1 cm. Compared with those in the original mining subsidence model, the accuracies of vertical subsidence and horizontal movement in the proposed model are increased by 28.2% and 37.5%, respectively, which proves the reliability and accuracy of the proposed method.

scholarly journals Estimation of three-dimensional crustal movements in the 2011 Tohoku-oki, Japan earthquake from TerraSAR-X intensity images

2014 ◽  
Vol 2 (12) ◽  
pp. 7383-7408
Author(s):  
W. Liu ◽  
F. Yamazaki ◽  
M. Matsuoka ◽  
T. Nonaka ◽  
T. Sasagawa
Keyword(s):  
Three Dimensional ◽  
Short Time Period ◽  
Sar Images ◽  
Crustal Movements ◽  
Surface Displacements ◽  
Time Period ◽  
Intensity Images ◽  
Short Time ◽  
The Relationship ◽  
Gps Observations

Abstract. The Tohoku-Oki earthquake on 11 March 2011 caused significant widespread crustal movements. In a previous study, we proposed a method for capturing two-dimensional (2-D) surface displacements from a pair of pre- and post-event TerraSAR-X (TSX) intensity images. However, it is difficult to detect three-dimensional (3-D) displacements from one pair of TSX images. In this study, three pairs of pre- and post-event TSX images taken on different paths were used to estimate 3-D crustal movements. The relationship between the actual 3-D displacements and the converted 2-D movements in the SAR images was derived based on the observation model of a SAR sensor. The 3-D movements were then calculated from three sets of detected 2-D movements that occurred within a short time period. Compared with GPS observations, the proposed method was found to be capable of detecting the 3-D crustal movements with sub-pixel accuracy.

Time-varying mesh stiffness calculation for gear pairs with misalignment errors in multiple degrees of freedom based on an analytical method

2021 ◽  
pp. 095440622110392
Author(s):  
Qi Wen ◽  
Qi Chen ◽  
Qungui Du ◽  
Yong Yang
Keyword(s):  
Analytical Model ◽  
Contact Line ◽  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Single Pair ◽  
Time Varying ◽  
Mesh Stiffness ◽  
Position Change ◽  
Multiple Degrees Of Freedom ◽  
Effective Contact

Misalignment errors (MEs) in multiple degrees of freedom (multi-DOFs) at the mesh position will lead to a change in the time-varying mesh stiffness (TVMS) and then affect the dynamic behaviour of gear pairs. Therefore, a new, more rapid, three-dimensional analytical model for TVMS calculation for gear pairs with three rotational and three translational MEs is established in this paper, and a new solution method based on potential energy theory is presented. In addition, the correctness of the new model is verified by the finite element method (FEM). Moreover, the effective contact line, uneven distribution of mesh force on the contact line, and mesh position change are taken into account. Finally, the TVMS under different ME conditions is calculated with the new analytical model. The results showed that the different MEs have dissimilar effects on the TVMS, and the relationship between the ME and TVMS is nonlinear. In addition, the region of single-pair and double-pair teeth in contact would also change with ME.

scholarly journals Non-Probabilistic Time-Varying Reliability-Based Analysis of Corroded Pipelines Considering the Interaction of Multiple Uncertainty Variables

Energies ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1965 ◽  
Author(s):  
Xiangqin Hou ◽  
Yihuan Wang ◽  
Peng Zhang ◽  
Guojin Qin
Keyword(s):  
Reliability Analysis ◽  
Oil And Gas ◽  
Three Dimensional ◽  
Time Varying ◽  
Reliability Model ◽  
Analysis Method ◽  
Reliability Method ◽  
Corrosion Defects ◽  
Probability Information ◽  
Safe Working

Reliability analysis of corroded pipelines is critical to the integrity and safe working of pipeline infrastructure. Aiming at less probability information is obtained for corrosion pipeline engineering, and the mechanical properties of pipeline with corrosion defects deteriorate caused by the accumulative effect of corrosion growth. Based on the quasi-static analysis method and non-probability theory, this paper presents a reliability model for assessing corroded pipelines with corrosion growth. In fact, reliability analysis of corroded pipelines needs to consider the interaction of multiple uncertainty variables. By introducing interaction theory, a mathematical model of corrosion defects considering the interaction of variables is put forward. Moreover, this paper develops a non-probabilistic time-varying reliability method for pipeline systems with multiple defects. Thus, several numerical examples are investigated to discuss the effectiveness of the proposed methodology. The results show that a two-dimensional or even three-dimensional ellipsoid model with correlation has more accurate results to evaluate corroded pipelines under the interaction of multiple corroded defects with poor information. Furthermore, a non-probabilistic time-varying reliability model is established according to the time-varying characteristics of the corroded pipeline under the influence of multiple factors. An effective complement to the theory of non-probabilistic reliability analysis of system is investigated. The analysis of the results suggests that interaction of corroded pipeline has a negligible impact on reliability. It also provides a theoretical basis for maintenance and is of great significance for risk- and reliability-informed decisions regarding buried oil and gas pipelines.

Flow field and mass transport analysis in arteries with longitudinal ridges

1976 ◽  
Vol 41 (6) ◽  
pp. 910-919 ◽  
Author(s):  
L. H. Back ◽  
D. W. Crawford ◽  
R. Barndt
Keyword(s):  
Flow Field ◽  
Three Dimensional ◽  
Shear Stresses ◽  
Time Varying ◽  
Intimal Thickening ◽  
Three Dimensional Flow ◽  
Longitudinal Vortices ◽  
Arterial Walls ◽  
Transport Analysis

Recent observations have indicated that the earliest lesions of atherosclerosis frequently take the form of longitudinal and helical ridges in arteries of man. Since longitudinal vortices are expected to be present in the troughs between the longitudinal ridges, an analysis was carried out to investigate the three-dimensional flow field and the trasport of lipoproteins and oxygen molecules to arterial walls in the presence of such vortices. The calculations revealed that local hypoxia and lipoprotein accumulation mayoccur at the ridges, leading to subsequent intimal thickening and ridge growth. Higher shear stresses, calculated in the troughs between ridges, may also partially damage the endothelium and lead to intimal thickening and subsequent merging of the ridges. Meaningful measurements are needed in vivo to determine the strength of the vortices, their time-varying behavior, and the actual transverse variations in shear stress, oxygen transport, and lipoprotein accumulation from trough to ridge regions, in order to appraise the present findings and to learn more about the observed progressive thickening and widening of ridges with increasing degrees of intimal thickening and atherosclerosis.

scholarly journals Publisher Correction to: Three-dimensional tumor growth in time-varying chemical fields: a modeling framework and theoretical study

2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Markos Antonopoulos ◽  
Dimitra Dionysiou ◽  
Georgios Stamatakos ◽  
Nikolaos Uzunoglu
Keyword(s):  
Tumor Growth ◽  
Theoretical Study ◽  
Three Dimensional ◽  
Time Varying ◽  
Modeling Framework ◽  
Chemical Fields

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