Design an Effective Solution for Stretch Forming of Sheet Metal with a Shorter Free Edge

2013 ◽  
Vol 395-396 ◽  
pp. 941-944
Author(s):  
Qi Gang Han ◽  
Qiang Zhang ◽  
Ming Zhe Li ◽  
Shi Zhong Su ◽  
Wen Ke Yang ◽  
...  
Keyword(s):  
Finite Element ◽  
High Speed ◽  
Free Edge ◽  
Effective Solution ◽  
High Speed Train ◽  
Stretch Forming ◽  
High Quality ◽  
Forming Technology ◽  
Element Simulation

To remove the disadvantage of conventional stretch forming machine (CSFM), a flexible stretch forming machine (FSFM) has been developed by authors recently. Based on finite element simulation and experiments, the advantages of FSFM have been detailed discussed. Our results indicated that the discrete multi-gripping jaws can swing and rotate in any direction automatically, which can solve the wasteful production of CSFM by increase the rate of materials utilization and close-fitting dies. Furthermore, the value of springback and thickness gradient in the parts formed by discrete multi-gripping jaws is smaller compare with that of integrally gripping jaws, which can help to achieve a high quality of stretch forming parts. A series of double-curved sheet panels have been formed by FSFM easily and used in the cabinet covers of high-speed train and the Dongdaemun Design Park building successfully. This work has a strong value in enhance the way to flexible and reproducible stretch forming technology.

Vibration Control of HSM of Thin-Wall Titanium Alloy Components Based on Finite Element Simulation

2016 ◽  
Vol 836-837 ◽  
pp. 304-309 ◽  
Author(s):  
Kang Zhao ◽  
Hong Hua Su ◽  
Lin Jiang He ◽  
Ying Zhi Liu
Keyword(s):  
Finite Element ◽  
Titanium Alloy ◽  
High Speed ◽  
Element Model ◽  
Fixture Design ◽  
Thin Wall ◽  
Element Simulation ◽  
Flexible Workpiece ◽  
Fixture System

During high-speed machining, the vibration will result in poor workpiece surface and damage the cutting tool as well as the machine tool. It will limit the productivity and lower the quality of thin-wall titanium alloy components. Moreover, vibration occurrence is strongly affected by the dynamic response of the whole system, particularly the stiffness of workpiece-fixture system. Improper fixture layout is prone to generate vibration, especially for the flexible workpiece. Hence, it’s necessary to suppress the vibration and improve the fixture design. In this work, a finite element model of the workpiece-fixture system is built. Based on this model, the laws of the natural frequency and vibration modals under different fixturing methods are obtained, which can be used to refine fixture design. With several additional auxiliary supports, the stiffness of the workpiece-fixture system is improved and the result showed that, the natural frequencies of thin-wall titanium alloy components can be improved to a level which is too high to be reached by tool’s excitation. The result of this study is helpful to design the optimum fixture scheme of thin-wall titanium alloy components.

Design of a New Type Flexible Stretch-Forming Machine

2013 ◽  
Vol 690-693 ◽  
pp. 2218-2221 ◽  
Author(s):  
Qi Gang Han ◽  
Ming Zhe Li ◽  
Qiang Zhang ◽  
Ya Dong Chen ◽  
Wen Zhi Fu
Keyword(s):  
Sheet Metal ◽  
Metal Forming ◽  
High Speed ◽  
High Speed Train ◽  
Stretch Forming ◽  
Sheet Metal Parts ◽  
Large Size ◽  
Forming Technology ◽  
Plastic Forming ◽  
New Type

Stretch forming machine (SFM) is most effective plastic forming equipment for large-size, thin and flat-deformation parts, which can decrease the springback phenomenon in sheet metal forming. In order to enhance the performance of SFM, a flexible stretch forming machine (FSFM) was developed by the authors successfully, which is made up of jaw clamping mechanisms, stretching mechanisms, universal push-pull mechanisms, and a carriage. Our experimental results indicated that the rate of materials utilization and close-fitting dies can be increased to 80 %. In addition, FSFM can reduce the complex of control-system and decrease the expense of machine sharply. FSFM have been used for double-curved sheet metal manufacturing successfully, such as the cab of high-speed train. This work has a strong value in enhance the stretch forming technology for double-curved sheet metal parts.

