考虑气体扩散表面应力的纳米梁非线性振动分析

Nonlinear vibration analysis of a nano-beam considering gas diffusion surface stresses

工业有毒有害气体泄漏检测存在传感器灵敏度不高、检测时间长的问题。为解决该问题,提出一种基于气体吸附应力的浓度分析方法。考虑纳米梁表面气体扩散产生的表面应力敏感效应,通过分析纳米梁非线性振动性质的变化,得到泄漏气体相关信息。以Euler-Bornoulli梁为非线性振动模型,建立考虑气体扩散表面应力的纳米梁非线性振动方程,利用多尺度方法研究气体扩散表面应力影响下的纳米梁非线性振动。通过分析幅频响应曲线,研究了扩散气体浓度、偏摩尔体积、扩散时间、阻尼、直流激励电压和交流激励电压等参数与纳米梁振动之间的关系,分析了改变参数来减弱系统非线性的方法。研究结果表明:不同的扩散气体、浓度、扩散时间会对纳米梁振动产生不同的影响,检测纳米梁的振动可以进行扩散气体信息的检测;通过改变系统参数可以降低系统的非线性振动,增强系统的稳定性。该研究工作从振动角度为检测气体浓度以及扩散速度提供一种物理检测方法和检测理论。

In the industrial toxic and harmful gas leakage detection field,the sensors usually have the disadvantages of low sensitivity and long detection time.A concentration analysis method based on gas adsorption stress was proposed to solve the problem.The surface stress sensitivity effect generated by the gas diffusion on the surface of a nano-beam was considered,and the related information of the leakage gas was obtained by analyzing the nonlinear vibration properties of the nano-beam.An Euler-Bornoulli beam was used as the nonlinear vibration model.The surface stress due to the gas diffusion was considered and the nonlinear vibration equation of the nano-beam was established.The relationships between the vibration nonlinearity of the nano-beam and the parameters such as diffusion gas concentration,partial molar volume,diffusion time,damping,DC excitation voltage and AC excitation voltage were obtained by the amplitude-frequency response analysis.Methods for changing parameters to reduce the system nonlinearity were explored.The results show that different diffusion gases,concentration and diffusion time have different effects on the nano-beam vibration,so,the vibration of the nanobeam can be measured to detect the diffused gas information.By modifying the system parameters,the nonlinear vibration of the system can be reduced and the stability of the system can be enhanced.The research work provides a physical detection method and detection theory for detecting gas concentration and diffusion speed by means of vibration analysis.