Random Vibration Analysis Of Laminated Composite Plates Subjected To Turbulent Boundary Layer Excitations

Space vehicles,such as launch vehicles,missiles and airplanes,are subjected to the turbulent boundary layer during operation.Under the turbulent boundary layer,the vibration and sound radiation generated by these aircraft structures not only cause local fatigue damage to the structure,but also interfere with equipment or passengers inside the aircraft,thereby greatly reducing the safety,reliability and comfort of the entire system.As composite material with high specific strength,high stiffness,high temperature resistance,corrosion resistance,designable and a series of advantages,has been widely used in aerospace vehicles.Therefore,the study on the random vibration analysis of composite structures under turbulent boundary layer has important theoretical significance and application value.This paper studies the random vibration problem of composite laminates under turbulent boundary layer.First,the advantages and disadvantages of the analytical solutions of the three laminated composite laminates are compared.Then the static and dynamic problems of laminate are solved based on the laminates which are constructed by the first order shear deformation theory and the Reddy high order shear deformation theory,and the virtual excitation method is applied to the laminates.At last,the Fourier series is used to expand the cross power spectral density function of the turbulent boundary layer,and then the problem of the turbulent boundary layer of the composite laminates is converted to the response of the deterministic harmonic pressure field.The specific work is as follows:1)Comparison of the theory of three kinds of composite laminates.At present,the theory of composite laminates is divided into three categories: the first kind is the equivalent monolayer theory,including the classical laminate theory,the first order shear deformation theory and the high order shear deformation theory;the second kind is the three-dimensional elastic theory,including the Layerwise theory and the traditional three-dimensional elastic theory;the third is the global-local theory,and the typical one is a global-local 1,2-3 high order theory.Each theory has different accuracy and computational efficiency in computing different physical quantities,such as deflection or natural frequency.Through numerical examples,the first order shear deformation and the Reddy high order shear deformation theory have high efficiency.Therefore,these two theories are used as the laminates theory for subsequent research.2)Finite element static and dynamic analysis.Based on the first order shear deformation theory and the Reddy type high order shear deformation theory,the results of static,vibration frequency and steady state response are calculated,and the random vibration response of composite laminates is analyzed by the pseudo excitation method.3)Stochastic dynamic analysis under turbulent boundary layer excitation.In this paper,the Fourier series is used to expand the cross power spectral density function of the turbulent boundary layer,and then the problem of the turbulent boundary layer of the composite laminates is converted to the response of the deterministic harmonic pressure field...