Detection of Water Inclusions in Honeycomb Composite Products by a Holographic Radar

Abstract

Detection of water inclusions in honeycomb composites is an urgent task during construction and operation of various aircrafts. This includes diagnostics of helicopter composite rotor blades, since the presence of moisture condensed in the internal air cavities leads to gradual development of cracks and results in blade deterioration, icing and imbalance. The imbalance of helicopter rotor blades may influence the comfort and safety of a flight, result in thrust loss and increased load in dynamic components caused by the helicopter vibration. Currently, restoring balance is a complex and time-consuming procedure under the operating conditions of a helicopter. This paper presents the results of detecting moisture inside the honeycomb structure of the blades using microwave holography, which can be used to simplify and speed up the procedure for their diagnosis and prevent imbalance.