Investigation of Manufacturing Processes of the Metallic CNG Pressure Vessels

Document Type : Persian


1 Assistant Professor, K. N. Toosi University of Technology, Faculty of Mechanical Engineering

2 M.Sc., K. N. Toosi University of Technology, Faculty of Mechanical Engineering


CNG vessels are used in many vehicles.  Mass production of CNG pressure vessels requires exact understanding of process effective parameters.  In this paper, the numerical analysis has been used to study the manufacturing parameters.  The entire manufacturing processes, including deep drawing, redrawing and ironing, of an aluminum liner sample of CNG pressure vessel (without spinning) have been simulated by Finite Element technique.  The deep drawing process has been modeled by using flat dies.  Then, drawing force and wall thickness variations have been studied.  In order to achieve the final diameter of the liner, the redrawing process has been implemented in a flat die.  To obtain a uniform wall thickness, the ironing process has been simulated in two stages, and the required force and the change of wall thickness for each process have been recorded.  The results of this paper have been compared with the published results obtained by other researcher and found a good correlation between them.


[2]        Choi Chul Kim J.C., Jung S.Y., Development of an automated design system of a CNG composite vessel using a steel liner manufactured using the DDI process. Int. J. Adv. Mfg. Tech., Vol. 24, , 2004, pp. 781–788.
[3]        Vardga L., Nagy A., Kovacs A., Design of CNG tank made of Aluminum and Reinforced Plastic, Composites, Vol. 26, Issue 6, , 1995, pp. 457-463.
[4]        Allen S.j., Mahdavian S.M., The effect of lubrication on die expansion during the deep drawing of axisymmetrical steel cups, J. Material Processing Technology, Vol. 199, 2008, pp. 102-107.
[5]        Sedighi M.  & Rasti M. , An investigation on manufacturing process parameters of CNG pressure vessels, Int. J. Adv. Mfg. Tech.,
Vol. 38, No. 9-10, 2008, pp. 958-964.
[6]        Hrivnak A., Sobotova L., The influence of the deformation aging and the conditions of stress on the properties of the deep drawing steel sheet, J. Material Processing Technology,Vol. 34, 1992, pp. 425-430.
[7]        Date P.P., Padmanabhan K.A., On the prediction of the forming limit diagram of sheet metals,  Int. J. Mechanical  Science , Vol. 34 (5), 1992, pp. 363-374.
[8]        Yossifon S., Tirosh J., On the dimensional accuracy of deep drawing products by hydroforming processes, Int. J. Mech. Sci. 33 (4), pp. 279-295, 1991
[9]        Thiruvarudchelvan S., N.H. Loh, Drawing of cylindrical and hemispherical cups using an improved tooling for friction-actuated blank holding, J. Material Processing Technology, Vol. 37, pp. 267–280, 1993
[11]    NAM J. & Seop HAN K., Finite Element Analysis of  deep Drawing and Ironing Process in the Steel D&I Canmaking, ISIJ.
[12]     ABAQUS Version 6.7 Documentation, ABAQUS Analysis User’s Manual, 2007.