采用应力分析法评估锅炉高温三通强度及其寿命

Evaluation of Strength and Life for Boiler Tees at Elevated Temperature by Stress Analysis Method

针对锅炉高温三通的结构特点,提出了评价其强度及寿命的有限元应力分析方法.强度评估采用应力分类原则并使用密赛斯当量应力,总体膜应力区域引入开孔减弱系数概念以避免分析模型复杂化;寿命中的疲劳损伤部分按弹性瞬态考虑,并采用应力指数法简化模型,以提高计算效率;蠕变损伤部分考虑材料的塑性及蠕变松弛作用.以一个实际锅炉三通为例,结合通用有限元软件ANSYS进行了其强度及寿命的计算,结果表明:该三通符合锅炉使用30年的预期,该方法可用于锅炉高温三通的强度及寿命计算.

Aiming at the structural feature of boiler tees at elevated temperature, a finite element stress analysis method on strength and life evaluation was proposed. Stress category methodology was adopted in the strength evaluation, and von-Mises equivalent stress was used. In the general membrane stress zone of tee, the boring weakness factor of strength was introduced to avoid complication of the analysis model. In life evaluation, fatigue damage process was considered on the basis of transient-elastic analysis, and the stress-index method was used to simplify the model so as to improve the calculating efficiency. Plastic and creep relaxation effect on the material was also considered at creep damage process. Taking a practical boiler tee as the example, the strength and life of the tee were calculated by use of finite element software ANSYS. Calculated results conform to the expected boiler life of 30 years, and the method can be used for the strength and life calculation of the boiler tee at elevated temperature.