The Nondestructive Inspection of Agglomeration in Nanocomposite Parts Using Shearography and Improving the Results with Design of Experiment

With the recent development and progress in the field of nanocomposite products, their mass production is limited because of the lack of appropriate nondestructive methods to ensure their integrity. Agglomeration of nanoparticles refers to a harmful defect over the nanocomposite materials, affecting the final performance of the material. The present study focuses on identifying the site of carbon nanotube (CNT) agglomeration in nanocomposite samples by nondestructive shearography test. In this regard, several samples of epoxy sheets reinforced by multi-walled carbon nanotubes (MWCNTs) with different levels of agglomeration were prepared. To improve the quality of inspection results Design of Experiments (DOE) technique was used based on Taguchi’s method. Signal-to-noise analysis was utilized to evaluate the tests’ outputs. The optimization of the shearography parameters was conducted based on signal-to-noise ratio (SNR) graphs obtained from the aforementioned analysis. Data analysis indicated that the agglomeration factor has the greatest effect on the results, shear distance and loading size are placed in the next ranks respectively. According to the results, shearography has the potential to be used to verify the health of nanocomposites in mass production.