摘要
采用Chaboche统一粘塑性本构方程 ,对Udimet72 0Li在 70 0℃时的单调拉伸、循环加载及蠕变特性等复杂的高温变形现象进行了建模研究 .探讨了Chaboche本构理论对这些变形现象进行建模的形式 ,并特别针对快速各向同性软化和非对称循环加载时的平均应力松弛现象 ,对Chaboche本构理论进行了修正和变化 .将经过修正的Chaboche本构理论 ,与Levenberg Marquadt非线性优化算法相结合 ,编制了材料参数优化程序 ,得到了材料参数值 .研究表明 ,经过修正的Chaboche本构模型可较好地建模镍基高温合金Udimet 72
The mechanical deformation of a nickel-based superalloy Udimet 720 Li was modeled simultaneously by the Chaboche unified viscoplastic constitutive theory under tensile, cyclic and creep loading conditions at 700°C. To describe the phenomena of cyclic relaxation of mean stress under strain controlled cyclic loading and fast isotropic softening during unloading, the equations of internal variables of the theory were modified. A program code of parameter optimization was compiled with one-dimentional Chaboche model by Levenberg-Marquadt nonlinear algorithm. A global strategy for model parameters optimization was proposed, which produced good results. The numerical simulations show that this modified Chaboche model has sufficient capability of modeling various mechanical behaviors under complex loading conditions.
出处
《北京航空航天大学学报》
EI
CAS
CSCD
北大核心
2004年第8期727-731,共5页
Journal of Beijing University of Aeronautics and Astronautics
基金
欧盟FP5框架E3E中德JET项目 (E0 110 0 3 0 2 )
关键词
粘塑性
本构方程
循环棘轮
平均应力松弛
高温合金
参数优化
Creep
Deformation
Models
Nickel
One dimensional
Optimization
Strain
Stress relaxation
Viscoelasticity
