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Probabilistic Fracture Mechanics Assessment of Piping Welds in A Nuclear Power Plant

Probabilistic Fracture Mechanics Assessment of Piping Welds ...

2014年海峡两岸破坏科学与材料试验学术会议暨第十二届破坏科学研讨会、第十届全国MTS材料试验学术会议

作者： R.F.Liu C.C.Huang C.C.Chen C.L.Fuang T.S.Yang Department of Nuclear Generation Taiwan Power Company Taipei Mechanical and System Engineering Program Institute of Nuclear Energy Research Taoyuan

This paper is to perform a probabilistic fracture mechanics assessment of piping welds in a nuclear power plant with considering residual stress *** assess the structural integrity objectively, the probabilistic fracture mechanics analysis code for nuclear piping is employed to estimate the leak probabilities of the *** the aging related degradation mechanism, crack growth rates in the welds subjected to fatigue and stress corrosion cracking are applied in Monte Carlo *** order to verify the influence of overlay welding on stress improvement, a series of residual stress distributions in the welds are determined using the Finite Element *** geometries, material properties and operating loads of the piping system are based on those in the piping stress *** results show that the leak probabilities increase with operating loads are significantly related to welding residual *** compressive stresses at the inner surface of original pipe, weld overlay is an efficient way to avoid crack propagation during subsequent *** addition, the leak probability distributions can be regarded as the important factors for structural safety and operational stability evaluation of the piping system.

关键词： Probabilistic fracture mechanics Weld overlay Residual stress influence

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Experimental study on spreading flame behavior over inclined electrical wire with AC electric fields 10

Experimental study on spreading flame behavior over inclined...

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10th Asia-Pacific Conference on Combustion, ASPACC 2015

作者： Lim, S.J. Kim, M.K. Park, J. Fujita, O. Chung, S.H. Interdisciplinary Program of Biomechanical Engineering Pukyong National University Busan Korea Republic of Environmental and Energy System Research Division Korea Institute of Machinery and Materials Daejeon Korea Republic of Department of Mechanical Engineering Pukyong National University Busan Korea Republic of Division of Mechanical and Science Hokkaido University Sapporo Japan Clean Combustion Research Center King Abdullah University of Science and Technology Thuwal Saudi Arabia

The effect of applied electric fields on the spreading flame over slanted Polyethylene (PE) insulated electrical wire was investigated experimentally by varying the AC frequency and voltage. The result showed that the spread rate of downwardly spreading flame decreased in increase of voltage and frequency, while that of upward flame spread rate exhibited complicated behavior with applied voltage and frequency. Downwardly spreading flame size became smaller in increase of applied voltage and frequency, while the flame leaned toward burnt side. When the flame spread upwardly, the flame size experienced large variation with applied voltage and frequency. Such flames leaned toward unburned side. Based on flame shape and the slanted direction of flame, the flame spread rate could be explained by thermal balance mechanism.

关键词： Electric fields

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Loss Balancing for Physics-Informed Neural Networks Considering Procedure for Solving Partial Differential Equations

Loss Balancing for Physics-Informed Neural Networks Consider...

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International Symposium on Soft Computing and Intelligent systems (SCIS)

作者： Manabu Kojima Kazuma Otsuki Masato Suzuki Masajiro Abe Masaaki Baba Kazuya Yokota Master's Program in Mechanical Engineering Nagaoka University of Technology Nagaoka Japan Department of System Safety Engineering Nagaoka University of Technology Nagaoka Japan Department of Mechanical Engineering Nagaoka University of Technology Nagaoka Japan

ISBN: (数字)9798350373332

ISBN: (纸本)9798350373349

With the development of machine learning, numerical analysis using neural networks has been devised. Remarkably, physics-informed neural networks (PINNs) enable physically consistent numerical analysis by introducing a loss function that conforms to relevant governing equations. Moreover, research is rapidly advancing for the application of PINNs to inverse analysis in areas such as physical property identification. For a PINN to learn governing equations, the weights of the loss functions should be properly determined because they have different roles in components such as boundary conditions, initial conditions, and governing equations. However, weight setting is generally challenging. We propose a loss balancing method considering the procedure for solving partial differential equations. The proposed method is validated through comparisons with conventional solvers.

