金属梁结构表面微损伤的谱有限元分析

针对智能压电晶片梁结构,采用谱有限元方法,基于力电理论建立压电晶片/结构耦合系统的机电阻抗损伤评价的谱元数值模型。模型中假设采用Timoshenko梁理论,压电晶片采用Euler-Bernoulli梁理论和一维压电双向耦合理论。利用哈密顿原理得到时域中控制方程和边界条件,经FFT变换建立谱元模型,进而利用谱有限元法分析了导波的频率响应特性、导纳特性以及损伤对导纳响应的影响,数值结果与有限元结果取得较好的一致。谱有限元力电耦合模型为深入理解实际检测信号进行损伤检测和评估提供了分析依据。

Spectral Finite Element Analysis of Surface Damage on Metal Beam Structure

The spectral finite element method (SFEM) is developed to model the surface-bonded piezoelectric wafer and beam structure.The Timoshenko beam theory,the Euler-Bernoulli beam theory and linear piezoelectricity are used to model the base beam and electric-mechanical behavior of the piezoelectric wafer respectively.The governing equations are obtained in the time domain by using Hamiltons principle,and then the Spectral finite element model are formulated via the fast Fourier transform.The SFEM is used to analyze the frequency response function,admittance characteristics and the influence of damage.The high accuracy of the present SFEM is verified by a comparison with the finite element method (FEM) results.The numerical model and its calculation results provide analysis basis for damage detection and assessment of the practical detection signal.