As a new type of metal sheet, titanium/iron composite sheets are crucial in various fields. However, in the forming of the curved shells of the titanium/iron composite sheets with small thickness-to-diameter ratios, sidewall wrinkling is extremely easy to form, and it is hard to control. In this paper, an experimental setup for hydro-mechanical deep drawing was designed, and sidewall wrinkling on the hemispherical shell with a flat bottom and 0.47% thickness-to-diameter ratio of titanium/iron composite sheets was effectively suppressed while avoiding splitting. Mechanical and numerical analyses were conducted to reveal the deformation mechanism, and the effect of chamber pressure was studied. The forming defects, thickness, and stress distributions were determined to reflect the deformation behavior. Results show the greater the chamber pressure, the more significant the effect of wrinkling suppression. When the chamber pressure reaches 20 MPa, the sidewall wrinkles disappear. Enough hydraulic pressure can produce a strong backward-bulging effect, which increases the wrinkling suppression pressure and improves plastic deformation instability. Moreover, the stress state of the sidewall changes under the action of hydraulic pressure, thereby changing the in-plane deformation behavior. Thus, the wrinkles already formed in the earlier stage of sidewall formation were adjusted after contact with the punch. The forming process has considerable potential to fabricate thin-shell components.

中文翻译：

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钛/铁复合板曲面壳液压机械拉深中侧壁起皱的抑制

钛/铁复合板材作为一种新型金属板材，在各个领域都发挥着至关重要的作用。然而，小厚径比的钛/铁复合板材弯曲壳成型时，极易形成侧壁起皱，且难以控制。本文设计了液压机械拉深实验装置，有效抑制了厚径比为0.47%的钛/铁复合板材的平底半球壳侧壁起皱，同时避免了劈裂。通过力学和数值分析来揭示变形机制，并研究了腔室压力的影响。确定成形缺陷、厚度和应力分布以反映变形行为。结果表明，腔室压力越大，抑皱效果越显着。当腔室压力达到20 MPa时，侧壁皱纹消失。足够的液压可以产生强烈的向后胀形效果，增加了抑皱压力，改善了塑性变形的不稳定性。而且，在水压力的作用下，侧壁的应力状态发生变化，从而改变面内变形行为。因此，在与冲头接触之后，在侧壁形成的早期阶段已经形成的褶皱被调整。成形工艺在制造薄壳部件方面具有巨大的潜力。