关键词： Training Heating systems Numerical analysis Partial differential equations Neural networks Manuals Machine learning Object recognition MATLAB Convergence

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Merge LiDAR and High-precision Digital Map for Real-time Object Detection and GNSS Heading Calibration

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Journal of Institute of Control, Robotics and systems 2023年第4期29卷 301-307页

作者： Sim, Hongseok Baek, Seungbeom Lee, Jaewook Moon, Heechang Industrial Convergence Interdepartmental Program Autonomous Vehicle·Intelligent Robotics Hongik University Korea Republic of Mechanical and System Design Engineering Hongik University Korea Republic of

In this study, a method was proposed for correcting the object positioning error of light detection and ranging (LiDAR) due to the roll, pitch, and yaw data error of the inertial measurement unit sensor in the global navigation satellite system (GNSS) sensor by using a high-precision digital map. A real-time obstacle map was formed using Velodyne’s three-dimensional lines, VLP-32 and VLP-16. The high-precision digital map was then merged into the LiDAR map. The map obtained by combining LiDAR and high-precision digital maps did not match because of certain errors. To eliminate these errors, a method of fitting a map with high precision on the XY plane was established, and fittable criteria were determined. Algorithm verification was performed during actual driving, and errors were removed in real time. Various autonomous driving technologies can be developed using the sensor error data preprocessing process. Copyright© ICROS 2023.

关键词： Errors

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Recognition of Real-time Traffic Signals Using the Algorithm Fusion of On-board Graphic Chip-based Machine Learning and Deep Learning

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Journal of Institute of Control, Robotics and systems 2022年第2期28卷 88-94页

作者： Lee, Jaewook Baek, Seungbeom Choi, Eunji Moon, Heechang Industrial Convergence Interdepartmental Program Autonomous Vehicle·Intelligent Robotics Hongik University Korea Republic of Mechanical and System Design Engineering Hongik University Korea Republic of

The recognition of traffic light in unmanned autonomous driving is one of the key functions. In general, to achieve this goal, deep learning and image processing technology are mainly used in autonomous driving industry. Both technologies have high recognition rates alone, but misrecognition can occur because of interference of the environment. misrecognitions are considered important problem because it may lead to big accidents. In this paper, we suggest using machine learning based on LabVIEW and deep running grounded in Python to increase recognition rate at intersection. By using both technologies, we can minimize the impact of the environment on traffic light recognition and reduce misrecognition. © ICROS 2022.

关键词： Image processing

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An ergonomic study for 6s workplace improvement

An ergonomic study for 6s workplace improvement

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IIE Annual Conference and Expo 2014

作者： Aqlan, Faisal Lam, Sarah S. Ramakrishnan, Sreekanth Testani, Michael Industrial and System Engineering Program Department of Mechanical Civil and Environmental Engineering University of New Haven West HavenCT06516 United States Department of Systems Science and Industrial Engineering State University of New York at Binghamton BinghamtonNY13902 United States IBM Corporation WalthamMA02451 United States IBM Corporation EndicottNY13760 United States

ISBN: (纸本)9780983762430

This paper presents a workplace ergonomic study in a high-end server manufacturing environment to assess ergonomics risks and enhance the Lean transformation. Operators perform heavy and repetitive lifting and movement of products could place stress on their back and upper extremities. Forceful exertions to move a manual forklift in the workplace area could lead to fatigue and possible damage to muscles and other tissues. The objective of this study is to reduce ergonomics risks to an acceptable level and provide operators with the right tools and proper work environment. Digital human modeling based on the Jack software, is used for risk assessment. Results are analyzed to provide proper solutions. Ergonomic risks assessed include: force and posture risks, noise, vibration, temperature, and illumination. Lean process is implemented in the workplace to reduce the Lean wastes that include waiting time, transportation, and non-value-add processes. Ergonomic improvements are introduced to complement and support the Lean process implementation. Three main ergonomic risks are found to be high and could affect the operators: energy expenditure, posture, and back force. Several modifications are implemented to reduce these risks: the manual forklift is replaced with an automated forklift that is easy to move and requires less human effort, the workplace area is expanded to provide more work space, and the operators are provided with proper tools to perform the task without risk.

关键词： Manufacture

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Integrating lean and ergonomics to improve internal transportation in a manufacturing environment

Integrating lean and ergonomics to improve internal transpor...

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IIE Annual Conference and Expo 2014

作者： Aqlan, Faisal Lam, Sarah S. Ramakrishnan, Sreekanth Boldrin, Warren Industrial and System Engineering Program Department of Mechanical Civil and Environmental Engineering University of New Haven West HavenCT06516 United States Department Systems Science and Industrial Engineering State University of New York at Binghamton BinghamtonNY13902 United States IBM Corporation WalthamMA02451 United States IBM Corporation PoughkeepsieNY12601 United States

ISBN: (纸本)9780983762430

This paper presents a study that integrates lean manufacturing and ergonomic principles to redesign and improve the internal transportation process in a high-end server manufacturing environment. Transportation of electronic parts within the factories is an important issue. The current transportation carts present quality hazards to electronic parts and they were not designed to handle the right dimensions and quantities of the newly introduced products. Furthermore, the current flow of carts introduces waiting time for the carts in the assembly areas. Inefficient transportation not only increases the waiting times but also the transportation costs. The objective of this study is to improve the transportation process and redesign transportation carts that are currently used to transport parts between different areas in a high-end server manufacturing environment utilizing lean and ergonomic principles. A new lean-based flow of transportation carts is proposed to reduce the waiting time and transported distance by having separate carts for each area. The new design of the carts represents a Poke-Yoke that prevents the operators from stacking the cards. Ergonomic principles are also considered in the new design. The number of carts required is estimated based on historical demand, outcomes from containment actions, current processes, and inputs from the production-planning department. The new lean-based flow and design of carts have resulted in cost savings and cost avoidance.

