基于多温度SDFF模型的反应堆压力容器钢韧脆转变区韧性评价  

Toughness Evaluation in Ductile-to-Brittle Region of Reactor Pressure Vessel Steel Based on Multi-temperature SDFF Model

作　　者：李国强 俞海兵 巫元俊 LI Guoqiang;YU Haibing;WU Yuanjun(Guangxi Fangchenggang Nuclear Power Co.,Ltd.,Fangchenggang 538001,China;Applied Mechanics and Structure Safety Key Laboratory of Sichuan Province,School of Mechanics and Aerospace Engineering,Southwest Jiaotong University,Chengdu 610031,China)

机构地区：[1]广西防城港核电有限公司,防城港538001 [2]西南交通大学力学与航空航天学院,应用力学与结构安全四川省重点实验室,成都610031

出　　处：《机械工程材料》2024年第11期111-118,共8页Materials For Mechanical Engineering

摘　　要：采用最大似然估计法对局部断裂失效概率(SDFF)模型的参数标定进行改进,建立可通过不同温度下的断裂韧性试验数据标定模型参数的多温度SDFF模型,使用由反应堆压力容器(RPV)钢制成的1英寸(25.4 mm)厚紧凑拉伸试样(1T CT试样)和0.5英寸厚紧凑拉伸试样(0.5T CT试样)的低温断裂韧性试验结果求解模型参数,预测了这2种试样的韧脆转变温度,并对二者的断裂韧度下边界曲线进行了分析。结果表明:多温度SDFF模型计算得到的0.5T CT试样和1T CT试样的韧脆转变温度分别在−81℃和−64℃,与试验结果吻合良好,相对误差在6%左右;在温度−90~20℃下所测断裂韧度数据均落在失效概率5%包络线至95%包络线内,该模型在−90℃至常温范围内对不同尺寸的试样均具有良好的适应性。采用0.5T CT试样对材料韧脆转变区断裂韧性进行分析时,以其多温度SDFF模型5%断裂失效概率曲线作为断裂韧度下边界曲线能够涵盖0.5T CT试样和1T CT试样的所有试验数据,且裕量较小,以1%断裂失效概率曲线为断裂韧度下边界曲线的裕量较大。The parameter calibration for a strain-energy-density-based fracture failure(SDFF)model was improved by a maximum likelihood estimation method,and the multi-temperature SDFF model whose parameters could be calibrated by the fracture toughness test data at different temperatures was established.The model parameters were calculated with low-temperature fracture toughness test results of a one-inch thick compact tension(1T CT)specimen and a 0.5-inch thick compact tension(0.5T CT)specimen sampled from reactor pressure vessel(RPV)steel.The ductilebrittle transition temperatures of the two specimens were predicted,and the lower boundary lines of fracture toughness were analyzed.The results show that the ductile-to-brittle transition temperatures of the 0.5T CT specimen and 1T CT specimen calculated by the multi-temperature SDFF model were−81℃and−64℃,respectively,and the calculated results were in good agreement with the test results with a relative error about 6%.The fracture toughness data measured at−90℃to 20℃were all within the 5%to 95%failure probability envelope,and the model had good adaptability to specimens of different size from−90℃to normal temperature.When the 0.5T CT specimen was used to analyze the fracture toughness of the material in the ductile-brittle transition zone,with whose 5%fracture failure probability curve as the lower boundary line of fracture toughness could cover all the test data of 0.5T CT specimen and 1T CT specimen,and the margin was small;the margin with the 1%fracture failure probability curve as the lower boundary line of fracture toughness was larger.

关 键 词：RPV钢 韧脆转变区 最大似然估计 SDFF模型 断裂韧性 

分 类 号：TL341[核科学技术—核技术及应用]