Analysis Of Thermal Elastic Attenuation Characteristics Of Nanometer Resonators

Nanostructures components with its unique physical,mechanical and electrical performance,is now widely used in many industrial and research fields than macro fields,and the most way to used is their resonance.Because of the energy produced by resonator in vibration inevitably translate into heat dissipation to the outside world,which will resulting in energy attenuation.Generally we use thermoelastic damping to characterization of nano resonator energy attenuation by degree of one cycle.Analysis of the problem of thermoelastic damping using generalized thermoelastic theory by considering a relaxation time,which believed that the propagation speed of heat in the nanometer rod is limited.This paper,by means of molecular dynamics simulation,we consider the resonator sensor components as a nano rod,to analyze the impact of structure scale and the heat source temperature on the thermal relaxation time,the results indicate that thermal relaxation time are the basic parameters of nano rod,not changes with the change of the structure dimensions and the heat source temperature.At the same time,the thermal relaxation time reference value of copper,aluminum and nickel materials is calculated.The process of energy convert to heat reflected energy attenuation.Firstly we treat the nano resonator vibration parts as nano beam.Using molecular dynamics simulation method with free boundary condition to analyzed the influence of different parameters on the nano beam thermoelastic damping.The results show that the different parameters on the thermoelastic damping will be weakened as the growth of the vibration period,when the vibration period achieve a certain value,thermoelastic damping will go down to 510-of order of magnitude.At the same time,it is found that the longer of the nanometer beam length,the less the thermal elastic attenuation will be,and vice versa.The higher the ambient temperature,the greater the thermal elastic attenuation.Keep the width of the beam unchanged,the smaller the L/ H beam,the bigger the thermal elastic damping;In addition,the thermal elastic damping of the transverse vibration of the cylindrical beam and rectangular beam is simulated,and the thermal elastic dissipation of the rectangular beam is larger than that of the cylindrical beam.Finally simulated nano beam longitudinal vibration thermoelastic damping,the results show that nano beam longitudinal vibration and the transverse thermal elastic damping vibration of the same change trend,which because transverse vibration and longitudinal vibration producing thermal elastic damping mechanism of the two modes are consistent basically.As the last,three thermal elastic damping models are summarized based on the classical theory,there are: Zener standard viscoelastic model,Lifshitz-Roukes through the method of complex frequency calculation model with exact solutions of thermoelastic damping,Ru considering the surface effect to calculate thermal elastic damping model.On the basis of such theory,the thermal elastic damping calculation model of longitudinal vibration is derived by using the method of the method.