关键词： Lean production

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Modeling and control of a novel tilt — Roll rotor quadrotor UAV

Modeling and control of a novel tilt — Roll rotor quadrotor...

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International Conference on Unmanned Aircraft systems (ICUAS)

作者： Fatih Şenkul Erdinç Altuğ System Dynamics and Control Graduate Program İstanbul Technical University Istanbul Turkey Department of Mechanical Engineering İstanbul Technical University Istanbul Turkey

The use of unmanned aerial vehicles (UAVs) for military, scientific, and civilian sectors are increasing drastically in recent years. The quadrotor platform has been used for many applications and research studies, as well. One of the limiting factors that prevents further implementation of the quadrotor system into applications, is the way quadrotor moves. It needs to tilt along the desired direction of motion. By doing this it can have necessary acceleration towards that direction. But tilting has the undesired effect of moving the onboard cameras' direction of view. This becomes an issue for surveillance and other vision based tasks. This study presents the design and control of a novel quadrotor system. Unlike previous study that uses regular quadrotor, this study proposes an alternative propulsion system formed by tilting rotors. This design eliminates the need of tilting the airframe, and it suggests superior performance with respect to regular quadrotor design. The mathematical model of the tiltable-rotor type quadrotor and designed control algorithms are explained. Various simulations are developed on MATLAB, in which the proposed quadrotor aerial vehicle has been successfully controlled. Comparison of the proposed system to regular quadrotor suggests better performance.

关键词： Rotors Aircraft Atmospheric modeling Acceleration Vehicles Mathematical model Equations

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Design of a flapping-wing aerial vehicle based on four-bar mechanism

Design of a flapping-wing aerial vehicle based on four-bar m...

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International Conference on Unmanned Aircraft systems (ICUAS)

作者： Abdurrahman İşbitirici Erdinç Altuğ System Dynamics and Control Graduate Program Ístanbul Technical University Istanbul Turkey Department of Mechanical Engineering Ístanbul Technical University Istanbul Turkey

Speed, agility, maneuverability, range and efficiency of birds and insects are far beyond the conventional flying mini vehicles. There are various research works to create vehicles that imitate these amazing creatures. In this paper, a wing mechanism is designed for a micro aerial vehicle using four flapping wings. In this system, a four-bar mechanism is preferred as the wing mechanism. In order to obtain flapping motion from rotation of the motor, a crank rocker mechanism is used by connecting the shortest link to the fixed link. Flapping range (swing angle) is determined by obtaining dead-center positions. It is chosen as large as possible since it is related to the lift force. Optimization of transmission angle is made in order to transmit torque from the input link to the output link with a minimum loss. The link length ratio is computed by deciding swing angle and angle between dead center positions. While computing the ratio of lengths of the links, deviation of transmission angle from 90° is attempted to be adjusted to a minimum level. The dimensions of the wings are determined with respect to the lift force. The prototype vehicle has been designed and manufactured with the obtained results.

关键词： Mathematical model Torque Force Acceleration Vehicles Couplers Joining processes

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Vision-based servo control of a quadrotor air vehicle

Vision-based servo control of a quadrotor air vehicle

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IEEE International Symposium on Computational Intelligence in Robotics and Automation (CIRA)

作者： Zehra Ceren Erdinç Altuğ System dynamics and control graduate program İstanbul Technical University Istanbul Turkey Mechanical Engineering Department İstanbul Technical University Istanbul Turkey

ISBN: (纸本)9781424448081

Unmanned aerial vehicles (UAVs) are seeing more widespread use in military, scientific, and civilian sectors in recent years. This study presents algorithms for the visual-servo control of an UAV. The helicopter has been stabilized with visual information through the control loop. Unlike previous study that use pose estimation approach which is time consuming and subject to various errors, the visual-servo control is more reliable and fast. The model involves the camera speed and visual sensor blocks. Visual sensor block consists of the camera model and feature extraction blocks. Various simulations are developed on MATLAB, in which the quadrotor aerial vehicle has been visual-servo controlled. In order to show the effectiveness of the algorithms, experiments were performed on a model UAV which suggest successful performance.

关键词： Servosystems Helicopters Unmanned aerial vehicles Cameras Open loop systems Feature extraction Error correction Mathematical model Robot vision systems Aircraft navigation

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