中文摘要：

为了了解压水堆一回路弯管内表面裂纹在流固耦合作用下的扩展状况，利用ANSYS Workbench建立了舍环向内表面裂纹弯管的流固耦合模型，在不同约束条件下对不同位置的裂纹前缘应力和应力强度因子K进行了分析。分析结果表明：只有内压作用时，流固耦合会增大裂纹前缘K与应力，而且对外弯处裂纹影响大。只有闭合弯矩时，流固耦合会减小外弯处裂纹前缘K与应力。内弯处裂纹受压应力，流固耦合会减小压应力。只有张开弯矩时，流固耦合会增大内弯处裂纹前缘K与应力。外弯处裂纹受压应力。流固耦合会增大压应力。分析结果为核电一回路含缺陷弯管的安佥挂评价提供一定的依据。

英文摘要：

In order to understand the extension of the inner surface cracks of a primary elbow in a pressurized water reactor under fluid-structure interaction, a fluid-structure interaction model of a elbow including circumferential inner surface crack is established using ANSYS Workbench in it, and the stress and the stress intensity factor of the crack front in different positions are analyzed under different constraint conditions. Calculation results show： When the elbow is only under inner pressure, FSI will increase stress and K of crack front, and the impact on crack in external bend is more large than in internal bend. When the elbow is only under the closing moment, FSI will decrease the stress and K of crack front in external bend. The crack in internal bend is under compressive stress, and FSI will decrease the compressive stress. When the elbow is only under the opening moment, FSI will increase stress and K of crack front in internal bend. The crack in external bend is under compressive stress, and FSI will increase the compressive stress. The analysis results provide a basis for the safety a~sessmertt of a primary elbow containing defects elbow in nuclear power plants.