晶体塑性模型在体心立方金属板料成形极限计算中的应用

Forming Limit Analysis of BCC Sheet Metal by Using Crystalline Plasticity Model

结合M-K理论,将率相关的晶体塑性模型用于具有初始织构的体心立方(BCC)多晶体金属板坯成形极限(FLD)计算.假设沟槽内外变形均匀,在沟槽边界处满足协调条件和应力平衡条件;在塑性变形中BCC晶体最多有24个滑移系开动,在晶体黏弹塑性模型中考虑潜在硬化效应,并分析了潜在硬化和板坯织构演化对成形极限应变的影响.结果表明,与不考虑潜在硬化相比,考虑潜在硬化时的成形极限明显较低,且发生缩颈的区域更集中.

A rate-dependent crystal plasticity model was applied combined with M-K approach to predict forming limit diagram （FLD） for BCC sheet metals with initial texture. The deformations inside and outside the band of strain localization are assumed to be homogeneous, meanwhile the compatibility and equilibrium conditions are enforced on the band-matrix interfaces. 24 distinct slip systems are considered for BCC crystal, and the effect of latent hardening is involved in an elastic-viscoplastic polycrystalline model. The results indicate that the forming limit curve with latent hardening is lower than that without latent hardening, and the localized region is more concentrated.