基于内聚力模型的汽轮机末级叶片涂层裂纹扩展数值模拟  

Numerical Simulation of Crack Propagation in Coating of Last Stage Blade of Steam Turbine Based on Cohesive Zone Model

作　　者：孙长青[1] 方镜森 王超[1] 张小辉[1] SUN Chang-qing;FANG Jing-sen;WANG Chao;ZHANG Xiao-hui(Shenyang Institute of Engineering,Shenyang 110136,China)

机构地区：[1]沈阳工程学院,沈阳110136

出　　处：《汽轮机技术》2024年第2期156-160,共5页Turbine Technology

基　　金：辽宁省教育厅基本科研项目(LJKZ1087);辽宁省高校创新人才专项计划项目(LR2020089)。

摘　　要：为探究汽轮机末级叶片基体与涂层结合强度和分析涂层裂纹萌生及扩展规律,基于双线性内聚力模型理论,建立了基体-涂层界面裂纹扩展计算力学模型,采用有限元仿真方法模拟了汽轮机末级叶片熔覆涂层脱落情况。结果表明,涂层和基体材料参数会影响涂层脱落时的裂纹扩展规律和力学响应;适当增大基体材料弹性模量和减小涂层材料弹性模量能延缓水蚀过程中涂层的失效时间;增大涂层和基体材料弹性模量,能提高涂层与基体结合界面在裂纹扩展中所能承受的最大应力,进而提升涂层与基体结合界面的耐冲击能力。In order to explore the bonding strength between the substrate and the coating of the last stage blade of steam turbine and analyze the crack initiation and propagation law of the coating,based on the bilinear cohesive zone model theory,a mechanical model for calculating the crack propagation at the substrate-coating interface was established.The finite element simulation method was used to simulate the shedding of the cladding coating of the last stage blade of steam turbine.The results show that the material parameters of the coating and the substrate will affect the crack propagation law and mechanical response when the coating falls off.Appropriately increasing the elastic modulus of the substrate material and reducing the elastic modulus of the coating material can delay the failure time of the coating during the water erosion process;increasing the elastic modulus of the coating and the substrate material can increase the maximum stress that the coating-substrate bonding interface can withstand during crack propagation,thereby improving the impact resistance of the coating-substrate bonding interface.

关 键 词：内聚力模型 数值模拟 有限元 结合强度 

分 类 号：TG174.4[金属学及工艺—金属表面处理] TK225[金属学及工艺—金属学]