考虑弯曲和轴向振动模态的一维梁压电阻抗模型及试验研究

同时考虑一维梁结构的弯曲和轴向振动,对其压电阻抗模型进行建模分析和试验验证。在0.02～42 kHz频段内区分并标记了一维钢梁弯曲振动模态前18阶及轴向振动模态前3阶。结果表明:在0.02～7.5kHz频段内,数值计算和试验结果中谐振峰对应频率的相对误差较大:11.7%～16.5%,其原因可能是低频时振动能量较低且波的传播受结构阻尼、边界条件及环境噪音等因素影响较为明显;在7.5～42kHz范围内,两者谐振峰位置符合良好,相对误差较小:0.11%～2.31%,表明该模型在高频段具有较好的适用性;轴向振动模态对应频率大于弯曲振动模态。本研究为结构健康监测过程中检测频段的选取及损伤信息的提取提供参考。

Electro-mechanical impedance model of one-dimensional beam and experimental research considering both flexural and axial vibration modes

The theoretical analysis and experimental verification of electro-mechanical impedance model for one-dimensional beam are presented in this study. Both flexural and axial vibrations are considered in the model. In the frequency range of 0.02~42 kHz, 18 flexural vibration modes and 3 axial vibration modes of one-dimensional steel beam were distinguished and marked. Results show that in the range of 0.02~7.5 kHz, the relative error of resonance peak frequency between the predicted and experiment impedance spectra is 11.7%~16.5%. The possible reason is that vibration energy is lower in this frequency range and the propagation of wave is obviously influenced by the structural damping, boundary condition, and background noise. While in the frequency range of 7.5~42 kHz, the locations of resonance peaks are close to each other and the relative error is 0.11%~2.31%. This shows that the model has a better application in the higher frequency range. Moreover, the axial vibration modes are larger than those flexural vibration modes. The results would provide a good reference for the frequency band selection and damage information extraction during the procedure of structural health monitoring with EMI technique.