Theoretical And Simulation Analysis Of Necking-Bulging Process For A Mini-car Rear Axle

Hydroforming is a new technology which is widely used for technical problemsthat are difficult or unable to solve in conventional mechanical manufacturing processof all kinds of special-shaped cross-section tube in aviation, aerospace and automobilefield. The automobile axle housing which is made by hydroforming process, has highstrength and stiffness, light weight and reasonable wall thickness distribution, nowelding lines, few machining process and high efficiency. Therefore, good economicbenefits and application prospects are processes.Theoretical research and simulation analysis are combined to research thenecking-hydraulic bulging processes of a mini-car rear axle. First, hydraulic bulgingprocesses of an aluminum alloy tube are simulated, simulation and experimentalresults were compared and the correctness of finite element model was verified, basedon this, menus of necking-tube parametrically modeling are developed based onABAQUS software， and the modeling speed of necking tube is improved. Thenecking processes of rear axle are simulated by using ABAQUS. The distribution ofthe stress, strain of successful necking tube were given, and the effect for tubeforming quality of different friction coefficient and the feeding speed of mould areanalyzed. Subsequently, hydraulic bulging processes of a mini car rear axle aresimulated, the reason of generating various defects is explained and formability ofrear axle was analyzed by using FLD, and bulging results of tube under differentloading paths were obtained as well.Results show that, in necking process of rear axle, the friction coefficient issmaller, the forming effect of tube is better. Excessive value of friction coefficient willresult in plastic instability of the material. Suitable mould feeding speed is obtainedthrough analysis, which makes the tube getting a better necking effect.Taking annealing treatment in the final bulging stage of rear axle is beneficial toobtain the reasonable loading path. Wall thickness distribution of tube is reasonableand the bulging results are more ideal as well.This article not only has good theoretical significance and engineeringapplication prospects, also plays an important role to extend the research and masterthe core technology, laying the theoretical foundation of next research and productionof high quality automobile parts as well.