Research on the Effects of Welding Sequence on Welding Residual Stress of High-Speed Train Based on SYSWELD

2011 ◽  
Vol 399-401 ◽  
pp. 1806-1811
Author(s):  
Yong Hong Chen ◽  
Peng Chen ◽  
Ai Qin Tian
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
High Speed ◽  
Element Model ◽  
Welding Residual Stress ◽  
High Speed Train ◽  
Distribution Law ◽  
Element Analysis ◽  
Welding Sequence ◽  
Maximum Residual Stress

The finite element model of the roof of aluminum high-speed train was established, double ellipsoid heat source was employed, and heat elastic-plastic theory was used to simulate welding residual stress of the component under different welding sequence based on the finite element analysis software SYSWELD. The distribution law of welding residual stress was obtained. And the effects of the welding sequence on the value and distribution of residual stress was analyzed. The numerical results showed that the simulation data agree well with experimental test data. The maximum residual stress appears in the weld seam and nearby. The residual stress value decreases far away from the welding center. Welding sequence has a significant impact on the final welding residual stress when welding the roof of aluminum body. The side whose residual stress needs to be controlled should be welded first.

Phase Algorithm Integrating Direct-Correlation and Four-Step Phase-Shifting for Electronic Speckle Pattern Interferometry

2013 ◽  
Vol 448-453 ◽  
pp. 3696-3701
Author(s):  
Yan Bin He ◽  
Xin Zhong Li ◽  
Min Zhou
Keyword(s):  
High Speed ◽  
Speckle Pattern ◽  
Phase Shifting ◽  
Electronic Speckle Pattern Interferometry ◽  
High Speed Camera ◽  
Dynamic Measurements ◽  
High Quality ◽  
Correlation Algorithm ◽  
Phase Map

A phase-shifting algorithm, called a (4,4) algorithm, which takes four phase-shifting interferograms before a specimen is deformed and four interferograms after a specimen is deformed, is presented first. This method is most widely used for phase extraction. Its drawback limited it to be used in dynamic measurements. Also shown is an algorithm called a (4,1) algorithm that takes four phase-shifting interferograms before a specimen is deformed and one interferogram after a specimen is deformed. Because a high-speed camera can be used to record the dynamic interferogram of the specimen, this algorithm has the potential to retain the phase-shifting capability for ESPI in dynamic measurements. The quality of the phase map obtained using (4,1) algorithm is quite lower compared to using (4,4) algorithm. In order to obtain high-quality phase map in dynamic measurements, a direct-correlation algorithm was integrated with the (4,1) algorithm to form DC-(4,1) algorithm which is shown to improve significantly the quality of the phase maps. The theoretical and experimental aspects of this newly developed technique, which can extend ESPI to areas such as high-speed dynamic measurements, are examined in detail.

Simulation of hot high-speed yielding of intermetallic titanium alloy VTI-4 under conditions of high-speed loading

2020 ◽  
Vol 0 (12) ◽  
pp. 10-16
Author(s):  
V.V. Avtaev ◽  
◽  
D. V. Grinevich ◽  
A. V. Zavodov
Keyword(s):  
Finite Element ◽  
Titanium Alloy ◽  
Strain Rate ◽  
Finite Element Simulation ◽  
Modulus Of Elasticity ◽  
High Speed ◽  
Residual Deformation ◽  
Test Results ◽  
Element Simulation ◽  
The Relationship

Yielding tests of VTI-4 alloy specimens have been carried out at temperature 1010 °C under conditions of high-speed loading. Based on the test results the modulus of elasticity as well as axial and radial residual deformation values in the end and central zones for each loading stage were determined. Fitting criteria for finite element simulation and the experiment are proposed with tracing VTI-4 alloy diagram deformation at temperature 1010 °C and strain rate of 2.5 sec–1. As a result of finite element simulation the relationship between the material structures obtained during high-speed yielding and the deflected modes in different zones was determined.

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