13-19To reveal the deformation characteristics
and influence of dissimilar thickness on hydro-bugling of tailor-welded tube
(TWT), FEA, experiments and mechanics analysis are conducted. The effects of
length ratio, weld-seam movement and work-hardening on deformation
compatibility are analyzed. It indicates that the plastic deformation occurs
first at the middle zone of the thinner tube, and then extends to the thicker
tube crossing the weld-seam. The expansion occurring on the two parts with
dissimilar thickness is non-uniform, higher the length ratio and higher the
deformation compatibility. Stress-strain analysis reveals that though the whole
TWT suffers biaxial tensile stresses and the biaxial elongation occurs in the
thinner tube, axial compressive strain occurs in the thicker tube. It is
concluded that the mechanism for improving the deformation compatibility is to
induce the deformation in the thicker tube by enhancing the bulging pressure
needed for the thinner tube through changing the stress state of the thinner
tube and flowing stress. Weld-seam movement happens during tailor-welded tube
hydroforming, which induces uneven distribution of axial strain and thinning
ratio in the TWT