摘要
In this report, the finite element method is applied to study the crack effect on the dynamic behavior of the turbine blade. There are four subjects reported in this paper. The first subject describes the material properties, the visual observation of the blade crack, the geometric dimensional measurement of the turbine blade. The second part will present the finite element models included single blade and a group of 6 blades. The third section will build up the full model of 60 blades. The full model will have four different types: the first type that has no crack in the blade root named “No crack”, the second type has the 126 mm2 crack area in the blade root and it is named “1 Line crack”, the 3rd type has 364 mm2 crack area in the crack root (named 2 Lines Crack), and the fourth type has 598 mm2 crack area in the root (named 3 Lines Crack). The location of crack area is modeled by applying the spring elements. The vibration frequencies for single blade and a group of 6 blades are higher without the crack in the blade root. For full model of 60 blades, the vibration frequencies are lower with the crack area in the blade root. When the crack area becomes bigger, the lower frequencies of the full blade system are observed.
In this report, the finite element method is applied to study the crack effect on the dynamic behavior of the turbine blade. There are four subjects reported in this paper. The first subject describes the material properties, the visual observation of the blade crack, the geometric dimensional measurement of the turbine blade. The second part will present the finite element models included single blade and a group of 6 blades. The third section will build up the full model of 60 blades. The full model will have four different types: the first type that has no crack in the blade root named “No crack”, the second type has the 126 mm2 crack area in the blade root and it is named “1 Line crack”, the 3rd type has 364 mm2 crack area in the crack root (named 2 Lines Crack), and the fourth type has 598 mm2 crack area in the root (named 3 Lines Crack). The location of crack area is modeled by applying the spring elements. The vibration frequencies for single blade and a group of 6 blades are higher without the crack in the blade root. For full model of 60 blades, the vibration frequencies are lower with the crack area in the blade root. When the crack area becomes bigger, the lower frequencies of the full blade system are observed.
