scholarly journals A Flexible and Economic Method to Improve the Ability of Electromagnetic Flanging for Tubes

2021 ◽  
Author(s):  
Qi Xiong ◽  
Zhe Li ◽  
Jianhua Tang ◽  
Hang Zhou ◽  
Meng Yang ◽  
...  
Keyword(s):  
High Speed ◽  
Rapid Development ◽  
Discharge Voltage ◽  
Forming Process ◽  
Electromagnetic Forces ◽  
Electromagnetic Structure ◽  
Economic Method ◽  
Element Simulation ◽  
Geometrical Matching ◽  
Aluminum Alloy Tube

Abstract In recent years we have seen the rapid development of electromagnetic flanging of tubes, which uses coils to generate electromagnetic forces to achieve the deformation with high speed but without contact. However, the electromagnetic force decays rapidly with the increase of distance, resulting in strict requirements of geometrical matching between the coils and the tubes. Usually, new coils should be fabricated for tubes with new sizes, which is inconvenient and uneconomical. Therefore, a more flexible and economical method is proposed in this article, which introduces a solenoid field shaper into the existing electromagnetic flanging system. By adjusting the structure and the position of the field shaper, the distribution of electromagnetic forces can be reshaped to form tubes with various sizes, without changing the coil, whose cost is much higher than a field shaper. The principle of this method is introduced in detail. Then an electromagnetic-structure coupled finite element simulation model is established to calculate the forming process. The results show that when forming an A1060-O aluminum alloy tube with an inner diameter of 110mm, the discharge voltage can be tuned down from 8.5kV, without field shaper, to 7.11kV, with field shaper. That means the energy consumption of the system can be saved by 30%, and the manufacturing process of the field shaper is simpler than that of the forming coil. What’s more, when forming tubes with different sizes, the new method shows higher effectiveness, greater flexibility, and lower cost than the traditional way.

Based on Abaqus of Simulating and Analyzing the Incremental Forming Method of Water Jet

2013 ◽  
Vol 401-403 ◽  
pp. 69-72
Author(s):  
Ling Yun Zhang ◽  
Dong Hui Li
Keyword(s):  
Experimental Data ◽  
Process Simulation ◽  
Manufacturing Industry ◽  
Incremental Forming ◽  
Rapid Development ◽  
Water Jet ◽  
Essential Factor ◽  
Forming Process ◽  
Batch Production ◽  
Element Simulation

With the rapid development and widespread use of water jet technology, the water jet forming method is also got attention by the manufacturing industry. Its advantage is no need for manufacturing the mold and forming directly, applies to small batch production. This paper is mainly study the finite element simulation of water jet forming method. The essential factor of water jet forming process simulation is to simplify the mold in reasonable mechanics method. Compared with existing experimental data to verify the accuracy of the model, and analyze the characteristics of the water jet forming.

Experimental and Numerical Analyses of Tubular Electrohydraulic Forming Process

2021 ◽  
Vol 871 ◽  
pp. 80-86
Author(s):  
Ya Nan Wei ◽  
Fei Fei Zhang ◽  
Bo Wei ◽  
Hui Xu ◽  
Kai He
Keyword(s):  
High Speed ◽  
Discharge Voltage ◽  
Forming Process ◽  
Electrohydraulic Forming ◽  
High Speed Forming ◽  
Forming Efficiency ◽  
History Of ◽  
Instantaneous Discharge ◽  
And Performance ◽  
Forming Methods

Electrohydraulic forming (EHF) is a kind of high speed forming process, which deforms the metal by shock wave through instantaneous discharge of high voltage in water. Compared with the traditional forming methods, this high speed forming process can greatly improve the formability of the materials. There are many processing factors that affect the forming efficiency and performance of the electrohydraulic forming process, one of which is the discharge voltage between the electrodes. In this paper, three electrohydraulic forming experiments with various die shapes were carried out under various discharge voltage conditions. And the bulge height and axial length of the aluminum alloy A6061 tubes under different conditions were compared. Besides, finite element numerical simulation was also performed to quantitatively investigate the deformation history of the tube.

