Study On Hydraulic Pressure Bulge Forming Theeory And Experiment Of Thin Tube

Hydroforming, as a important technique of tube finish machining, is used widely in fields of spaceflight, auto and pipeline. The practice of tube bulge shows that the choice of loading route and forming limit of tube is important to the shape and quality of produce. In this paper, influence of loading route and limit forming on shaping of tube produce is studied.This paper thorough analyses the force characteristics of each phase in tube hydraulic shaping, abstractly analyses the variety of loading during the process of tube bulge, puts forward the calculation method of loading of thin free bulge under internal press and axial force, and point out the scope of loading route which should used in tube bulge. In this paper, the forming limit of tube bulge is also been studied adopting forming limit theory and failure theory. It puts forward calculation theory of forming limit of monolayer tube and multiplayer tube bulge, and fetches calculation formulae of forming limit. Based on the theoretic analysis done hereinbefore, this paper simulates and studies the shaping process and loading route of tube bulge using finite element analysis software MARC, puts forward the method of getting forming limit through the connection of simulation and forming limit theory. Then this paper simulates the process of tube tie-in bulge, puts forward the academic gist for the experiment of tube tie-in bulge shaping. The results of simulation prove that suppose used by theoretic analysis is right. The forming limits gained through theoretic analysis have well identical with simulation. The results of experiment prove that the method used by theoretic analysis and simulation is ring, provides dependable gist and technics criterion for manufacture of tube procedure using bulge technology, and has an important theoretic meaning and merit to popularize.