NUMERICAL SIMULATIONS OF PRODUCTION TECHNOLOGY OF REAR SUSPENSION SUB-FRAME MEMBER BY HYDROFORMING
Abstract
Tendency in automotive industry is headed to the reduction of automobile weight. Besides the usage of modern high strength steels new forming methods are approaching. One of these technologies is hydroforming. This contribution deals with cold hydroforming technology and its application in automotive industry. There has been designed a production technology of rear suspension sub-frame member made of bended tube semi-finished product. For simulation of this technology by FormFEM software product was used. Production sequence of rear suspension sub-frame member begins with press preforming operation. In this operation intermediate gets an appropriate shape for next processing by hydroforming. Simulation shows localization of deformation in points of maximum pipe bend without the change of wall thickness. Maximum value of strain intensity was ?i < 0,1. Critical operation is hydroforming, in which the part gets its definitive shape. After performing, the attained shape allows easy placing of intermediate into the hydroforming die. Performing permits the minimization of wall thickness and lowers the possibility of crack creation, too. Besides the analysis of shape and wall thickness change, the effective strain in both cross and longitudinal cut of part was analyzed as well. Wall thickness changes are irregular and depend on geometric characteristics of tool and intermediate. Strain intensity values are between ?i = 0,1 – 0,45 and also depend on the shape of tool and intermediate. The conclusion deals with the possibilities of numerical simulations by designing new technologies and opportunities for optimalizations of already established ones with emphasis on automotive industry.
Keywords: Finite element method|numerical simulation|hydroforming|automotive industry|tube|optimization of technological process|
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