Damping Characteristics And Parameter Optimization Analysis Of Fractional Viscoelastic Oscillator System

Due to the particularity of its working environment,engineering vehicles produce a lot of vibration and noise,which bring harm to the vehicle itself and the driver’s body and mind.It is found that viscoelastic materials as damping materials can play a good cushioning and damping effect,at the same time,because of its low production cost and simple structure,it is widely used in engineering vehicle vibration reduction.Compared with integer order modeling,fractional order modeling can better describe the damping characteristics of viscoelastic materials,so fractional order viscoelastic vibration subsystem is taken as the research object.According to the constitutive relation of viscoelastic materials,three kinds of systems KFVEO,MFVEO and SFVEO were obtained by modeling Kelvin-Voight fractional viscoelastic oscillator with solid properties,Maxwell fractional viscoelastic oscillator with fluid properties and standard linear solid(SLS)fractional viscoelastic oscillator.Since there are still some difficulties in solving fractional differential equations,the numerical solutions of three kinds of fractional system models are studied here,and the numerical solutions of three kinds of vibration subsystem models in discrete state are obtained by using the closed algorithm.The dynamic responses of three fractional viscoelastic oscillator system under sinusoidal excitation and unit impulse excitation are calculated,and then the influence of stiffness-damping parameters of viscoelastic oscillator system on the damping characteristics of the system is analyzed.In order to optimize the parameters better,a surrogate model optimization strategy is proposed to optimize the parameters of the fractional viscoelastic oscillator model.Considering the complexity of fractional order model optimization,Kriging model and quadratic response surface model are used to surrogate the displacement response function of three fractional order viscoelastic oscillator systems,thus reducing the complexity of optimization calculation.The results show that the quadratic response surface surrogate model can achieve higher precision by using fewer sample points,and has better surrogate effect on fractional order model than Kriging model.Through the analysis of the influence of system parameters on the system damping,optimize the system parameters of high sensitive degree,selecting the system natural frequency ω_n,damping(?)ratio,order α and the shape parameters(?)as design variables,from the constitutive relation of viscoelastic material and the dynamic relation of fractional viscoelastic system,the hysteretic ring area which can reflect the stress-strain relation of material and the displacement response of oscillator system under sinusoidal excitation are selected as the optimization objectives,and then the multi-objective optimization problem is constructed.Finally,used the multi-objective genetic algorithm to solve the multi-objective optimization problem,and the optimal parameter matching strategy is obtained.