Enhancement on deformation uniformity of double curvature shell by hydroforming process and curved blank-holder surface

2017 ◽  
Vol 92 (5-8) ◽  
pp. 1913-1922 ◽  
Author(s):  
Wei Liu ◽  
Lihui An ◽  
Shijian Yuan
2016 ◽  
Vol 851 ◽  
pp. 163-167
Author(s):  
Dong Yan Lin ◽  
Yi Li

The hydroforming process of the aluminum alloy panel was simulated by the software DYNAFORM. The effects of process parameters (blank holder force, depth of panel and height of draw bead) on springback of the aluminum alloy were investigated. The max springback of the panel was analyzed by weighted scoring method. Then the process parameters were synthetically optimized for the max positive and negative springback. The results showed that the height of draw bead affects obviously the comprehensive springback of the panel. The optimization of the process parameters obtained by the orthogonal experiment can effectively reduce the max springback of the panel.


2009 ◽  
Vol 16-19 ◽  
pp. 500-504
Author(s):  
Zhen Xiu Hou ◽  
Nan Zhang ◽  
En Ren Liu ◽  
Zhi Liu ◽  
An Feng ◽  
...  

To explore geometrical shape, stress distribution, strain distribution and wall thickness of product in the process of polycarbonate hot gas bulge forming, numerical simulation of 4mm PC double curvature and large-area workpiece with the chord 1050mm has been conducted by the finite element software DYNAFORM. The results indicate that the deformation of large-area workpiece starts from blank holder to sheet center, and the maximum latitudinal stress and longitudinal stress is located in the center of PC sheet. The maximum reducing rate is approximate to 6.4%. The experimental results fit well with the numerical simulation.


2011 ◽  
Vol 473 ◽  
pp. 594-601 ◽  
Author(s):  
Hasan Gedikli ◽  
Ömer Necati Cora ◽  
Muammer Koç

This study numerically investigated the effects of process parameter variations such as blank holder forces (800kN-1200kN), strain rates (0.0013/sec, 0.013/sec, 0.13/sec), coefficient of friction (0.05-0.15), temperature (150 °C, 260 °C) and apex angles (0º, 60º, 90º,120º) on warm hydroforming of AA 5754-O sheet blanks. Warm hydroforming process was simulated through hydraulic bulge test with circular and elliptical die openings. Dome height and sheet thinning were selected as control parameters for formability of AA 5754-O sheet blanks. Results showed that the dome height and formed blank thicknesses did not change significantly with the variation of coefficient of friction and blank holder force. Moreover, increasing forming temperature and non-isothermal conditions yielded slightly better formability. On the other hand, increase in strain rate, and elliptical type of bulge test cavity led to significant decreases in dome height and formed part thinning. Another significant finding was that the elliptical bulge test model and isothermal analyses did not reveal the effect of anisotropy for the sheet material concerned.


2012 ◽  
Vol 152-154 ◽  
pp. 1623-1627
Author(s):  
Morteza Hosseinzadeh

In recent years, several sheet hydroforming methods have been introduced by researchers. Despite the advantages of these methods, they have some limitations. The author [1] already proposed a novel sheet hydroforming method that is a combination of the standard and hydromechanical sheet hydroforming processes. The proposed method has the advantages of both processes and eliminates their limitations. In this method, a polyurethane diaphragm was used as a part of die-set to control the blank holder force. In this paper, the effect of polyurethane hardness on the effective parameters of the combined sheet hydroforming die-set such as forming pressure, thickness distribution of formed cup and maximum thinning zone of formed cup was investigated experimentally. It was shown that a softer polyurethane needs to a higher oil pressure to prevent wrinkling in the flange of the part. And tearing occurs at higher level of forming pressure. Also it was shown that by softer polyurethane, better thickness distribution was obtained.


2016 ◽  
Vol 716 ◽  
pp. 963-972
Author(s):  
Gianfranco Palumbo ◽  
Antonio Piccininni ◽  
Pasquale Guglielmi ◽  
Vito Piglionico ◽  
Donato Sorgente ◽  
...  

