Impedance Inspection System and Method for using Same

An impedance-measuring inspection system comprising:

• a probe assembly including a first electrode and a second electrode;
• and
• a control assembly including a signal generator, a measurement channel, and a processing system, the signal generator electrically connected with the first electrode, the measurement channel electrically connected with the second electrode, the processing system including a processor connected in signal communication with a non-transitory memory storing instructions which, when executed by the processor, cause the processor to:
• measure, using the measurement channel, an impedance of a component between the first electrode and the second electrode while controlling the signal generator to generate an alternating current (AC) output to the first electrode over a frequency range extending between a first AC frequency and a second AC frequency;
• determine an impedance differential of the impedance over the frequency range;
• generate an impedance differential profile for the component with the impedance differential determined for a plurality of different positions on the component;
• and
• identify a presence or an absence of a defect condition of the component using the impedance differential profile.

A method for inspecting a component for an aircraft propulsion system with an impedance-measuring inspection system, the method comprising:

• for each of a plurality of different positions on the component,
• positioning a probe assembly of the impedance-measuring inspection system at one of the plurality of different positions with a first electrode and a second electrode of the probe assembly contacting the component,
• applying a vibrational excitation to the component at a vibratory frequency with a piezoelectric actuator of the probe assembly,
• measuring an impedance of the component between the first electrode and the second electrode over a frequency range extending between a first alternating current (AC) frequency and a second AC frequency while applying the vibrational excitation to the component to determine an impedance curve for the component, and
• determining an impedance differential of the impedance curve over the frequency range;
• and
• identifying a presence or an absence of a defect condition of the component using an impedance differential profile for the component including the impedance differential at each of the plurality of different positions on the component.