Fatigue Analysis of Driving Based on Detection of Three-Dimensional Center of Gravity Using Depth Camera

2020 ◽  
Vol 2020.29 (0) ◽  
pp. 2014
Author(s):  
Takayuki NISHIGAME ◽  
Yutaka WATANABE
Keyword(s):  
Three Dimensional ◽  
Fatigue Analysis ◽  
Center Of Gravity ◽  
Depth Camera

scholarly journals Comparison of Depth Camera and Terrestrial Laser Scanner in Monitoring Structural Deflections

Sensors ◽  
2020 ◽  
Vol 21 (1) ◽  
pp. 201
Author(s):  
Michael Bekele Maru ◽  
Donghwan Lee ◽  
Kassahun Demissie Tola ◽  
Seunghee Park
Keyword(s):  
Optical Sensors ◽  
Point Cloud ◽  
Three Dimensional ◽  
Laser Scanner ◽  
Point Clouds ◽  
Depth Camera ◽  
Terrestrial Laser Scanner ◽  
Cloud Data ◽  
3D Point Clouds ◽  
3D Information

Modeling a structure in the virtual world using three-dimensional (3D) information enhances our understanding, while also aiding in the visualization, of how a structure reacts to any disturbance. Generally, 3D point clouds are used for determining structural behavioral changes. Light detection and ranging (LiDAR) is one of the crucial ways by which a 3D point cloud dataset can be generated. Additionally, 3D cameras are commonly used to develop a point cloud containing many points on the external surface of an object around it. The main objective of this study was to compare the performance of optical sensors, namely a depth camera (DC) and terrestrial laser scanner (TLS) in estimating structural deflection. We also utilized bilateral filtering techniques, which are commonly used in image processing, on the point cloud data for enhancing their accuracy and increasing the application prospects of these sensors in structure health monitoring. The results from these sensors were validated by comparing them with the outputs from a linear variable differential transformer sensor, which was mounted on the beam during an indoor experiment. The results showed that the datasets obtained from both the sensors were acceptable for nominal deflections of 3 mm and above because the error range was less than ±10%. However, the result obtained from the TLS were better than those obtained from the DC.

Three Dimensional Grillage Analysis of Reactions on Supports of a Pre-Erection Block

2013 ◽  
Author(s):  
Sungchan Kim ◽  
Cheolho Ryu ◽  
Youngho Kim ◽  
Changbong Han ◽  
Dong Geun Kim
Keyword(s):  
Load Distribution ◽  
Three Dimensional ◽  
Evaluation Process ◽  
Center Of Gravity ◽  
Integrated System ◽  
Structural Safety ◽  
Detail Design ◽  
Grillage Analysis ◽  
Cad Models ◽  
Reaction Forces

There are many PE(Pre-Erection) Blocks in open areas of the shipyard, which are supported by the wooden, concrete, or steel supports. Their position and numbers are decided on a basis of the workers’ experiences. Recently, many shipyards have been making PE blocks with various shape and weight distribution because of the variety of kinds of ships and their building technology. Seriously, they are treating blocks which have not been experienced. In order to evaluate the reliability of all support plans of PE Blocks in such situation, many man hours (MH) are consumed, and the special knowledge and technology about structural analysis are required. We proposed how to conveniently and quickly evaluate the structural safety on PE block supports and developed an application system to implement the evaluation process with three dimensional part models of the PE block and their weight information. The evaluation is based on the simplification to a grillage model of a PE block and its grillage analysis. The load distribution on the grillage model is calculated by two approaches. The first is that the load distribution on the grillage nodes are estimated with the real weight and the center of gravity of each part of a PE block, which can be provided from design databases of the shipyard. The other is that the load distribution is optimally estimated only with the weight and the center of gravity of sub blocks of a PE block. The latter is useful in the case that block information of mother ships can be obtained without the detail design of the PE block. The integrated system has been comprehensively implemented in order to make the grillage model from the three dimensional CAD models of the PE block and their weight information, and to perform the grillage analysis for the reaction forces on the block supports. In the application program, the grillage model can be automatically built from CAD models of PE block. Also the grillage can be modified by inserting, splitting, and deleting a beam element.

