功能梯度经典梁损伤识别模态应变能变化率法的抗噪音性能研究

A STUDY OF ANTI-NOISE PROPERTIES OF MODAL STRAIN ENERGY CHANGE RATIO METHOD FOR THE DAMAGE IDENTIFICATION OF FUNCTIONALLY GRADED CLASSICAL BEAM

针对功能梯度经典梁,研究损伤识别的模态应变能变化率方法的抗噪音性能。基于有限元商用软件ABAQUS计算平台,计算功能梯度经典梁自由振动模态参数,并加入一定水平的噪音。用这些含噪音的模态参数仿真实际测量值。模态参数测量噪音模型采用高斯分布模型,并比较了计算噪音水平的三种计算方法。通过数值算例,分析测量噪音对功能梯度经典梁损伤识别的影响。从损伤识别结果可以发现,在1%、2%和5%的噪音水平情况下,均能很好地识别出梁的损伤单元。这表明功能梯度经典梁损伤识别的模态应变能变化率方法具有良好的抗噪音性能。

The anti-noise property of modal strain energy change ratio method is studied for the functionally graded classical beam. Based on the computing platform of the finite element method, commercial software ABAQUS,modal parameters are computed for the free vibration of functionally graded classical beam. Those modal parameters are directly added by Gauss noises with a certain level in order to simulate the measured modal parameters. Three methods are compared for the computation of noise levels. Numerical examples are given to analyze the noise effect on the damage identification results. Numerical results reveal that the damaged element can be successfully identified with 1%, 2% or 5% measurement noise. It means that the modal strain energy change ratio method has very good anti-noise property for identifying damage in the functionally graded classical beam.