可快速精确定位CFRP板冲击损伤的等时周向轨迹法

Isochronous circumferential trajectory method for the rapid and accurate location of impact damage of CFRP plate

考虑碳纤维增强树脂基复合材料(Carbon fiber reinforced plastic,CFRP)板的纤维铺层对称性和导波传播各项异性,提出一种快速、定位精确的CFRP冲击损伤的等时周向轨迹定位方法。以损伤指数与仿真计算的方式,确定CFRP板周向导波传播速度与损伤反射波的飞行时间后,依据换能器、传感器与损伤位置之间的三角函数关系,计算既满足CFRP板中导波各个方向的传播速度又满足飞行时间的似然点。线性拟合似然点形成等时周向轨迹曲线样条,根据CFRP板的铺层对称性,镜像了轨迹曲线样条形成闭合的等时周向轨迹曲线,以三曲线交点实现损伤定位。以四点矩形阵列斜对角激励的方式进行CFRP板的冲击损伤检测实验。其实验结果表明,损伤引起损伤指数值的增幅显著,损伤反射波飞行时间可准确获得。拟合轨迹所需似然点数仅为155个,具有较小的计算量。等时周向轨迹定位法的定位误差可控,在期望误差下定位精度良好,未超出损伤区域。

The symmetry of the fiber layering and the anisotropy of the guided wave propagation of carbon fiber reinforced plastic(CFRP)plate were considered.A rapid and accurate method for locating CFRP impact damage in the isochronous circumferential trajectory method was proposed.By means of damage index and simulation calculation,the propagation velocity of guided wave around CFRP plate and the flight time of damage reflected wave were determined.According to the trigonometric function relationship between the transducer,the sensor and the damage location,the likelihood point which satisfies both the propagation velocity of guided wave in each direction and the flight time in CFRP plate was calculated.The linear fitting likelihood points formed isochronous circumferential trajectory curve spline.According to the laminated symmetry of CFRP plate,the mirrored trajectory curve spline formed a closed isochronous circumferential trajectory curve,and the damage location was realized by the intersection point of three curves.The impact damage detection experiment of CFRP plate was carried out by using a four-point rectangular array diagonally excitation method.The experimental results show that the damage index value increases significantly due to damage,and the flight time of damage reflected wave can be obtained.The number of likelihood points needed to fit the trajectory is only 155,which has a small amount of calculation.The localization error of the isochronous circumferential trajectory method is controllable,and the localization accuracy is good under the expected error,and is not beyond the damaged area.