Bonding defect detection of multilayer composites by acoustic resistance method

A new multilayer composite material made of stainless steel, rubber, heating components and glass fiber bonded for helicopter blades requires strict quality control due to its complex structure and harsh working environment. The signal aliasing phenomenon of conventional ultrasonic detection is serious and the defects of rubber and glass fiber bonding layer cannot be detected. In this paper, based on the analysis of the mechanical impedance of the composite material, a model based on the acoustic resistance method was established to detect the composite material, and two parameters were derived to characterize the bonding defect information. Experiments showed that the phase and amplitude of mechanical impedance can be used to characterize the depth and size of material defects. The acoustic resistance method had high reliability and high defect detection rate.