Monitoring the damage evolution of Al 6061-T6 laser welded T-joint structure using nano-carbon tube based buckypaper film sensor

In this paper, buckypaper (BP) thin film sensor was used to monitor the health of Al 6061-T6 laser welded T -joint structure, including the strain and damage evolution of the joint during tension and bending. Al 6061-T6 T -joint was welded by laser welding technology. Laser welding technology of aluminum alloy is an advanced connection technology, which is of great significance for lightweight and efficient manufacturing of aerospace plate structure. BP sensor was prepared by using commercial multi-walled carbon nanotubes (MWCNTs) through dispersion, vacuum filtration and other processes. It has the advantages of simple manufacture, low cost, wide detection range and good stability. The experimental results indicate that the sensor has advantages such as high sensitivity, high stability, and repeatability. And the sensor can effectively monitor the strain and damage of the joint under tensile load. According to the resistance response of the sensor, three areas can be clearly identified, and joint damage can be predicted in advance. At the same time, sensors can also monitor the deformation of joints under bending, accurately reflecting the status of the joints.