Constitutive Modelling and Formability Evaluation of Tubular Materials for Hydroforming Processes

摘要

Testing and modelling of deformation behavior and formability of tubular materials is one critical work for hydroforming.Recent research works and main progresses on constitutive modelling and formability evaluation of typical tubes are presented in this paper.A unified analytical model for stress and strain components together with a linear model for pole thickness change in hydro-bulging test has been proposed and successfully validated by experiments.A testing system for characterizing the mechanical properties of tube under bi-axial stress state similar to real hydroforming process has been developed and applied.Based on another newly developed system with two independent intensifiers, the influence of normal stress on the formability of thin-walled tubes has been verified by experiments.The expansion deformation of tube in square-section die and the wrinkling behavior of tube under combined internal-external pressure have also been investigated.