(上海交通大学国家模具CAD工程研究中心， 上海 200030)
摘 要: 以Lemaitre 的4个基本要素， 即损伤变量、 各向同性损伤假设、 有效应力、 应变等效性假设， 以及热力学和损伤只发生在拉伸应力的塑性变形下的假设为基础， 提出了一个韧性损伤准则， 它能解释自由均匀镦粗的自由表面无裂纹的现象。
关键字: 体积成形 韧性损伤 破坏准则
（Ji Guojin, Peng Yinghong and Ruan Xueyu）
Abstract:Based on Lemaitre's four basic elements, such as damage variable, hypothesis of isotropy, concept of effective stress and hypothesis of strain equivalence, and thermodynamics as well, and also on the author's hypothesis that damage can only be developed on plastic deformation with tensile stress, a new model of isotropic ductile damage was derived. The new model can explain that on the free surface of free homogeneous upsetting there is no ductile fracture.
Key words: metalforming ductile damage criterion of ductile damage
