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Short-term creep behavior in P91 heat-resistant steel at low stress

Short-term creep behavior in P91 heat-resistant steel at low...

Chinese Materials Congress on Methods of design and Characterization of Materials, Research and Development of Technological Processes, 2015

作者： Zhao, Pengshuo Shen, Junjie Zhang, Hui Tianjin key Laboratory of the Design and Intelligent Control of the Advanced Mechatronical System School of Mechanical Engineering Tianjin University of Technology 391 Binshui Road Xiqing District Tianjin China Tianjin Entry-Exit Inspection and Quarantine Bureau China

ISBN: (纸本)9783038357629

P91 heat-resistant steel is widely used in the high temperature of piping components of thermal power plants and nuclear power plants. In these conditions, the typical failure of P91 is mainly caused by creep at low stress. In this investigation the short-term creep behavior in P91 at low stress was investigated by helicoid spring creep test due to its high strain-sensitivity. The helicoid spring creep was based on the assumption of pure torsion. The mechanics field was firstly studied by ANSYS finite-element simulation to find the establishing conditions of pure torsion. Secondly, the creep properties of P91 were studied under the conditions of the temperatures of 0.38Tmm and the stresses of 14.6 MPa, 25 MPa, 34 MPa, respectively. The ANSYS finite-element simulation shows that the creep deformation is considered to be pure torsion when the pitch spacing of coil is between 2mm to 4mm. The creep curves show "Normal type ", and "the stress exponent" is n=0.9. © 2016 Trans Tech Publications, Switzerland.

关键词： Creep

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Two methods of determining target orientation by robot visual principle

Two methods of determining target orientation by robot visua...

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作者： Liu, Gang School of Mechanical Engineering Tianjin University of Technology Tianjin Key Laboratory of Advanced Mechanical and Electrical System Design and Intelligent Control Tianjin300384 China

ISBN: (纸本)9781538636749

By analyzing the imaging principle of the fish-eye lens in the robot vision, two methods of determination of the target orientation based on the fish-eye lens are summarized. One method uses the distortion correction to determine the target orientation, and the other uses the relationship between the target in the actual orientation and its correspondence in the imaging coordinates to determine the target orientation, both methods all use image processing technology, fast and efficiently determine the orientation of the target in the fish eye image. In this paper, the theoretical basis and experimental process of the two methods are introduced respectively. By comparing the data after the experiment, the more accurate method is analyzed and applied to the target azimuth determination of the fish-eye lens. © 2017 IEEE.

关键词： Fish-eye lens Image processing Robot vision Target orientation

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design of dual-frequency bioreactor control system

Design of dual-frequency bioreactor control system

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IEEE International Conference on Mechatronics and Automation

作者： Hongbiao Xiang Shoujun Wang Chunqiu Zhang Xingfei Li Jun Liu Tianjin Key Laboratory of the Design and Intelligent Control of the Advanced Mechatronical System Tianjin University of Technology Tianjin CN Tianjin Key Laboratory of the Design and Intelligent Control of the Advanced Mechatronical System Tianjin University Tianjin Tianjin CN

According to tissue engineering and basic principle of bionic, the low-frequency high-amplitude loading on articular cartilage is to simulate human walking or other activities, and the high-frequency low-amplitude loading is to maintain the cartilage framework structure from muscles, ligaments and other tissue. In order to build appropriate mechanical environment for cartilage tissue engineering, this paper design a dual-frequency bioreactor, and the control precision and performance is improved by a method of friction compensation. The control system is full closed loop composed of liner motor and grating scale, based on PC+PMAC opened control platform. Firstly, a dynamic equation of an open servo system is given and the friction characteristics are described based on Stribeck model. Secondly, Considering the parameters of friction model changed with the system, the controller of adaptive sliding friction compensation is designed by backstepping method, and the corresponding adaptive laws and switching functions are given. Besides, this method give analysis of its global asymptotic stability, proved by Lyapunov theorem. Finally, the adaptive sliding friction compensation control strategy is realized by Programmable Multi-Axis controller (PMAC), and the effectiveness of the method is verified by experiments. Results show that the steady state error of sinusoidal motion is decreased from the ± 22μm to ± 4μm compared with the velocity and acceleration forward feed-compensation. The dual-frequency bioreactor can simulate the mechanical environment of artificial cartilage tissue engineering on micrometer level, furthermore, it laid a foundation for the research of mechanobiology of cartilage.

关键词： Friction Mathematical model Tissue engineering Loading Adaptation models Servomotors

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Study on Rotating Speed control of Dissimilar Metal Friction Stir Welding based on Fuzzy PID 6

Study on Rotating Speed Control of Dissimilar Metal Friction...

