SIMULATION TOOLS FOR ULTRASONIC INSPECTIONS OF MULTI-LAYER ARMOR PANELS

Some armor panels are fabricated from several layers of material including ceramics, graphite and/or glass composites, and rubber. This multi‐layer makeup can complicate UT inspection, since many possible sound paths (including intra‐layer reverberations) can contribute to observed UT signals. At last year’s QNDE conference we reported on baseline property measurements (density, sound speed, attenuation, etc.) for the constituent layers of one prototype panel, and we discussed how that information was used to design an ultrasonic inspection to look for disbonding at interfaces. We now report on progress to develop better simulation tools for armor panel inspections. In particular we consider normal‐incidence pulse/echo inspections and use a paraxial beam model to predict time‐domain signals for unflawed panels and those containing large delaminations. The model uses the frequency‐dependent baseline property data as inputs, and treats beam spread and focusing effects. We describe the modeling approach and ...