Ultrasonic inspection system and method

An ultrasonic inspection system for microstructural evaluation of an object, said system comprising:

• an ultrasonic transducer configured to insonify at least one subvolume of the object with ultrasonic energy;
• an ultrasonic receiver configured to acquire receive energy from the object at the fundamental frequency and at least one harmonic frequency thereof;
• and
• a processor configured to determine a nonlinearity parameter using the receive energy, wherein the processor is further configured to use the nonlinearity parameter to determine at least one of (a) a grain size for the subvolume of the object and (b) a variation of the grain size within the object.

A method for degradation evaluation of an object, said method comprising:

• insonifying at least one subvolume of the object with ultrasonic energy, wherein the object is inhomogeneous;
• acquiring receive energy from the object at the fundamental frequency and at least one harmonic frequency thereof;
• determining a nonlinearity parameter using the receive energy;
• and
• using the nonlinearity parameter to determine a plurality of gradients in a residual stress.

A method for nondestructive evaluation of an object, said method comprising:

• insonifying at least one subvolume of the object with ultrasonic energy;
• acquiring receive energy from the object at a fundamental frequency and at least one harmonic frequency thereof;
• determining a nonlinearity parameter using the receive energy;
• and
• using the nonlinearity parameter to determine at least one of an elastic state and a plastic state of the material.