Warm hydroforming of magnesium alloy tube with large expansion ratio within non-uniform temperature field

2012 ◽  
Vol 22 ◽  
pp. s408-s415 ◽  
Author(s):  
Gang LIU ◽  
Wen-da ZHANG ◽  
Zhu-bin HE ◽  
Shi-jian YUAN ◽  
Zhe LIN
Keyword(s):  
Temperature Field ◽  
Magnesium Alloy ◽  
Expansion Ratio ◽  
Uniform Temperature ◽  
Alloy Tube ◽  
Large Expansion ◽  
Uniform Temperature Field ◽  
Warm Hydroforming

Warm hydroforming of magnesium alloy tube with large expansion ratio

2010 ◽  
Vol 20 (11) ◽  
pp. 2071-2075 ◽  
Author(s):  
Gang LIU ◽  
Ze-jun TANG ◽  
Zhu-bin HE ◽  
Shi-jian YUAN
Keyword(s):  
Magnesium Alloy ◽  
Expansion Ratio ◽  
Alloy Tube ◽  
Large Expansion ◽  
Warm Hydroforming

Progress on High Pressure Pneumatic Forming and Warm Hydroforming of Titanium and Magnesium Alloy Tubular Components

2014 ◽  
Vol 783-786 ◽  
pp. 2456-2461 ◽  
Author(s):  
Gang Liu ◽  
Yong Wu ◽  
Jian Long Wang ◽  
Wen Da Zhang
Keyword(s):  
High Pressure ◽  
Temperature Field ◽  
Magnesium Alloy ◽  
Thickness Distribution ◽  
Expansion Ratio ◽  
Mg Alloy ◽  
Ti Alloy ◽  
Warm Hydroforming ◽  
Corner Filling ◽  
Tubular Components

Complex structural tubular components of Titanium and Magnesium alloy can be obtained at a certain temperature by high pressure pneumatic forming (HPPF) with gas medium or warm hydroforming with pressurized liquid medium. At 800°C, through experimental research on HPPF of TA18 Ti-alloy tube with expansion ratio of 50%, the influence of axial feeding on thickness distribution of the workpiece was studied. Using reasonable loading curve, the component with large ratio can be formed with a small thinning ratio as 13% with total axial feeding amount of 40mm. At 850°C, HPPF experiments of TA18 Ti-alloy component with square section were carried out. The influence of gas pressure on thickness distribution and corner filling process were analyzed. The larger the pressure, the sooner the displacement changes at the corner, and the shorter corner filling term. At pressure of 30 MPa, small corner with the relative corner radius of 2.0 can be obtained within 168s. For Mg-alloy tubular part, warm hydroforming with non-uniform temperature field was studied. By using reasonable axial temperature field and loading path, the maximum thinning ratio of Mg-alloy tubular component with expansion ratio of 35% was reduced from 21.6% to 11.6%.

Simulation and Experiment on Warm Hydroforming of AZ31 Magnesium Alloy Tube

2013 ◽  
Author(s):  
Shijian Yuan ◽  
Zejun Tang ◽  
Gang Liu
Keyword(s):  
Magnesium Alloy ◽  
Internal Pressure ◽  
Axial Direction ◽  
Sine Wave ◽  
Expansion Ratio ◽  
State Graph ◽  
Alloy Tube ◽  
Different Temperatures ◽  
Simulation And Experiment ◽  
Warm Hydroforming

The wrinkling behavior of an AZ31B magnesium alloy tube was investigated by simulation at different loading paths and at different temperatures. The effects of strain rate, internal pressure and temperature on the wrinkles were studied. Stressstrain track was analyzed in the quasi-static strain state graph of the plane stress processing to explain the changing of the wrinkles’ shape, radius and wall thickness. It is shown that shape of the wrinkles wave along the axial direction keeps the sine wave character. The radius and thinning at the top zone of the wrinkles and the width of the wrinkles increased with the temperature, the internal pressure or the axial feeding. Moreover, hydro-formability of wrinkled parts was investigated and the improvement was observed. Finnally, as an application of using wrinkled parts as preform prior to the final calibration, a magnesium alloy tubular part with 50% expansion ratio was formed.

