“How on Earth did they make that?” asks Francesco Simonetti, commenting on an ice sculpture of a swan.
Simonetti isn’t admiring the artistry of shaping a block of ice into a bird. He’s admiring the swan’s crystal-clear transparency.
Simonetti, an aerospace engineering professor at the University of Cincinnati, is an expert in sound waves, but lately he’s been an apprentice in ice. And when it comes to sound waves, the clearer the ice, the better.
Simonetti recently published a novel approach that uses ultrasound to inspect additive-manufactured parts: He dips the part in water and freezes it inside a cylinder of ice. The ice acts as a coupling medium, letting ultrasonic waves enter and reflect against the part’s potential defects.