A time-of-flight based weighted imaging method for carbon fiber reinforced plastics crack detection using ultrasound guided waves

Carbon fiber reinforced plastics (CFRP) are extensively used in aerospace, marine, and automotive fields. A variety of imaging methods for plate structures are proposed to find the damage as early as possible and ensure the safety of the structure. However, due to the anisotropy of CFRP, current methods still have some limitations for CFRP damage imaging, such as inaccurate localization, large spots and obvious artifacts. To improve the damage imaging performance of CFRP structures, a time-of-flight based weighted imaging method is proposed in this paper. First, a time-of-flight based weighted function is designed, which can be calculated according to the time-of-flight of potential scatterers and scattering signals. Then, the Hausdorff distance between the reference signal and the damage signal is implemented as damage influencing factor to characterize the impact of the damage on the sensing path. Finally, all time-of-flight based weighted functions are multiplied with damage influencing factors and fused for damage imaging and localization. The experimental results show that this method has less artifacts and lower positioning error, and can accurately locate crack damage with different states compared with other imaging methods.