Dynamic Modeling And Simulation Of The Functionally Grade Materials Flexible Blade

The blade is an important work component of the engine,and its mechanical characteristics are related to the performance and efficiency of the engine.Therefore,it is necessary to study its dynamic behavior.The blade is in a severe working environment with high temperature and high speed.At the same time,during the work process,high-speed and large-scale rotary motion will inevitably cause damping.These are the key considerations for blade dynamics research.In this paper,the engine blade is abstracted as a simplified mechanical model of a central rigid body-flexible beam,functionally graded material?FGM?with strong heat resistance is selected,the large-scale rotation of the blade is considered,and the problems existing in the above blade work are driven Modeling analysis.The main research contents are as follows:Firstly,the mechanical model of the blade rotation center rigid body-FGM flexible beam is mechanically modeled,the deformation field is described by the hypothetical modal method,the dynamic equations are derived using the Lagrange equation of the second type,and the C++simulation software is compiled to compare the primary models.The difference with the zero-order model.Analyze the dynamic characteristics of the flexible beam during large-scale rotation,explain the cause of the functional gradient distribution-vibration deviation,and point out the offset term K₂ and the factors affecting the vibration deviation.Based on the constant rotation angular velocity,the natural frequencies of transverse bending of two functional gradient distributions are analyzed.Secondly,the dynamic model of the variable cross-section solid flexible beam and the variable cross-section hollow flexible beam are established separately according to the actual blade model,and the effects of the cross-sectional change rate,volume and hollow configuration on the dynamic behavior of the flexible beam are explored through the simulation results.It provides a theoretical reference for the design of blade models in actual engineering.Thirdly,the influence of thermal environment is added the dynamic model,and the one-dimensional thermal steady-state equation is used to solve the temperature field distribution law.Then the thermal strain is taken into account in the constitutive relationship and combined with the Lagrange equation of the second kind to obtain the rigid-flexible thermal coupling dynamic equation.Consider the two working conditions of unilateral heating and double heating,and then analyze the dynamic characteristics of the system under the two working conditions.Finally,two kinds of damping?viscous damping and square damping?generated by wind resistance are introduced into the dynamic model,and the damping matrix and the rigid-flexible coupling dynamic equation are combined to form a system dynamic equation considering the damping effect,and the damping characteristics are analyzed And the influence of factors such as functional index under damping on blade dynamic behavior.On this basis,it combines with the thermal environment to form a dynamic equation closer to the actual,which provides a reference for studying the dynamic behavior of the engine blade.