试样尺寸对核电厂主蒸汽管道断裂韧性的影响研究  

Effect of Specimen Size on Fracture Toughness of Main Steam Lines Used in Nuclear Plant

作　　者：李铁萍[1] 田欣鹭 刘锐[1] 温爽[1] 

机构地区：[1]环境保护部核与辐射安全中心,北京100082

出　　处：《力学季刊》2016年第4期747-754,共8页Chinese Quarterly of Mechanics

基　　金：大型先进压水堆核电站国家重大科技专项(2013ZX06002001-003)

摘　　要：以某核电厂SA335材料主蒸汽管道为研究对象,首先结合SA335的断裂阻力曲线(J-R曲线)试验测量结果,提出了一种方法确定韧性金属材料裂纹扩展模型(G-T模型)中的主要微观参数:初始孔隙率0f和初始孔隙间距D;随后,在有限元计算中引入G-T模型模拟了SA335紧凑拉伸试样的断裂过程,讨论了试样尺寸对于J-R曲线的影响.结果表明:试样厚度一致时,初始裂纹长度大的试样对应偏低的断裂韧性;当试样尺寸整体缩放时,较大尺寸的试样对应偏低的断裂韧性.最后,结合实例说明了试样整体尺寸对于主蒸汽管道临界裂纹长度的影响.Ferritic alloyed steel SA335 used for main steam lines in nuclear power plant is considered here. Firstly, based on the fracture resistance curve （J-R curve） from a standard fracture toughness test, a new method is put forward to estimate the main micro-parameters, i.e., the initial void ratio j- and the initial void distance D embedded in G-T model, which is popular for simulating crack extension in ductile metals. Then, crack extension process of compact tension specimen made of SA355 steel is simulated via finite element method, by incorporating G-T model with proper micro parameters. The effect of the specimen size on the J-R curve is discussed. The results show that for the same specimen thickness, larger initial crack length corresponds to lower fracture toughness. For the same geometric ratios, larger specimen corresponds to lower fracture toughness. Finally, through computational examples, the effect of the overall specimen size on critical crack length for main steam lines is investigated.

关 键 词：主蒸汽管道 断裂韧性 G-T模型 裂纹扩展 临界裂纹长度 

分 类 号：O34[理学—固体力学]