Modeling And Simulation Analysis Of Blade Side Milling Coupled Chatter And Deformation

Turbine is a kind of energy conversion machine which is widely used in aviation,aerospace,navigation,automobile,construction machinery,generator set and other fields.And the impeller is the key part of the turbine,which plays the role of energy conversion.The impeller is a kind of complicated part,which is difficult to manufacture.Blades of impellers are generally thinner and less rigid,which are prone to chatter and large cutting deformation in the process of machining.However,chatter will increase the cutting force in the cutting process,further increase the deformation generated in the cutting,and affect the surface quality of impeller blades and machining accuracy.In this thesis,the chatter and deformation of impeller blades in the machining process are modeled and simulated,and the coupling model of chatter and deformation is established to study the influence of flutter on the cutting deformation and manufacture accuracy in the cutting process.Firstly,the dynamic cutting thickness model of regenerative chatter theory is improved,and the cutting force model of end mill side milling is established.The impeller blade is simplified into a rectangular cantilever beam structure with fixed end constraints.The simplified blade deformation model is decomposed into bending deformation model and torsional deformation model when analyzing the blade side milling deformation.Bending deformation is analyzed according to the theory of material mechanics.Torsional deformation is a typical constrained torsion of bar.In this way,the chatter and deformation are coupled,and the side milling deformation model of the coupled chatter factor is established.The simplified blade model of axial flow impeller is simulated and solved.Aiming at the simplified axial flow impeller blade,the stiffness curve of corresponding axial cutting depth was firstly extracted by using finite element method,so as to facilitate the subsequent simulation.Aiming at regenerative chatter using Runge-Kutta method,the chatter time domain simulation is carried out,and the cutting force model is solved,then the cutting forces with different parameters and different cutting states are obtained.In the process of deformation simulation,the cutting force obtained from the cutting force model is taken as the input,and the load is applied according to the set loading rules to simulate the actual cutting process,and the deformation,spring back and plastic deformation of the blade are obtained.The phase cutting experiment is carried out to verify the reasonability of cutting force model and deformation simulation.The simulation solution of radial-flow impeller blade is presented.The simulation solution of radial flow impeller blade is presented.For the simulation of radial flow impeller blade,the stiffness curve and the axial cutting depth curve are firstly extracted.Taper ball head milling cutter is used in machining impeller,and the model of opposite milling cutter is modified.Then,flutter simulation is carried out on the suction surface of impeller,cutting force is obtained by solving the cutting force model,and deformation simulation of coupled flutter factors is carried out according to the same deformation simulation parameters,and the phenomena of cutting deformation,spring back and plastic deformation in the process of side milling are analyzed.Experiments are carried out for different cutting parameters to verify the rationality of the flutter deformation coupling model.