Harmonic Footprinting

Harmonic Footprints detect "Metal Fatigue"

All metals have a specific Harmonic Frequency, known as a "Vibrational Signature".

Take the case of a bridge.  Bridges move.  They make adjustments to wind, heavy loads caused by traffic, even pedestrians' movement.  Each time a bridge faces a heavy truckload, the stable shape of the bridge changes slightly to handle the stress, producing a Vibrational Signature at each bridge joint. 

Harmonic Footprinting is the process of recording the Vibrational Signature of each bridge joint over a period of time. This is accomplished by installing tiny sensors into the metal joints.  The "Footprints" are continuously synthesized and stored in a database.  

 

Once the "Footprints" are catalogued, the Bridge is now monitored 24/7, with new Footprints at each bridge joint constantly being captured and sent.  When the new Footprint fails to match the Footprint in the database, the bridge inspector is immediately alerted.  The alert directs the inspector to the exact location of the joint in question.

The versatility of Harmonic Footprinting allows numerous bridges to be monitored simultaneously from a single location.

The Science behind Harmonic Footprinting...

Metals have a molecular structure that when excited demonstrates (presents) a dominant resonant  frequency, a number of minor resonant frequencies, and an amplitude.

These frequencies and amplitudes are dependent and created on and by a number of factors such as the forming process, heat  treatment and quench, machining, elemental exposure and other outside factors.

When an outside stimulus, such as a collision (a weather factor, traffic, heavy load, etc.) is applied to metal, the internal (molecular) structure resonants (vibrates) for some period of time (amplitude).  The degree of time of this amplitude is directly dependent on the degree of the stimulus, the power of the impact or collision.  In addition, the degree of amplitude is directly proportional to the mass of the part length dimensional inconsistencies, and quality of origination.

This resonant frequency, harmonic response, will be similar to metals having the same mass and dimension characteristics, assuming these components are produced under the same conditions.

With these consistencies as constants, the Vibrational Fatigue Evaluation Process (Harmonic Footprints), patented, can be used to determine structural degradation and molecular degradation to any metal having resonant frequencies and amplitudes, thereby determining the remaining service life of the metal component without destructive laboratory testing, or removing the part in question from service.

The methods utilized to determine the resonant frequency and harmonic response in component metals that have been used can also be used to determine factors in new (virgin) parts that will affect the performance or usable life of the part, or cause the part to improperly interact with mating components.  These factors are compressive stresses, inclusions, fractures, voids, and other factors caused by poor forming, heat treat or sintering.

In parts that have been in use, performance and fatigue life can be determined by the same method used to determine the quality of the virgin component.

The method utilized to determine the resonate frequency/amplitude of components in the Vibrational Fatigue Evaluation (VFE) process is based upon base line resonant frequencies and amplitudes determined at the time prior to installation or at the time of installation with software developed by Harmonic Footprinting, LLC.