摘要
在350 ℃下对T225NG钛合金进行了单轴棘轮试验研究,提出了一种新的带有记忆面的黏塑性本构模型.引入了能记忆最大应变的记忆面,在记忆面内和面上采用不同形式的塑性流动律,将单调拉伸响应和循环响应独立开来,简化了模型参数的确定方法.在背应力随动硬化演化方程中引入了等效应变门槛值,可较好地描述T225NG钛合金应力 应变曲线的屈服平台及其后的强化效应.加入黏性指数修正,可描述棘轮应变率随循环次数迅速衰减的试验现象.将模型应用于 T225NG钛合金 350 ℃单轴棘轮行为描述中,对饱和棘轮应变的预测结果与试验结果吻合较好.
The uniaxial ratcheting behavior of T225NG titanium alloy at 350°C was experimentally investigated. A new visco-plastic constitutive model with the memory surface was presented. A memory surface for maximum strain was introduced and different plastic flow rules were applied according to the memory surface. The monotonic tensile response and cyclic response were separated and the determination of constants in the model was simplified. The threshold of equivalent strain was introduced into the evolution equation for kinematic hardening back stress and the yield platform and hardening effect were described exactly. To describe the experimental phenomenon that ratcheting strain rate decreases quickly with the increasing of cyclic number, the modification of viscosity exponent was adopted. The model was applied to simulation for uniaxial ratcheting behavior of T225NG alloy at 350°C, and demonstrated a satisfied agreement of the simulated results with the experimental ones.
出处
《西安交通大学学报》
EI
CAS
CSCD
北大核心
2005年第3期321-324,共4页
Journal of Xi'an Jiaotong University
基金
国家自然科学基金资助项目(19772041)
核燃料与材料国家重点实验室开放基金资助项目(51481070101QT2201).
关键词
棘轮
本构模型
高温
钛合金
Computer simulation
Cyclic loads
Mathematical models
Strain
Stress analysis
Viscoplasticity
