Research And Analysis Of Dynamic Characteristics Of Micro Rotary Engine

With the demand for micro power system more and more vigorous,the micro rotary engine is gradually accepted by people because of its simple structure,small size,wide application and so on.As an important part of the propulsion system,the micro rotary engine plays an important role in the performance of the whole device.When the rotary engine runs at a high speed,the structural components are subjected to very high mechanical loads with varying degrees of direction.Therefore,the analysis of the dynamic characteristics and vibration characteristics of the rotary engine is helpful for a better understanding of the working process of the engine and more objective evaluation of the performance of the engine,and it provides a new method and theoretical basis for the improvement and research of the micro rotary engine.A multi rigid body dynamics simulation model of rotary engine is established by using ADAMS virtual prototype software,the displacement curves of the center of mass,angular velocity and angular acceleration of the main moving parts of the rotary engine are simulated and analyzed,the constraint force reaction curve and size between the main parts are obtained.The flexible body model of crankshaft is established by using ANSYS finite element software.The rigid and flexible coupling model of engine is established,and the constraint force analysis between components is analyzed.The forced vibration model of the rotary engine is established by ADAMS software,and the forced vibration of the rotor engine is simulated and analyzed.The finite element analysis software ANSYS is used to analyze the free mode and the constrained mode of the main components of the rotary engine,its natural frequencies and modal shapes are obtained.The free and restrained modes of the rotary engine are analyzed,and the natural frequencies and the modal shapes are obtained.Finally,the harmonic response of the main rotating parts of the rotary engine is analyzed,the displacement of the harmonic load and the relation between stress and frequency are obtained.The dynamic characteristics of the rotary engine and its components are analyzed systematically,the motion law of the moving parts of the rotary engine meets the design requirements,the rigid and flexible coupled multi-body model is more suitable for the actual working condition of the engine than the multi rigid body model.Vibration analysis results in a larger vibration mode of the rotor engine,and the relationship between vibration amplitude and excitation frequency is obtained.Modal analysis and harmonic response analysis are used to obtain the modal shapes under different conditions.It is found that the output of crankshaft is an active part of vibration in the whole process of vibration,therefore,it is necessary to increase the rigidity and damping of the crankshaft,reduce the vibration of the crankshaft and reduce the vibration energy to the transmission mechanism and other equipment,so as to achieve the purpose of vibration reduction and noise reduction.