Recent Patents on the Angular Contact Ball Bearing of High-Speed Motorized Spindle

2020 ◽  
Vol 13 ◽  
Author(s):  
Yudong Bao ◽  
Linkai Wu ◽  
Yanling Zhao ◽  
Chengyi Pan
Keyword(s):  
High Speed ◽  
Ball Bearing ◽  
Rapid Development ◽  
Ceramic Materials ◽  
Development Trend ◽  
Numerical Control ◽  
Angular Contact Ball Bearing ◽  
Practical Applications ◽  
High Speed Cutting ◽  
Advantages And Disadvantages

Background:: Angular contact ball bearings are the most popular bearing type used in the high speed spindle for machining centers, The performance of the bearing directly affects the machining efficiency of the machine tool, Obtaining a higher value is the direction of its research and development. Objective:: By analyzing the research achievements and patents of electric spindle angular contact bearings, summarizing the development trend provides a reference for the development of electric spindle bearings. Methods:: Through the analysis of the relevant technology of the electric spindle angular contact ball bearing, the advantages and disadvantages of the angular contact ball bearing are introduced, and the research results are combined with the patent analysis. Results:: With the rapid development of high-speed cutting and numerical control technology and the needs of practical applications, the spindle requires higher and higher speeds for bearings. In order to meet the requirements of use, it is necessary to improve the bearing performance by optimizing the structure size and improving the lubrication conditions. Meanwhile, reasonable processing and assembly methods will also have a beneficial effect on bearing performance. Conclusion:: With the continuous deepening of bearing technology research and the use of new structures and ceramic materials has made the bearing's limit speed repeatedly reach new highs. The future development trend of high-speed bearings for electric spindles is environmental protection, intelligence, high speed, high precision and long life.

Dynamic Performance of High-Speed Electric Multiple Unit within Multi-Body System Simulation

2019 ◽  
Vol 12 (4) ◽  
pp. 339-349
Author(s):  
Junguo Wang ◽  
Daoping Gong ◽  
Rui Sun ◽  
Yongxiang Zhao
Keyword(s):  
High Speed ◽  
Rapid Development ◽  
Dynamic Performance ◽  
Body System ◽  
High Speed Railway ◽  
Evaluation Indexes ◽  
Actual Operation ◽  
Multiple Unit ◽  
The Stability ◽  
Multi Body

Background: With the rapid development of the high-speed railway, the dynamic performance such as running stability and safety of the high-speed train is increasingly important. This paper focuses on the dynamic performance of high-speed Electric Multiple Unit (EMU), especially the dynamic characteristics of the bogie frame and car body. Various patents have been discussed in this article. Objective: To develop the Multi-Body System (MBS) model of EMU, verify whether the dynamic performance meets the actual operation requirements, and provide some useful information for dynamics and structural design of the proposed EMU. Methods: According to the technical characteristics of a typical EMU, a MBS model is established via SIMPACK, and the measured data of China high-speed railway is taken as the excitation of track random irregularity. To test the dynamic performance of the EMU, including the stability and safety, some evaluation indexes such as wheel-axle lateral forces, wheel-axle lateral vertical forces, derailment coefficients and wheel unloading rates are also calculated and analyzed in detail. Results: The MBS model of EMU has better dynamic performance especially curving performance, and some evaluation indexes of the stability and safety have also reached China’s high-speed railway standards. Conclusion: The effectiveness of the proposed MBS model is verified, and the dynamic performance of the MBS model can meet the design requirements of high-speed EMU.

scholarly journals Enhanced electrical conductivity and mechanical properties in thermally stable fine-grained copper wire

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Qingzhong Mao ◽  
Yusheng Zhang ◽  
Yazhou Guo ◽  
Yonghao Zhao
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Electrical Conductivity ◽  
Yield Strength ◽  
High Speed ◽  
Copper Wire ◽  
Rapid Development ◽  
Dislocation Slip ◽  
Ultrafine Grains ◽  
The Wire

AbstractThe rapid development of high-speed rail requires copper contact wire that simultaneously possesses excellent electrical conductivity, thermal stability and mechanical properties. Unfortunately, these are generally mutually exclusive properties. Here, we demonstrate directional optimization of microstructure and overcome the strength-conductivity tradeoff in copper wire. We use rotary swaging to prepare copper wire with a fiber texture and long ultrafine grains aligned along the wire axis. The wire exhibits a high electrical conductivity of 97% of the international annealed copper standard (IACS), a yield strength of over 450 MPa, high impact and wear resistances, and thermal stability of up to 573 K for 1 h. Subsequent annealing enhances the conductivity to 103 % of IACS while maintaining a yield strength above 380 MPa. The long grains provide a channel for free electrons, while the low-angle grain boundaries between ultrafine grains block dislocation slip and crack propagation, and lower the ability for boundary migration.

