论文部分内容阅读
为了研究材料微观特性对结构疲劳寿命的影响,根据Tanaka-Mura疲劳裂纹萌生寿命计算理论,模拟某镍基粉末合金涡轮盘喉道表面疲劳裂纹萌生寿命。利用泰森多边形生成法,模拟微观多晶结构,建立宏-细观模型相结合的三维仿真模型。实现3项关键技术:1)在三维模型中模拟了面心立方晶体中{111}面族的12条主滑移系;2)应用缺口根部裂纹萌生的Tanaka-Mura理论模型模拟一条微裂纹在另一条裂纹尖端萌生;3)模拟了微裂纹的起裂、扩展与联合过程,最终形成一条宏观裂纹。对某表面带刀痕涡轮盘疲劳裂纹萌生寿命数值仿真结果与真盘试验结果相差20%。研究表明,减小晶粒尺寸、降低表面粗糙度、形成表面压缩残余应变以及析出沉淀颗粒都有利于提高涡轮盘的疲劳裂纹萌生寿命。
In order to study the effect of material microstructure on fatigue life of structure, fatigue life of fatigue crack initiation on a nickel-base powder alloy turbine disk throat was simulated according to Tanaka-Mura fatigue crack initiation life calculation theory. Using the method of Tyson polygons to simulate microscopic polycrystalline structure, a three-dimensional simulation model combining macroscopic and mesoscopic models is established. Three key technologies are achieved: 1) 12 main slip systems of {111} family of face-centered cubic crystals are modeled in 3D model; 2) Tanaka-Mura theoretical model of gap root initiation is used to simulate a Another crack tip initiation; 3) simulation of micro-crack initiation, expansion and joint process, the final formation of a macro-crack. The numerical simulation results of the fatigue crack initiation life of a turbo disk with a blade on a certain surface are 20% different from the real disk test results. The research shows that reducing the grain size, reducing the surface roughness, forming the surface residual compressive strain and precipitating the precipitated particles all contribute to the improvement of the fatigue crack initiation life of the turbine disk.