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2021 6th International Conference on Applied Mechanics and Structural Materials, AMSM 2021

作者： Liu, Yongning Qiao, Zhifeng Liu, Qingjian Huang, Jiahao Fu, Kang Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin300384 China China

The demand for lightweight vehicles that achieve energy conservation and emission reduction continues to grow. Aluminum alloys were commonly applied to the automotive industry to reduce the structural quality of the entire vehicle. However, the cost of aluminum alloy was higher than that of steel, so the industry considered the use of aluminum in combination with low-cost materials such as steel. Traditional welding technology was limited by the great physical difference between aluminum alloy and steel. Friction Stir Welding, a solid phase welding technology, can overcome the connection problem of aluminum and its alloys with steel, but the process parameters of FSW directly affect the welding quality. This paper established the FSW process of two different metals of DC05 and AL6061. Aimed to get a good welding joint, the error of tool speed is reduced by fuzzy PID system established in this paper, and the tool speed is controlled stably. Simulink simulation was established, and compared with the simulation results, fuzzy PID control can control the precision and stability of the tool speed of FSW, improve the welding quality, and provide a certain theoretical basis for the tool speed control. © 2022 Institute of Physics Publishing. All rights reserved.

关键词： Friction stir welding

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Compensation of friction and elastic deformation for ball screw drive system

Compensation of friction and elastic deformation for ball sc...

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IEEE International Conference on Mechatronics and Automation

Nonlinear friction and elastic deformation seriously affect both static and dynamic performance of mechanical serve system, especially in the high-speed and high-precision systems. This paper focuses on modeling, identification, and compensation of non-linear friction and elastic deformation for ball screw drive system. Firstly, the parameters of the stribeck model are identified by the method of extended kalman filter. And then the parameters of stiffness model of the ball screw are identified by the method of the least square based on force analysis of system. Finally, the feed-forward compensation of friction and elastic deformation is performed. The experimental results show that: after the compensation, the steady state error of low-speed motion decreases from 42μm to ±3μm, and that of high-speed motion decreases from 95μm to ±5μm. Therefore, the method proposed can effectively compensate the disturbance of friction and elastic deformation, and improve the tracking accuracy of the ball screw drive system.

关键词： Friction Fasteners Mathematical model Servomotors Deformable models Tracking Force

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Influence of vibration on mechanical polishing micro-structured surface using discrete element method

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International Journal of Machining and Machinability of Materials 2020年第1期22卷 24-46页

作者： Wang, Guilian Lv, Bingrui Liu, Li Liu, Bin Zhou, Haibo Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin300384 China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology Tianjin300384 China Tianjin Laboratory of Control Theory and Applications in Complicated System Tianjin300384 China School of Electrical and Electronic Engineering Tianjin University of Technology Tianjin300384 China

A model using discrete element method (DEM) was conducted to simulate vibration assisted mechanical polishing micro-structured surface process by particle flow code in three dimensions (PFC3D). The effect laws of vibration frequency and amplitude on abrasive grains and polishing force were researched in detail according to the simulation results. The effects of vibration on the particles average motion velocity in one fluid cell were researched, and the simulation results show that average velocity increases with increase of vibration frequency and amplitude on the whole. The effects of vibration on the unbalanced force acting on the workpiece surface were quantified at first. The changes of average unbalanced force obviously increase for low feed rate with increase of frequency and increase approximately linearly with increase of amplitude. It is concluded that vibration with high frequency and great amplitude can significantly increase machining efficiency and improve surface quality in micro-structured surface polishing. Copyright © 2019 Inderscience Enterprises Ltd.

关键词： Finite difference method

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Wireless power transmission system with CC and CV output based on hybrid LCC-S/P topology 5

Wireless power transmission system with CC and CV output bas...

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5th International Conference on Electronics and Communication, Network and Computer Technology, ECNCT 2023

作者： Li, Kun Gong, Zheng Meng, Jiaheng Liu, Qing Tianjin University of Technology Tianjin Key Laboratory of Film Electronic and Communication Device Tianjin China Tianjin University of Technology Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control Tianjin China

ISBN: (纸本)9798350328660

Wireless Power Transfer (WPT) technology provides a convenient and efficient power supply solution for mobile devices. The utilization of constant current (CC) and constant voltage (CV) control in WPT systems proves valuable for charging battery applications. This paper presents a novel WPT system with CC and CV output characteristics, employing a switching topology. Specifically, the LCC-S and LCC-P topologies are applied and rigorously simulated. The proposed MCR-WPT system's output characteristics in both CC and CV modes are meticulously validated using Saber software. The simulation results distinctly demonstrate the system's capability to achieve CC and CV outputs within a varying load resistance range of 5Ω to 30Ω, thus conclusively establishing the efficacy of the topology switching technology. © 2023 IEEE.

