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An investigation into the formability and processes of GLARE materials using hydro-bulging test
Liu Shichen,Lang Lihui,Guan Shiwei 한국정밀공학회 2019 International Journal of Precision Engineering and Vol.20 No.1
Our research mainly focuses on investigating the formability and processes of GLARE materials in the hydro-bulging test. Finite element simulation software ABAQUS/Explicit is applied to study the state of stress and strain as well as wall thickness distribution while experiments have done to validate the simulation results. The results indicate that cavity pressure and blank holder force have a significant effect on the forming behavior compared with traditional metal blanks. Curing process is also introduced in the production stage after first forming step. This study will increase the application of composite laminate manufacturing and open new ways for specialists working on high-strength lightweight material for future research.
Gaoshen Cai,Lihui Lang,Kangning Liu,Sergei Alexandrov,Dongxing Zhang,Xiying Yang,Chan Guo 대한금속·재료학회 2015 METALS AND MATERIALS International Vol.21 No.2
Confirmation of material properties is an important research area for determining metals deformation behavior. In order to research the effect of flow stress calculation on aluminum alloy sheet deformation behavior,warm sheet bulging test was carried out to obtain bulging height - pressure curves with different bulging heightsand diameters in this study. Based on the bulging parts profile data measured by three coordinate measuringmachine, the least square circle fitting radius were fitted. Existing theoretical models for radius of curvatureand thickness were compared and best models were selected to obtain more accurate stress - strain curves bycalculating the bulging flow stress. Combination model was used to calculate the bulging height - pressurecurves obtained by bulging test and the stress-strain curves with different temperatures and pressure rates wereobtained. A monotonous increasing function was resulted which is of great significance in the area of formabilityand deformation behavior of warm sheet hydroforming.
Study on Hydroforming Process and Springback Control of Large Sheet with Weak Rigidity
Sun Zhiying,Lang Lihui 한국정밀공학회 2017 International Journal of Precision Engineering and Vol.18 No.6
The control of instability and springback about large sheet with weak rigidity is difficult in the process. The hydroforming process of aluminum alloy engine cover, springback prediction and compensation were analyzed, and the manufacturing method of parts with high precision was obtained. In this paper, the effect of drawbead, pressure versus punch stroke, and blank holder force on the thinning rate of the plate was analyzed, and the phenomenon of wrinkling and fracture was judged according to the forming limit diagram. And springback is predicted through the method of the finite element and the surface of die was compensated by the iterative method. The results show that the quality of large aluminum alloy plate with weak rigidity is improved, the cost of the mould is reduced by the compensation, and the period of mold repair and commissioning is reduced by the sheet hydroforming, which is the flexible manufacturing process. Springback of large aluminum alloy sheet with weak stiffness is within 10mm through process optimization, and the surface of die was compensated in local region. The springback not only has been effectively controlled, but the accuracy of dimensional also is more than 90% of ± 0.5 mm.
RESEARCH OF DIFFERENT PROCESSES FOR FORMING FIBER METAL LAMINATES
Dmitrii Chernikov,Yaroslav Erisov,Ilia Petrov,Sergei Alexandrov,Lihui Lang 한국자동차공학회 2019 International journal of automotive technology Vol.20 No.Supp
The paper presents the results of forming rifts in five-layer fiber reinforced metal polymer laminates by electromagnetic forming. During the experimental studies the discharge energy of the electro-magnetic machine was varied in such a way as to achieve different depths of the rift. Samples obtained by electro-magnetic forming were compared with control samples obtained by forming using a rubber pad under static loading. The strain state of the samples was analyzed using an digital image correlation system Vic-3D. The experimental research of fiber reinforced metal laminates forming under the influence of pulse magnetic field has shown the possibility of formability increasing due to change of strain state: the rift zone is dominated by compressive circumferential strains, rather than tensile radial strains as during conventional rubber pad forming.