Detection of bond defects in a helicopter rotor blade by acoustic impact technique

Abstract

The Chetak/Cheetah Helicopter main rotor blade is an all metal blade and is made of Aluminium alloy and stainless steel members bonded together. The hollow portion of the blade is filled with Maltoprene foam. One of the major problems encountered with the blade is debonding between different members. So, a program was undertaken at the institute to detect and contour these defects by Acoustic Impact Testing (AIT). In the program undertaken a section of the rotor blade was fabricated with defects intentionally introduced at different interfaces. Different areas were scanned to detect and contour the existing defects. The results of the experiments show that analysis in frequency domain is more reliable and could easily be standardised.