航天铝合金深腔零件整体成形预制坯优化设计

提出航天铝合金深腔零件整体成形方法,开展预制坯优化设计。对比分析直筒和变径筒两种预制筒坯结构变形规律,数值模拟研究了底部圆角对开口球形件液压成形的影响规律。以直径D=450 mm的球形整体零件为验证对象,进行底部圆角r=60 mm的变径筒形件的液压成形试验验证。结果表明:直筒坯液压成形时,赤道位置发生破裂;变径筒坯液压成形时,当胀形压力为16 MPa即发生贴模;液压成形时,筒端口自适应补料,所以上半球的壁厚分布均匀;随着底部圆角越大,筒底部减薄越小,筒壁厚越均匀;当底部圆角为r=60 mm时,开口球壳赤道位置壁厚减薄最严重,减薄率为11.1%,球底部减薄率为9.8%,开口球壳上半球壁厚差为0.17 mm,下半球壁厚差为0.43 mm。

Optimization Design of Integrally Precast Aluminum Alloy Deep-Cavity Shell Parts

The hydroforming method for the integral forming of aerospace aluminum alloy deep-cavity shell parts is proposed, and the optimization design of precast straight-wall and necked cups are designed. The structural deformation rules of two kinds of precast cups, i.e., straight-wall cups and necked cups, are compared and analyzed, and the effects of the bottom radius on the hydroforming of a spherical shell with an opened end are studied by numerical simulation. Hydroforming experiments are carried out on the necked cup with a bottom radius of 60 mm and a diameter of 450 mm. The results show that when the straight-wall cup is hydroforming, there are cracks at the equator position; when the bulging pressure is 16 MPa, the necked cup is hydroformed into the designed spherical shell successfully. During the hydroforming process, the opening end of the necked cup flows into the die freely, and thus the wall thickness distribution of the upper spherical shell is uniform. The larger the bottom radius is, the less the thickness reduction at the bottom is, and the more uniform the wall thickness is. When the bottom radius is 60 mm, the wall thickness of the spherical shell with an opened end reduces the most at the equator position where the thinning ratio is 11.1%, and the thinning ratio at the bottom is 9.8%. The wall thickness difference of the upper half spherical shell is 0.17 mm, and that of the lower half spherical shell is 0.43 mm.