Experimental Analysis And Numerical Calculation Method Research On Dynamic Parameters Of Magnesium Alloy

The problems of vibration and noise reduction in aviation,aerospace and other fields have received increasing attention from academia.Magnesium alloy materials are widely used in aviation and aerospace fields due to their high damping properties,low density,high specific strength and large specific modulus of elasticity.Therefore,it is necessary to carry out the research on dynamic parameter characteristics of magnesium alloy.In this paper,based on experimental methods,the dynamic parameters such as elastic modulus,Poisson’s ratio,and the damping capacity of a certain type of magnesium alloy were studied,and the changing mechanism of these parameters,especially the damping parameters,on service environment and excitation load is revealed.The damping parameter is defined as a dynamic parameter that changes with certain factors.Based on the evolution of the damping parameter,a random dynamic analysis method is proposed based on the pseudo excitation method,and the fatigue performance of the magnesium alloy were explored in the end.The research in this paper provides a certain reference for the application of magnesium alloy materials in aerospace and other fields.The main work of this paper are as follows:(1)The statics parameters such as elastic modulus,density and Poisson’s ratio of a certain type of magnesium alloy materials were measured by using the tensile method and drainage method.The dynamic mechanical analyzer(DMA)was used to investigate the variation law of the material damping parameters of this type of magnesium alloy with the service environment and the excitation load;the forced resonance method was used to study the effect of the material scale on the damping performance.The results were verified by numerical analysis and experimental data.(2)Analyze the similarities and differences of the dynamic system using constant damping and variable damping from the dynamic mechanism.Based on the principle of the pseudo excitation method,a numerical analysis method of stochastic dynamics with damping-time-varying is established.Using ABAQUS software,based on the measurement of magnesium alloy material parameters,the dynamic responseof the magnesium alloy engineering support under sinusoidal excitation and random excitation was calculated,which confirmed that the different of dynamic response of the constant damping system and the variable damping system cannot be ignored.(3)The fatigue properties of magnesium alloy bearings and aluminum alloys bearings which have the same configuration were investigated.According to the S-N curve of the material and the acceleration power spectral density function(PSD)of the random vibration,the ABAQUS software and MSC.Fatigue software were used to calculate the location of cracks in the structure and the fatigue life of the structure.