改进型密集阵列全聚焦成像算法的碳纤维复合材料板损伤定位研究

Research on damage localization of carbon fiber composite plates based on improved dense array total focusing imaging algorithm

本文针对各向异性碳纤维复合材料板的损伤定位问题,提出改进型密集阵列全聚焦成像方法。首先,考虑碳纤维复合材料板的各向异性,通过实验分析超声导波在板中的传播特性,得到沿不同传播方向的群速度值。其次,对密集型传感器阵列的参数进行分析和优化研究,分别对不同阵列参数即阵元间距和阵元数量进行指向性函数的数值分析,优化阵列的参数,以保证阵列主瓣较窄、旁瓣较低且无栅瓣。然后,提出了一种考虑碳纤维复合材料板各向异性的改进型密集传感器阵列板结构缺陷定位算法。使用超声导波在碳纤维复合材料板中沿不同传播方向的群速度值,对全聚焦算法进行修正,并利用虚拟聚焦原理对板结构进行全聚焦成像。最后,通过布置碳纤维复合材料孔洞损伤实验,对基于密集阵列全聚焦成像方法的定位精度进行分析。实验结果表明,改进型密集阵列全聚焦成像算法的定位精度为1.00 mm,相较于使用单一群速度值,该方法在定位孔洞损伤缺陷时具有更高的精度。

In this paper,in order to solve the problem of damage localization of anisotropic carbon fiber composite plates,an improved dense array total focusing imaging method was proposed.Firstly,considering the anisotropy of the carbon fiber composite plate,the propagation characteristics of the ultrasonic guided waves in the plate were analyzed by experimental methods,and the group velocity values along different propagation directions were obtained.Secondly the parameters of the dense sensor array were analyzed and optimized,and the directional functions of different array parameters,include the spacing of array elements and the number of array elements,were numerically analyzed,and the parameters of the array were optimized to ensure that the main lobe of the array was narrow,the side lobes were low,and there was no grating lobe.Then,an improved structural defect location algorithm for dense sensor array plates considering the anisotropy of carbon fiber composite plates was proposed.The total focusing algorithm was modified by using the ultrasonic guided waves group velocity values along different propagation directions in the carbon fiber composite plate,and the total focusing imaging of the plate structure was carried out by using the virtual focusing principle.Finally,the positioning accuracy of the dense array total focus imaging method was analyzed by arranging the hole damage experiment of carbon fiber composites.The experimental results showed that the positioning accuracy of improved dense array total focusing imaging algorithm method is 1.00 mm,compared to using a single group velocity value had high accuracy in locating hole damage defects.