Capacitive Array Technology for Composite Rotor Blade NDI

This SBIR will focus on glass and carbon fiber composite NDI for CH-47, UH-60 and AH-64 blades. Phase II will develop a new electric field/capacitive sensing NDI inspection method for glass fiber composites; specifically for surface and buried cracks and manufacturing anomalies. Phase I successfully demonstrated a dual field sensor for buried/subsurface crack detection and sizing, a method that is similar to eddy current testing (ET) of metals. We address two specific gaps: measuring depth of surface breaking cracks; detecting buried/subsurface cracks emanating from manufacturing anomalies. We will advance linear drive eddy current arrays for disbond, delamination, impact damage and manufacturing anomaly imaging in carbon fiber composite blades. Linear drive eddy current sensor arrays, called MWM-Arrays, overcome limitations of circular coils by enabling substantial induced eddy currents to be formed in the carbon fibers. In Phase I we successfully demonstrated impact damage and manufacturing anomaly imaging for uniaxial and biaxial fiber composites. This Phase II will also develop finite element models to demonstrate the effects of NDI indications on residual strength to support condition based maintenance. The goal is to deliver practical NDI tools for rapid field NDI of rotorcraft blades. We are teaming with two rotorcraft OEMs and MR&D.