Research On Bi-layered Tubular Components Forming By Hydroforming

Bimetallic tubing can be produced with two kinds of metal. Indeed combined tubes givescombined propertied of strength, stiffness and corrosion resistance that single tubes cannot provide.The hydroforming technique is used to produce seamless components form metal tubes. Comparedwith conventional metal forming processes, tube hydroforming(THF) has the merits of a reduction inwork procedure, cost and product weight.A number of research works have been reported in the literature in recent years on the single tubehydroforming process. And single tube hydroforming has been a mature process which is widelyapplied to industrial production. However, in the field of the bi-layered tube hydroforming process,the numerical simulation of the plastic forming process, the equipment and the loading path etc. isbecoming a hot point in domestic and international research. The sealability of equipment is one ofthe key issues that must be solved. In this work, a finite element study along with experiments hasbeen used to research the bi-layered tube hydroforming process. The main researches are as follows.In this paper, finite element simulation(using ABAQUS) with orthogonal design were used tounderstand the geometrical factors(length of tubes, wall thickness of tubes, clearance of two tubes,radius of die) and their effects on the bugle height and thickness distribution of hydroformed part.Also we obtained the optimal values of the parameters. Self-feeding simulation approach was used tooptimize the loading paths for bi-layered tube hydroforming. The intent of the optimization procedureis to determine the loading paths that would result in a product with a maximum bugle height, auniform thickness distribution.Based on the existing hydroforming device and the feature of bi-layered tube hydroforming, thedissertation takes an exploratory study on the key technique of the integral structure, the hydrauliccontrolling system, the THF die system and the sealing system and so on. A THF equipment had beenresearched and developed, its maximal internal pressure is25MPa.The internal pressure and the axialdisplacement can be controlled. It is the experiment tool for research.The hydroforming process of aluminum and copper had been discussed. The optimal parametersof forming die and forming process were obtained, and carried on the hydroforming experimentsunder different technological parameters. Completed the development of the samples, and thenanalyzed the existing problems which provide reference for subsequent research.