考虑材料各向异性的纤维增强聚合物基复合材料板损伤Lamb波检测和定位

摘要

Ultrasonic Lamb wave method is a common method to detect the damage of fiber reinforced plastics (FRP) plate.However, the anisotropy material property of FRP will have a great effect on the accuracy of damage location based on lamb wave method.In order to solve this problem, a time probability density method was proposed.The method is developed from traditional ellipse method and it considers the anisotropy property of FRP material.By taking account of the group velocity variation of A0 mode waves with different propagation directions, this method calculated the travel time of the reflection wave with any damage on FRP plate, and the time flight diagram could be obtained.By establishing the mapping relationship between the time of flight and the travel time of the actual damage reflected wave, a time probability density map could be obtained to characterize the probability of the existence of the damage.The result from numerical analysis and experimental study shows that the damage location error of this method can be reduced by more than 70％ compared with that of the traditional ellipse method.This paper demonstrates the feasibility and accuracy of this method for the damage location of anisotropic FRP plates.%超声Lamb波法是检测板状结构损伤的常用方法,然而纤维增强聚合物基复合材料(Fiber reinforced plastics, FRP)本身的各向异性会对Lamb波损伤定位的精度造成较大的影响.为了解决此问题,在传统椭圆法的基础上,提出了考虑材料各向异性的时间概率密度法的损伤定位方法.该方法通过考虑不同传播方向的A0模态波的群速度变化,计算FRP板上任意一点存在损伤的反射波的走时,得到声波传播时间图.创建声波传播时间与实际损伤反射波走时的映射关系,可得到能表征损伤存在概率的时间概率密度图,通过相应的数值分析和实验研究,发现本方法误差比传统椭圆法误差的减小率可达到70％以上,论证本方法对各向异性FRP板损伤定位的可行性和准确性.