scholarly journals An Improved Lagrangian-Inverse Method for Evaluating the Dynamic Constitutive Parameters of Concrete

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1871
Author(s):  
Xinlu Yu ◽  
Yingqian Fu ◽  
Xinlong Dong ◽  
Fenghua Zhou ◽  
Jianguo Ning
Keyword(s):  
High Speed ◽  
Inverse Method ◽  
Image Correlation ◽  
Analysis Method ◽  
Stress Strain ◽  
Optical Techniques ◽  
Element Simulation ◽  
Non Linear ◽  
Constitutive Parameters ◽  
Inverse Analysis Method

The dynamic constitutive behaviors of concrete-like materials are of vital importance for structure designing under impact loading conditions. This study proposes a new method to evaluate the constitutive behaviors of ordinary concrete at high strain rates. The proposed method combines the Lagrangian-inverse analysis method with optical techniques (ultra-high-speed camera and digital image correlation techniques). The proposed method is validated against finite-element simulation. Spalling tests were conducted on concretes where optical techniques were employed to obtain the high-frequency spatial and temporal displacement data. We then obtained stress–strain curves of concrete by applying the proposed method on the results of spalling tests. The results show non-linear constitutive behaviors in these stress–strain curves. These non-linear constitutive behaviors can be possibly explained by local heterogeneity of concrete. The proposed method provides an alternative mean to access the dynamic constitutive behaviors which can help future structure designing of concrete-like materials.

The Design and Implementation of ECC High-Speed Encryption Engine Based on FPGA

2012 ◽  
Vol 459 ◽  
pp. 544-548 ◽  
Author(s):  
Wei Liang ◽  
Jian Bo Xu ◽  
Wei Hong Huang ◽  
Li Peng
Keyword(s):  
Data Transmission ◽  
High Speed ◽  
Lower Cost ◽  
Low Cost ◽  
Rapid Development ◽  
Security Technology ◽  
Multiplication Algorithm ◽  
Secure Data Transmission ◽  
And Performance ◽  
Computation Speed

Network security technology ensures secure data transmission in network. Meanwhile, it brings extra overhead of security system in terms of cost and performance, which seriously affects the rapid development of existing high-speed encryption systems. The existing encryption technology cannot meet the demand of high security, low cost and high real-time. For solving above problems, an ECC encryption engine architecture based on scalable public key cipher and a high-speed configurable multiplication algorithm are designed. The algorithm was tested on FPGA platform and the experiment results show that the system has better computation speed and lower cost overhead. By comparing with other systems, our system has benefits in terms of hardware overhead and encryption time ratio

scholarly journals Broadband Wireless Channel in Composite High-Speed Railway Scenario: Measurements, Simulation, and Analysis

2017 ◽  
Vol 2017 ◽  
pp. 1-15 ◽  
Author(s):  
Jianwen Ding ◽  
Lei Zhang ◽  
Jingya Yang ◽  
Bin Sun ◽  
Jiying Huang
Keyword(s):  
Ray Tracing ◽  
Communication Systems ◽  
High Speed ◽  
Channel Model ◽  
High Reliability ◽  
Rapid Development ◽  
Path Loss ◽  
Wireless Channel ◽  
Delay Spread ◽  
High Speed Railway

The rapid development of high-speed railway (HSR) and train-ground communications with high reliability, safety, and capacity promotes the evolution of railway dedicated mobile communication systems from Global System for Mobile Communications-Railway (GSM-R) to Long Term Evolution-Railway (LTE-R). The main challenges for LTE-R network planning are the rapidly time-varying channel and high mobility, because HSR lines consist of a variety of complex terrains, especially the composite scenarios where tunnels, cuttings, and viaducts are connected together within a short distance. Existing researches mainly focus on the path loss and delay spread for the individual HSR scenarios. In this paper, the broadband measurements are performed using a channel sounder at 950 MHz and 2150 MHz in a typical HSR composite scenario. Based on the measurements, the pivotal characteristics are analyzed for path loss exponent, power delay profile, and tap delay line model. Then, the deterministic channel model in which the 3D ray-tracing algorithm is applied in the composite scenario is presented and validated by the measurement data. Based on the ray-tracing simulations, statistical analysis of channel characteristics in delay and Doppler domain is carried out for the HSR composite scenario. The research results can be useful for radio interface design and optimization of LTE-R system.

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