摘要
为了改善 Chaboche粘塑性统一本构方程描述第三阶段蠕变的能力 ,按照 Lemaitre有效应力的概念 ,采用 Kachanov损伤演化方程 ,推导了耦合各向同性损伤因子的 Chaboche粘塑性流动方程和硬化方程。当耦合损伤时 ,内变量演化方程形式不变 ,并不显含损伤因子 D。将之用于镍基高温合金 Udimet72 0 Li的蠕变描述 ,得到了该合金的蠕变损伤参数。通过对双轴试样的有限元计算 ,发现了 Kachanov损伤演化方程对单轴和多轴蠕变的预测并不协调。在损伤演化方程中引入多轴损伤因子得到了与实验数据基本一致的蠕变寿命结果。
In order to improve the capability of Chaboche's unified visco-plastic model in describing the tertiary creep, with Kachanov's equation of damage evolution based on Lemaitre's effective stress being used, Chaboche's visco-plastic potential function was utilized to obtain the inelastic flow rule and hardening rule coupling to damage. It is shown that the form of the evolutionary equations of internal variables remains the same, and that the damage variable is not explicit in the equations. The modified constitutive model with damage was applied to the description of the uni-axial and bi-axial creep behaviors of a Ni-based superalloy, Udimet 720 Li, by coding the user's material subroutine, UMAT, in ABAQUS platform. The finite element analysis of cruciform specimens shows that the inconsistency between uni-axial and bi-axial creep modeling capability exists in Kachanov's damage law especially at the time of rupture. The calculated creep behaviors match well with the experimental ones when a multi-axial damage factor is introduced into the damage evolutionary equation.
出处
《航空动力学报》
EI
CAS
CSCD
北大核心
2005年第1期60-65,共6页
Journal of Aerospace Power
基金
欧盟 F P5框架 E3 E发动机中德 JET项目 Disc L ifing项目 ( E0 110 0 3 0 2)
