Research On Analysis Method For Blade Fracture Speed Of Power Turbine

In view of calculation method of aero-engine power turbine blade fracture speed,the quasi-static tensile tests of smooth round bar specimens and notched specimens were carried out with the typical materials of aero-engine turbine—K438 and K424—selected.The specimen fractures were observed by SEM to analyze the failure mode.The constitutive model of K424 was fitted based on the tensile response curve of smooth specimen and was optimized based on the tensile response of notched specimen.The tensile response curves of K424 notched specimens were predicted by large deformation finite element analysis method.The results show that the notched tensile response curves can be well predicted by the optimized constitutive model.A continuum damage mechanics model based on plastic strain was established.The corresponding model parameters were determined and were used to predict the tensile response curves of the notched specimens based on this model.The results show that the fracture strains of the notched specimens can be well predicted by continuum damage mechanics model.The tensile test of a blade specimen designed was carried out to obtain the limit tensile load.The limit tensile load of blade tensile specimen was predicted by traditional finite element analysis method and by the large deformation finite element method based on continuum damage mechanics model.The results show that the limit tensile load of blade specimen can be well predicted by traditional large deformation finite element method and by continuum damage mechanics model both.And the continuum damage mechanics model can be further used to estimated tensile fracture failure mode of the blade specimen.