压力容器接管区模拟异形试板的拟协调元分析

Analysis of simulating special-shaped plates at the pressure vessel nozzle by the quasi-conforming element method

针对压力容器接管区高峰应变的特征,在压力容器接管模拟试板的基础上,对多种孔径的异型板应力应变场应用拟协调条件,建立单元间位移弱连续条件的拟协调有限元模型。该模型不需要应力满足平衡条件,简化了矩阵求逆计算,容易得出应变的离散精度,因此可以解决常规有限元难以适应的奇异性领域。文章分别就不带裂纹和带有裂纹的异型板进行应力数值分析,计算结果表明高峰应变区的应力集中与试验结果较为吻合,为压力容器接管部位的设计和裂纹疲劳扩展分析提供了可靠依据。

The simulating special-shaped plates at pressure vessel nozzle are studied,and in view of the characteristic of high strain gradients at the junction between the pressure vessel and the nozzle, quasi-conforming element models are established for two types of special-shaped plates, which satisfy weak continuous conditions between elements. It is not necessary for the quasi-conforming element models to satisfy stress equilibrium conditions, so the calculating process of matrix＇s inversion is simplified,and the discrete precision can be predicted easily. The stresses are obtained by means of the quasi-conforming element method. The calculation results are in accordance with those of experiment. This paper provides a basis for the design of special-shaped plates and analysis of fatigue crack propagation.