Non-uniform temperature distribution of the main reflector of a large radio telescope under solar radiation

2021 ◽  
Vol 21 (11) ◽  
pp. 293
Author(s):  
Shan-Xiang Wei ◽  
De-Qing Kong ◽  
Qi-Ming Wang
Keyword(s):  
Temperature Field ◽  
Temperature Distribution ◽  
Solar Radiation ◽  
Radio Telescope ◽  
Thermal Imaging ◽  
Uniform Temperature ◽  
Large Radio Telescope ◽  
Uniform Temperature Distribution ◽  
Uniform Temperature Field ◽  
Main Reflector

Abstract The non-uniform temperature distribution of the main reflector of a large radio telescope may cause serious deformation of the main reflector, which will dramatically reduce the aperture efficiency of a radio telescope. To study the non-uniform temperature field of the main reflector of a large radio telescope, numerical calculations including thermal environment factors, the coefficients on convection and radiation, and the shadow boundary of the main reflector are first discussed. In addition, the shadow coverage and the non-uniform temperature field of the main reflector of a 70-m radio telescope under solar radiation are simulated by finite element analysis. The simulation results show that the temperature distribution of the main reflector under solar radiation is very uneven, and the maximum of the root mean square temperature is 12.3°C. To verify the simulation results, an optical camera and a thermal imaging camera are used to measure the shadow coverage and the non-uniform temperature distribution of the main reflector on a clear day. At the same time, some temperature sensors are used to measure the temperature at some points close to the main reflector on the backup structure. It has been verified that the simulation and measurement results of the shadow coverage on the main reflector are in good agreement, and the cosine similarity between the simulation and the measurement is above 90%. Despite the inevitable thermal imaging errors caused by large viewing angles, the simulated temperature field is similar to the measured temperature distribution of the main reflector to a large extent. The temperature trend measured at the test points on the backup structure close to the main reflector without direct solar radiation is consistent with the simulated temperature trend of the corresponding points on the main reflector with the solar radiation. It is credible to calculate the temperature field of the main reflector through the finite element method. This work can provide valuable references for studying the thermal deformation and the surface accuracy of the main reflector of a large radio telescope.

scholarly journals Polarizing effect in natural polymer cellulose

2019 ◽  
pp. 45-46
Author(s):  
N. N. Matveev ◽  
V. V. Saushkin ◽  
N. Yu. Evsikova ◽  
N. S. Kamalova ◽  
V. I. Lisitsyn
Keyword(s):  
Temperature Field ◽  
Low Temperature ◽  
Natural Polymer ◽  
Uniform Temperature ◽  
Polarization Mechanism ◽  
Uniform Temperature Field ◽  
First Time

For the first time, a method based on the registration of polarization and depolarization currents arising in wood in a non-uniform temperature field was used to study the properties of cellulose. The purpose of the method used is to record the relaxation of bound charges with a change in the temperature of the sample under study. It is shown that the detected low-temperature transitions have a crystal-crystal polarization mechanism, and the natural polymer cellulose is an active dielectric.

Non-uniform temperature field and effects of Shanghai 65 m radio telescope

2014 ◽  
Vol 22 (4) ◽  
pp. 970-978 ◽  
Author(s):  
钱宏亮 QIAN Hong-liang ◽  
柳叶 LIU Ye ◽  
范峰 FAN Feng ◽  
金晓飞 JIN Xiao-fei
Keyword(s):  
Temperature Field ◽  
Radio Telescope ◽  
Uniform Temperature ◽  
Uniform Temperature Field

The Composite Tool Design Technologies of Aircraft Composite Parts in Autoclave Forming

2012 ◽  
Vol 426 ◽  
pp. 330-334 ◽  
Author(s):  
Ying Guang Li ◽  
C.Y. Fu ◽  
D.S. Li ◽  
S.M. Wan
Keyword(s):  
Temperature Field ◽  
Fiber Reinforced Composites ◽  
Field Analysis ◽  
Reinforced Composites ◽  
Uniform Temperature ◽  
Composite Component ◽  
Cure Process ◽  
Design Flexibility ◽  
Composite Tool ◽  
Uniform Temperature Field

Aiming at the problems of composites of anisotropic, poor in dimensional and uneven temperature field in the designing of composite tool in autoclave, the techniques of designing the composite tool of aircraft components were constructed, involving in the following aspects: Taking advantage of design flexibility of composites, the thermal expansion coefficient between the moulding board and composite components matched. By analyzing the cure process curve of fiber-reinforced composites, the result that the crisis point without stress between component and tool, which the shape of composite component decided was concluded. By the temperature field analysis, and contrasted with the experimental results, the maximum difference was 4.95°C，after analysis, optimized the structure of the tool, obtaining the relatively uniform temperature field of the board.

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