抽水蓄能电站钢岔管水压试验结构应力测试分析与评价

Structural stress test analysis and evaluation of steel bifurcated pipe in pumped storage power station

为检验钢岔管设计的合理性和施工的可靠性,采用应变电测法对钢岔管水压试验过程进行结构应力测试,掌握钢岔管关键应力控制点的应力分布情况;采用有限元法对钢岔管水压试验工况进行结构应力分析,确定该工况下关键应力控制点的抗力限值及应力分布情况。测试数据表明:测试应力值与试验压力呈良好的线性正相关关系,钢岔管管壁最大应力值与试验压力值的相关系数R为0.999988,钢岔管月牙肋最大应力值与试验压力值的相关系数R为0.999896,良好的线性关系表明应变计的防护安全可靠,测试系统稳定。基于形状改变比能理论,对测试应力值进行等效处理,转换为Von Mises等效应力值。对比分析测试数据和计算成果:钢岔管水压试验结构最大应力值均小于结构的抗力限值,结构强度满足设计要求。管壁最大应力值位于靠近肋板端部的主管折角处(公切球半径最大部位),月牙肋最大应力值位于月牙肋内侧中部位置,与计算结果吻合,符合钢岔管的结构特性。Von Mises等效应力值与设计计算值最小相差-9.4%,吻合度较高。

In order to verify the rationality of the design and reliability of the construction of the steel bifurcated pipe,the stress distribution of the key stress control points of the steel bifurcated pipe was measured by the strain electric method during the hydraulic test process.The finite element method was used to analyze the structural stress of steel bifurcated pipe under the condition of hydraulic test.The resistance limit and stress distribution of the key stress control points were determined.The test data showed that there was a good linear positive correlation between the test stress and the test pressure.The correlation coefficientRbetween the maximum stress value of the steel bifurcated pipe wall and the test pressure value was 0.999988.The correlation coefficientRbetween the maximum stress value of the crescent rib of the steel bifurcation pipe and the test pressure value was 0.998996.The good linear relationship indicated that the protection of the strain gauge was safe and reliable,and the test system was stable.Based on the theory of shape change specific energy,the test stress value was equivalently processed and converted into Von Mises equivalent stress value.Through the comparative analysis of the test data and the calculation results,the maximum stress value of the structure in the hydraulic test of the steel bifurcated pipe was less than the resistance limit value of the structure,and the structural strength met the design requirements.The maximum stress value of the pipe wall was located at the corner of the main pipe near the end of the rib(the largest radius of the tangent sphere),and the maximum stress value of the crescent rib was located in the middle of the inner side of the crescent rib,which was consistent with the calculation results and conformed to the structural characteristics of the steel bifurcated pipe.The minimum difference between the Von Mises equivalent stress value and the design calculation value was-9.4%,which showed a high degree of agreement.