大型复杂薄壁壳体多道次旋压过程中的壁厚变化

基于ABAQUS/Explicit和Standard建立的包含回弹与退火的大型复杂薄壁壳体多道次旋压全过程模拟模型,分析了该过程中壁厚的分布与变化及工艺参数对壁厚的影响规律。结果表明,壁厚减薄经历了剪切减薄和拉薄两个阶段,壁厚剧烈减薄部位位于旋轮后方的环带并向工件口部移动,而且其值逐渐减小;壁厚沿工件母线方向分布不均匀,沿周向分布较均匀;回弹对壁厚的分布影响不大。摩擦系数在一定范围内的增大,可以有效地抑制第一道次旋压过程中壁厚过度减薄的发生,使壁厚分布更均匀;而旋轮进给比对工件壁厚的影响与摩擦系数的作用相反。在后续道次旋压过程中,工件壁厚差随着摩擦系数的增大先减小后增大,随着旋轮进给比的增大逐渐减小。这些结果可为大型复杂薄壁壳体多道次旋压成形参数的确定和优化设计提供理论依据。

Wall thickness variation during multi-pass spinning of large complicated shell

Using the 3D FEM model for the whole multi-pass spinning of a large complicated shell,including not only spinning process but also springback and annealing processes,established based on software ABAQUS/Explicit and Standard,the features of wall thickness and influence laws of process parameters on wall thickness during the spinning process have been obtained.The results show that wall thickness reduction undergoes shear deformation thinning and stretch thinning,the acutely thinning of wall thickness occurs at the ring behind the roller,then it tranfers to the open end and its value decreases along the forming process.Wall thickness distributes unevenly along the generating line but evenly along the circumference directions of the workpiece.Unloading springback brings about unobvious variation on wall thickness.The increase of the friction factor to some extent can restrain the excessive thinning of wall thickness during the first pass spinning,thus make wall thickness distribute more evenly.But the effect of roller feed ratio on the wall thickness is contrary to the friction's effect.For the succeeding pass spinning processes,wall thickness decreases firstly then increases with the growing of the friction factor,but it decreases with the roller feed ratio.The results may be a helpful tool for determination and optimization of process parameters of multi-pass spinning process of the large complicated shell.