关键词： Topology

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intelligent Diagnosis of Planetary Gearboxes based on DAE-CNN 14

Intelligent Diagnosis of Planetary Gearboxes based on DAE-CN...

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14th IEEE Global Reliability and Prognostics and Health Management Conference, PHM-Hangzhou 2023

作者： Kang, Tianbo Zhang, Mian Xie, Ruitong Chen, Jiwei Xiang, Hongbiao Wang, Yuhang Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin300384 China Tianjin300384 China

ISBN: (纸本)9798350301359

Planetary gearboxes (PGs) are the core transmission components of complex rotating machinery. The diverse forms of internal gear faults often complicate diagnosis and maintenance work. To improve the fault diagnosis accuracy of PGs, this paper proposes a method for diagnosing PG faults based on deep autoencoders (DAE) and convolutional neural networks (CNN). The method fully utilizes the deep learning capability of DAE and combines it with the precise recognition ability of CNN for fault features. Through precise learning in the encoding layer, it achieves deep dimensionality reduction of fault features and further learns these features after dimensionality reduction by CNN. Compared to traditional CNN, the method reduces the computation parameters and resource consumption, resulting in higher precision intelligent fault diagnosis. Experimental results demonstrate that DAE-CNN exhibits stronger fault diagnosis ability than traditional networks. © 2023 IEEE.

关键词： component DAE-CNN deep learning fault diagnosis planetary gearboxes

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Experimental Study On The Identification Model Of Dynamic Milling Force Coefficient

Experimental Study On The Identification Model Of Dynamic Mi...

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2016 4th International Conference on Machinery,Materials and Computing Technology(ICMMCT 2016)

作者： Xinghua Niu Tianding Wang Tiemin Zhao Qianyou Huang Tianjin University of Technology Tianjin Key Laboratory of the Design and Intelligent Control of the Advanced Mechatronical System

The identification model of milling force coefficient is established using the model of dynamic milling force and the regression analysis of the milling force experiment data. On the basis of the existing milling force model, by simplifying and calculation, it can get the relational expression between milling force coefficient and average value of the milling force. Arranging the milling force experiment and measuring average milling force, the experiment results of milling force coefficient can be calculated. Then, the polynomial expression of identification model of milling force coefficient is established, and its coefficient values can be got by regression analysis. Finally, the accuracy and applicability of the identification model is verified by experiment. The experimental results show that the prediction results of the model are accurate and reliable, and can meet different processing conditions, provide the theoretical basis and reference for the further study of milling process and optimization.

关键词： milling force model coefficient identification orthogonal experiment regression analysis

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Mechanical Properties of Glycated Cracked Articular Cartilage Under Uniaxial and Cyclic Tensile Loading

SSRN

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SSRN 2025年

作者： Gao, Li-Lan Fang, Yi Lin, Xiang-Long Kong, De-Zhao Tan, Yan-Song Li, Rui-Xin Sun, Kai Zhang, Chun-Qiu Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin300382 China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology Tianjin300382 China Co. Ltd. Tianjin300190 China Tianjin Key Laboratory of Oral and Maxillofacial Function Reconstruction Tianjin Stomatological Hospital The Affiliated Stomatological Hospital of Nankai University Tianjin300041 China Orthopaedic of Tianjin First Central Hospital Tianjin300190 China

In clinical diagnosis, diabetes, and arthritis were often considered independent, which leads to diabetics getting worse by ignoring early arthritis symptoms. Therefore, the fatigue damage mechanism of articular cartilage in a hyperglycemic environment must be clarified. Under simulating physiological loads, this study delved into glycated cracked cartilage's fracture toughness and damage mechanism. Moreover, by introducing the glucose concentration as a crucial variable, a constitutive model of the ratcheting behavior of glycated cracked cartilage was established, which is utilized to predict the impacts of glycation on cartilage. The findings of this study revealed that the glycation environment causes cartilage hardening, which, in turn, leads to a substantial 38.1% reduction in the initial strain required for crack extension, despite an enhancement in tensile strength. The study of dynamic mechanical behavior further supported this observation. Scanning electron microscopy (SEM) showed that this mechanistic change occurs after collagen fibers harden and adhere to one another in the glycation environment. Overall, these results hold significant implications for understanding osteoarthritis (OA) in diabetic patients and for developing and protecting strategies related to this condition. © 2025, The Authors. All rights reserved.

关键词： Fracture toughness

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