(1. 中南大學 材料科學與工程學院，長沙 410083；
2. 中南大學 有色金屬材料科學與工程教育部重點實驗室，長沙 410012)
摘 要: 本文提出了一種結合有限元模擬預測金屬板材成形極限曲線(FLC)的失穩(wěn)準則-最大應變速率失穩(wěn)準則。該準則考察試樣所有單元體的整個變形歷史，通過厚向應變及厚向應變速率隨時間的變化來判定頸縮時刻和頸縮位置，可以應用于變形過程中存在應變路徑變化的情況。對比AA3003板材預測與實驗結果發(fā)現(xiàn)，本方法所預測的FLC整體上與實測結果符合較好，優(yōu)于傳統(tǒng)M-K理論的計算結果。
關鍵字: 失穩(wěn)準則；頸縮；成形極限曲線；有限元模擬
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Central South University, Changsha 410012, China）
Abstract:In this work, an instability criterion (maximum strain-rate instability criterion) was proposed to predict forming limit curve (FLC) of sheet metal based on finite element simulation. The criterion analyzed the entire deformation history of all elements in the specimen. The necking time and necking position were identified by tracking the temporal change of thickness strain and thickness strain-rate. The criterion could be applied to deformation processes with possible strain path changes. Application to the AA3003 aluminum sheet shows that the FLC predicted by the present method is in overall good agreement with the experimental results, and it is better than that predicted by the traditional M-K theory.
Key words: instability criterion; necking; forming limit curve; finite element simulation
