Ultrasonic waves can find bubbles and cracks in adhesive
bonds holding airplane composite parts together, and now aerospace engineers
can select the best frequencies to detect adhesive failures in hard-to-reach
places more quickly, thanks to Penn State researchers.
Different ultrasonic modes work best for different materials
and configurations using the right one will locate more flaws with higher
precision, according to the researchers. The selection process could save time
and effort for engineers who perform maintenance on complex structures made
from composite materials -- like airplanes.