文档介绍：International Journal of Mechanical Sciences 46 (2004) 263–283
Hydroforming of aluminum extrusion tubes for
automotive applications. Part I: buckling, wrinkling and
bursting analyses of aluminum tubes
E. Chu∗,YuXu
Product Manufacturing Division, Alcoa Inc., Alcoa Technical Center, Alcoa Center, PA 15069-0001, USA
Received 22 November 2002; received in revised form 7 January 2004; accepted 4 February 2004
Abstract
Three possible failure modes have been identiÿed in tube hydroforming: buckling, wrinkling and bursting.
A general theoretical framework is proposed for analyzing these failure modes as an elastoplastic bifurca-
tion problem. This framework enables advanced yield criteria and various strain-hardening laws to be readily
incorporated into the analysis. The e8ect of plastic deformation on the geometric instability in tube hydro-
forming, such as global buckling, axisymmetric wrinkling and asymmetric wrinkling, is precisely treated by
using the exact plane stress moduli tensor. A mathematical formulation for predicting the localized condition
for bursting failure is established herein. Furthermore, the critical conditions governing the onset of buckling,
axisymmetric wrinkling and asymmetric wrinkling are derived in closed-form expressions for the critical axial
compressive stresses. Closed-form solutions for the critical stress are developed based on Neale–Hutchinson’s
constitutive equation and an assumed deformation theory of plasticity. It is demonstrated that the onset of
asymmetric wrinkling always requires a higher critical pressive stress than the axisymmetric one un-
der the context of tube hydroforming with applied internal pressure and hence the asymmetric wrinkling mode
can be excluded in the analysis of tube hydroforming. Parametric studies show that buckling and axisymmet-
ric wrinkling are strongly dependent on geometric parameters such as t0=r0 and r0=‘0, and that axisymmetric
wrinkling is the predominant mode for sho