System for structural health monitoring and/or non-invasive tank fluid level measurement including cryogenic and zero G environments

A system comprising:

• at least three piezoelectric transducers adapted to be in contact with a surface of a structure, said at least three piezoelectric transducers each further comprising Interdigitated Electrodes, said at least three piezoelectric transducers being non-intrusive to the surface and identical in construction, said at least three piezoelectric transducers each being configurable as an actuator and configurable as a sensor;
• a digitizing unit at least configured for communicating a plurality of frequency signals to a first of said at least three piezoelectric transducers, the plurality of frequency signals comprising random white noise extending from approximately 1 Hertz up to an ultrasonic range, said digitizing unit being at least further configured for receiving signals originating from a second and a third of said at least three piezoelectric transducers as said first transducer receives the plurality of frequency signals, wherein said first and said second of said at least three piezoelectric transducers are separated by a first distance, wherein said first and said third of said at least three piezoelectric transducers are separated by a second distance, and wherein said second distance is greater than said first distance;
• an amplifying unit being at least configured for amplifying the plurality of frequency signals from said digitizing unit;
• a relay unit being at least configured for directing signals between said digitizing unit and said at least three piezoelectric transducers;
• a computing unit being at least configured for
• communicating the plurality of frequency signals to said digitizing unit,
• receiving the signals from said digitizing unit originating from said second and said third of said at least three piezoelectric transducers as said first of said at least three piezoelectric transducers receives the plurality of frequency signals,
• generating a fast Fourier transform (FFT) for each of the signals received from said digitizing unit that originate from said second and said third of said at least three piezoelectric transducers, and
• dividing the FFT generated from the signals originating from said third of said at least three piezoelectric transducers by the FFT generated from the signals originating from said second of said at least three piezoelectric transducers to thereby generate a Frequency Response Function, wherein changes to the Frequency Response Function indicate a change to physical properties of the structure, the physical properties of the structure comprising an underlying stiffness and modal mass of the structure;
• and
• a wireless communication link being at least configured for remote access to said computing unit.