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Abstract: The failure modes during hydro-forming process are
analyzed, the wrinkling criterion and its affecting factors are given by
elasto-plastic theory. The optimal loading paths are discussed and the
use and control of the wrinkles are numerically simulated. The
experimental results of aluminum and stainless steel tube hydro-forming
conducted in the first set hydro-forming press in China are introduced.
The research results show that the critical axial force for wrinkling is
gradually increased with the increase of the internal pressure. The
loading parameter l =1.0, i. e. the tube is in the pure shear state, is
the optimal loading path. This optimal loading path can avoid the
occurrence of wrinkling and make the thickness unchangeable. The real
loading path should be controlled close to this optimal loading path. It
is pointed out that not all wrinkles are defects and the beneficial
wrinkles can be used to reduce the thinning.
Key words: Internal high pressure forming Hydro-forming Elasto-plastic
instability Numerical simulation
CLC No: TG394
国家自然科学基金资助项目(59975021). Received 20020830, received in revised form
20021110
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