In this work, the hydroforming process in warm conditions was used for manufacturing an Al-Mg alloy (AA5754) benchmark component displaying different strain levels due to its geometry. The attention was focused on the effect of the rate to increase the forming pressure (PR), strictly related to the strain rate the material is subjected to. In fact, preliminary tensile and Nakajima tests (both at room temperature and in warm conditions) revealed that the mechanical and formability properties of the investigated alloy are strongly affected by the strain rate. Warm Hydroforming tests were conducted in order to investigate both the working temperature and the parameter PR. The Blank Holder Force profile was varied according to an experimentally determined profile able to avoid oil leakages. Experimental results were collected in terms of output variables related to the die cavity filling and to the strain level reached on the component: in such a way a multi-objective optimization could be carried out using the commercial integration platform modeFRONTIER. The best compromise between the high level of the component deformation and the cycle time could be obtained by conducting the warm hydroforming process at the temperature of 250°C and setting the parameter PR equal to 0.1 MPa/sec.


2012 ◽  
Vol 430-432 ◽  
pp. 1286-1289
Author(s):  
Ming He Chen ◽  
Fu Dong Wang ◽  
Jie Xiong

The main defect of shrink flanging wing rib is wrinkling in rubber bladder hydroforming. In the aeronautical field, the side blank holder is usually used to avoid wrinkling. In order to obtain appropriate parameters of side blank holder, it be carried out that the simulation analysis for the process of the high hydraulic press rubber forming processes of high shrink flanging with side blank holder by the ABAQUS finite element software. Besides, the corresponding experiments verified also be implemented. The research results show that the sheet metal tends to wrinkle along with decrease of the blank lap width and increase of these parameters such as the distance between side blank holder and die, the dip angle and fillet radius of the side blank holder.


2013 ◽  
Vol 549 ◽  
pp. 197-204
Author(s):  
Antonio del Prete ◽  
Gabriele Papadia ◽  
Teresa Primo ◽  
Silvia Schipa

Blank shape is one of the most important parameters of sheet metal stamping. In fact it can directly affect the forming quality of parts and it has to be taken in account in sheet hydroforming design. Reasonable blank shape not only can reduce materials and production cost but, also, it can improve the strain distribution of the material and product quality in the hydroforming process. However, it is not easy to find an optimal blank shape because of complexity of deformation behavior and presence of many process parameters like die radius, punch radius, punch speed, blank holder force and friction. In fact, they affect the result of the process i.e. tearing, wrinkling, springback and surface conditions such as earing. Even a slight variation in one of these parameters can result in defects. This paper reports numerical and experimental correlation for axis symmetrical hydroformed component using initial blank with different shape and size. Experimental tests have been carried out through the hydroforming cell tooling, designed by the authors thanks to a research project, characterized by a variable upper blankholder load of eight different hydraulic actuators. Two different initial blank shapes, square and circular, of same material and thickness have been used.


2009 ◽  
Vol 410-411 ◽  
pp. 69-76 ◽  
Author(s):  
M. Ertugrul ◽  
Peter Groche

The hydroforming of sheet metals belongs to deep drawing processes, where the forming capacitiy is performed by a pressure medium. This process is especially suitable for parts with a non-rotationally symmetric geometry. Light-weight structures require particularly weight optimized geometries with a possibility to attach joints or secondary shape elements. Weight and strength optimised structures often use stringer elements to fulfill this requirement. They are used in flat plates or in single curved bodies. The assembling of the sheet stringers is often costly in terms of time and money. Hence, the hydroforming process of those sheet stringers offers a new process chain for the manufacturing of complex, multi-curved hollow parts with pre-attached stiffeners. Thereby, tools and process control strategies are similar to the conventional hydroforming process of blank sheets. This paper describes the hydroforming process of laser welded sheet stringers. It gives a first outline of the potential and the limitations of the new process chain. Blank holder force and the fluid pressure are the main parameters during the hydroforming process.


Author(s):  
Paulo Sergio Olivio Filho ◽  
ADRIANO OLIVEIRA ◽  
Émillyn Ferreira Trevisani Olivio

2003 ◽  
Vol 87 (9) ◽  
pp. 207-213
Author(s):  
Zhiguo Zhang ◽  
Tiejun Lu ◽  
Jingchun Wang

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