非线性连续损伤模型在汽轮机转子低周疲劳分析中的应用  

APPLICATION OF NONLINEAR CONTINUOUS DAMAGE MODEL ON LOW CYCLIC FATIGUE ANALYSIS OF STEAM TURBINE ROTOR

作　　者：荆建平[1] 孙毅[2] 夏松波[1] 冯国泰[1] 

机构地区：[1]哈尔滨工业大学能源学院,黑龙江哈尔滨150001 [2]哈尔滨工业大学航天工程与力学系,黑龙江哈尔滨150001

出　　处：《中国电机工程学报》2001年第10期28-32,共5页Proceedings of the CSEE

基　　金：国家重点基础研究专项经费资助项目 (G19980 2 0 32 1)~~

摘　　要：针对当前汽轮机转子低周疲劳寿命估算存在较大误差的问题 ,引进了非线性连续损伤力学模型进行汽轮机转子的低周疲劳损伤分析。首先对国产 6 0 0MW汽轮机高压转子在冷启动和滑参数停机等典型工况下的瞬态温度场和热应力场进行了弹塑性有限元分析 ,进而对热应力引起的低周疲劳损伤进行了估算 ,疲劳损伤的估算分别采用了非线性连续损伤力学模型和目前工程上广泛采用的线性损伤累积理论。2种方法的估算结果表明 :由于线性累积损伤理论是基于单轴假定之下 ,没有考虑多轴应力的影响 ,在寿命预测时 ,高估了转子的寿命 ;而非线性连续损伤力学模型不仅考虑了多轴复杂应力的影响而且正确地反映了低周疲劳损伤的非线性累积过程 ,其分析结果更接近实际。For the problem that there is bigger error in the life assessment of low cycle fatigue of turbine rotor,a nonlinear continuous damage mechanics model is employed to analyze the life and damage of low cyclic fatigue of turbine rotor. In this paper,the transient temperature and thermal stress fields of 600MW turbine under typical cold start and sliding parameter stop operations are calculated by applying finite element method. In the thermal stress analysis, the elastic-plastic finite element method is employed. Linear accumulation theory and a nonlinear continuous damage model are respectively employed to calculate the low cycle fatigue damages caused by thermal stress. The compare of these two method results show that for the Linear Damage Accumulation theory widely used in d in present engineering life assessment is under uniaxial assumption and the effects of multiaxial stress are not taken into account, the turbine rotor life is overestimate in life prediction. Not only the effects of complex multiaxial stress are taken into account but also the nonlinear accumulation process of low cycle fatigue damage is described correctly in the nonlinear continuous damage mechanics model. Therefore, the results from nonlinear continuous damage mechanics model are in better agreement with the facts than the results from linear accumulation theory.

关 键 词：汽轮机 转子 低调疲劳分析 非线性连续损伤模型 

分 类 号：TK263.61[动力工程及工程热物理—动力机械及工程]