融合兰姆波损伤指数的碳纤维板分层缺陷成像方法

Imaging of Delamination Defects in CFRP Plates Via the Fusion of the Damage Index of Lamb Waves

摘要:

兰姆(Lamb)波在结构健康监测中具有潜在的应用价值,但有关分层损伤的研究大多局限于分层定位和精度提高,对分层尺寸测量的研究较少。研究了碳纤维复合材料板中分层缺陷尺寸对不同波长Lamb波的影响。通过有限元模拟研究了线性调频Lamb波A0模态与不同分层尺寸之间的相互作用,发现当波长大于分层尺寸时,扰动程度随分层尺寸的增大而单调增大,当波长小于分层尺寸时,扰动程度呈振荡状态的现象。借助该现象提出一种碳纤维板分层缺陷的检测方法,选用波长较大的信号作为激励,利用损伤指数刻画扰动程度,将损伤指数融入成像算法中,使成像结果能反映分层尺寸信息。

Abstract:

Lamb waves have potential applications in structural health monitoring; however, most studies on de lamination damage are limited to delamination localization and accuracy improvement, and few studies on delamina tion size measurement exist. This study investigates the effects of the delamination defect size on Lamb waves of different wavelengths in carbon fiber composite panels. The interaction between the A0 mode of linear FM Lamb waves and different delamination sizes is investigated via finite element simulation, and the degree of perturbation is found to increase monotonically with the delamination size when the wavelength is larger than the delamination size and that the degree of perturbation is in an oscillatory state when the wavelength is smaller than the delamination size. Facilitated by this phenomenon, a method is proposed to detect delamination defects in carbon fiber boards. A signal with a larger wavelength is selected as the excitation, and the damage index is used to portray the degree of disturbance. Moreover, the damage index is integrated into the imaging algorithm so that the imaging results can reflect the delamination size information.