Antech Systems proposes to demonstrate a) passive Structural Health Monitoring (SHM) systems can quantitatively identify, locate, and characterize defects, such as cracks and delaminations, using 3D image correlation, and b) how this innovative approach provides a path to commercialization through a more efficient FEA calculational approach to automate the analysis. The development will incorporate and commercialize the use of NASA-developed numerical methods software to characterize the source and guide the image analysis. The approach adds another dimension to the numerically derived dispersion curve plots by adding the amplitude of each frequency component of each mode into the plots using the modeling. This gives a 3D time/frequency/amplitude dispersion curve plot to perform the analysis with – a first. These theoretical curves, which now fully describe a source (e.g., depth, orientation), are correlated against the wavelet transform image of the waveform excited by the defect to accurately identify the source – aka, facial recognition for waveforms. This approach takes guided wave signal analysis out of the 2D/phase velocity space, moves it into a 3D group velocity image analysis (the natural analysis space for guided waves), and directly ties theory to the wavelet image of the raw signal.
The numerically guided image analysis enables automated inspections of large or complex aerospace structures, provides reliable rapid assessments of the location and extent of damage or defects, and registers NDE results to precise locations on the structure. Structural components, such as heat shields, can be practically monitored. Micrometeoroid impact damage has been extensively researched by NASA, and it is well known that the guided wave modes excited are controlled by penetration depth. The 3D image correlation approach extracts that detailed information automatically for any number of modes to accurately characterize impact damage with no manual inspection required.