Research On Experimental And Numerical Simulation Of Foreign Object Damage To Titanium Alloy Blades

Foreign Object Damage （FOD）of aircraft engine fan/compressor blades is an accident oftenoccurs in the process of aircraft taking off or landing. Stress concentration and microscopic damagecaused by FOD makes it very easy for the blade under vibration loading occurring High Cycle Fatiguefailure.It is of great significance of adopting the method of experimental and numerical simulation toconduct study of FOD to fully disclose FOD characteristics and deepen the research work on theinfluence of the HCF performance of blades.Study of FOD to TC4titanium alloy in this thesis isfocused mainly in the following aspects:(1)Ballistic impact of TC4alloy simulated blades is done based on a gas gun.Damage causedby impact is characterized macroscopically and microcosmically. The result shows that the impactdamage size is closely related to impact energy,the primary failure mode of TC4alloy is adiabaticshear plugging failure when it is subjected to high-speed steel ball impact,adiabatic shear bandgenerates in the vicinity of the notch and high levels of tensile residual stress exits around the notch.(2)Uniaxial deformation behavior of TC4alloy under quasi-static loading and dynamic loadingis studied experimentally and the ture stress-strain curve is acquired. Eighteen material parameters inthe constitutive part of the Bammann material model are fitted based on the experiment data. Theresults indicates that plastic flow behavior of TC4is sensitive to strain rate and temperature.Stresstriaxiality has significant effect on the equivalent plastic strain to fracture of TC4.Bammann modelcorrelates TC4deformation data and predicts the failure behavior of notch samples under quasi-staticloading well.（3）Numerical simulation methods for FOD events based on Bammann material model areverified by impact tests.The results indicates that impact damage from hard body to TC4blades canbe numerical simulated macroscopically and microcosmically with reasonable accuracy by themethod developed and the localization of plastic deformation and adiabatic shear plugging failurephenomenon can be simulated when fine meshing finite element model is used.