Research On Energy Dissipation Mechanism Of Graphyne Nanostructures

As a new member of the carbon-based nanostructure,graphyne is considered to be a suitable material for manufacturing nanoscale mechanical resonators due to its excellent mechanical,electrical and optical properties.The quality factor Q is an important standard to measure the performance of nano-scale mechanical resonators.Higher Q factors mean lower energy consumption,higher sensitivity and better reliability.According to sources,damping factors that affect the Q factor can be divided into two categories: external damping and internal damping.External damping includes fluid damping,clamp damping and surface dissipation,etc.The influence of external damping on Q factor can be greatly eliminated by carefully designing the geometric shape and working environment of nanostructures.Internal damping mainly include thermoelastic damping and Akhiezer damping,minimize the stress gradient inside the resonance structure through design,can reduce the thermoelastic damping structure influence on the Q factor,but as more Akhiezer damping nature of damping factor and give resonator Q factor to set up a basic limit,so the graphite acetylene Akhiezer damping mechanism of nanostructures,the certificate of graphite acetylene nanostructures dissipation a nd improve the Q factor of nano mechanical resonator has a good sense.The main research contents of this paper are as follows:Firstly,the characteristics of graphyne nanostructure are introduced,then the generation mechanism of Akhiezer damping is explained in detail,and the calculation theory of Akhiezer damping is summarized,and the expression of Akhiezer damping Q factor is given through formula derivation.Then based on the Akhiezer damping theory,non-equilibrium molecular dynamics method is used to simulate the Akhiezer damping of graphyne nanostructures.The numerical values of tensile stiffness and structural reference tension of graphyne nanostructures are determined by simple tensile calculation of the nanostructures,and the fact that the existence of acetylene bonds between aryl groups leads to structural softening is verified.Through periodic stretching of graphyne nanostructure under certain forced frequencies,the numerical values of Q factor of graphyne nanostructure under different forced frequencies were calculated.It was found that the numerical values of Q factor tended to decrease with the increase of forced frequencies while the model remained unchanged.For this phenomenon,we introduce the theoretical formula to explai n.Then we have different between the aryl acetylene key number of graphyne nanostructure model in the Q factor under the same forced frequency calculation,the results show that as the Q factor between with aryl acetylene decreases with the increase of the number of keys,we from aryl acetylene key caused the structure between the softening point of view of the now explained why.Finally,the continuum mechanical model of Akhiezer damping of graphyne nanostructure is introduced.Firstly,the theoretical model of Akhiezer damping of graphyne nanostructure is deduced and the mechanical expression of continuum is given.Combined with the results of theoretical derivation,the specific steps of the necessary parameters to describe Akhiezer damping,such as Gruneisen parameters and phonon relaxation time,are given.Within the graphyne nanostructures on applying different plane strain and fixed end stretching relaxat ion after strain,by calculating different outside under the plane strain in flat vibration modal frequency Gruneisen parameters is given and phonon relaxation time,describe the necessary Akhiezer damping parameters,such as to obtain parameters into the expression of continuum mechanics can make a comparison with the results of molecular dynamics simulation.