A Three-Dimensional Fe Approach for the Fatigue Analysis of Tensile Armors Inside End Fittings

2021 ◽  
Author(s):  
Marcelo Miyazaki ◽  
Jose Renato De Sousa ◽  
Gilberto Bruno Ellwanger ◽  
Vinicius Ribeiro Machado da Silva
Keyword(s):  
Three Dimensional ◽  
Fatigue Analysis

scholarly journals Calibration of the Relative Orientation between Multiple Depth Cameras Based on a Three-Dimensional Target

Sensors ◽  
2019 ◽  
Vol 19 (13) ◽  
pp. 3008 ◽  
Author(s):  
Zhe Liu ◽  
Zhaozong Meng ◽  
Nan Gao ◽  
Zonghua Zhang
Keyword(s):  
Coordinate System ◽  
Camera Calibration ◽  
Three Dimensional ◽  
Field Of View ◽  
Depth Information ◽  
Depth Camera ◽  
Depth Cameras ◽  
Calibration Methods ◽  
3D Shape Reconstruction ◽  
Single Coordinate

Depth cameras play a vital role in three-dimensional (3D) shape reconstruction, machine vision, augmented/virtual reality and other visual information-related fields. However, a single depth camera cannot obtain complete information about an object by itself due to the limitation of the camera’s field of view. Multiple depth cameras can solve this problem by acquiring depth information from different viewpoints. In order to do so, they need to be calibrated to be able to accurately obtain the complete 3D information. However, traditional chessboard-based planar targets are not well suited for calibrating the relative orientations between multiple depth cameras, because the coordinates of different depth cameras need to be unified into a single coordinate system, and the multiple camera systems with a specific angle have a very small overlapping field of view. In this paper, we propose a 3D target-based multiple depth camera calibration method. Each plane of the 3D target is used to calibrate an independent depth camera. All planes of the 3D target are unified into a single coordinate system, which means the feature points on the calibration plane are also in one unified coordinate system. Using this 3D target, multiple depth cameras can be calibrated simultaneously. In this paper, a method of precise calibration using lidar is proposed. This method is not only applicable to the 3D target designed for the purposes of this paper, but it can also be applied to all 3D calibration objects consisting of planar chessboards. This method can significantly reduce the calibration error compared with traditional camera calibration methods. In addition, in order to reduce the influence of the infrared transmitter of the depth camera and improve its calibration accuracy, the calibration process of the depth camera is optimized. A series of calibration experiments were carried out, and the experimental results demonstrated the reliability and effectiveness of the proposed method.

Thermal Stress and Fatigue Analysis in Turbine Rotors

1971 ◽  
Vol 93 (1) ◽  
pp. 13-20
Author(s):  
C. L. Chow
Keyword(s):  
Thermal Stress ◽  
Steam Turbine ◽  
Three Dimensional ◽  
Cold Start ◽  
Fatigue Analysis ◽  
Stress Conditions ◽  
Computer Technique ◽  
Detailed Method ◽  
Physical Geometry ◽  
Block Relaxation

A method of thermal stress and fatigue analysis under triaxial stress conditions is presented. A rotor of a marine steam turbine is taken as a typical example to illustrate the detailed method of analysis in assessing the cycle damage life of the rotor. A computer technique of iterative block relaxation is devised for the thermal stress calculation as the physical geometry of the problem under consideration is fairly complex. This technique is particularly advantageous for such a system as (a) damping the magnitude of the oscillation in the solution of the ill-conditioned stress equations and (b) keeping the number of nodal points required in a converging solution to a minimum. Three different operating procedures of starting and loading the marine turbine have been studied with full three-dimensional stress and fatigue considerations. One of the three procedures which is found to be more desirable is recommended with the descriptions of detailed steam history and main features of the cold start throughout its whole operation.

A Three-Dimensional FE Approach for the Fatigue Analysis of Flexible Pipes Tensile Armors Inside End Fittings

2020 ◽  
Author(s):  
Marcelo N. R. Miyazaki ◽  
José Renato M. de Sousa ◽  
Gilberto B. Ellwanger ◽  
Vinicius R. da Silva
Keyword(s):  
Fatigue Resistance ◽  
Three Dimensional ◽  
Local Stress ◽  
Fatigue Analysis ◽  
Acceptance Test ◽  
Stress Concentrations ◽  
Flexible Pipes ◽  
Dimensional Finite Element ◽  
Operational Tests ◽  
Three Dimensional Finite Element

Abstract During the end fitting (EF) assembly, the tensile armors of flexible pipes are folded and then unfolded to allow the assessment to the inner sheath and the activation of the inner sealing system. This procedure leaves residual stresses and plastic deformations on these armors, which affect their fatigue resistance and, consequently, the overall performance of the pipe. Hence, in this work, a methodology to predict the fatigue resistance of tensile armors inside an EF is proposed. This methodology relies on stresses calculated with a previously presented three-dimensional finite element (FE) approach and is employed to analyze the fatigue response of a 6” production riser in catenary configuration. This fatigue analysis not only addresses the effects from several irregular sea states but also the local stress concentrations associated with the EF assembly and pre-operational tests (e. g., Factory Acceptance Test, FAT). The results obtained indicate that the EF entrance may be a critical point for fatigue failure and, moreover, the lower fatigue resistance is related to a region where higher alternate stresses occur despite the very high mean stresses are observed in other regions along the tensile armors.

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