Simulation of ultrasonic scattering from inclusions using laser engravings in glass samples

This paper presents a simple alternative for the analysis and evaluation of ultrasonic scattering from arbitrary formed inclusions in materials. The basis for this are glass samples. Their sound velocity (longitudinal and transversal) can be adjusted by the composition of the glass so that it will be similar to the sound velocity of e. g. titanium alloy Ti6246. The propagation of the sound fields in both materials is then comparable. Using laser engraving arbitrary formed three dimensional structures/voids can be built in glass. The surface of these internal structures consists of many micro cracks. By varying the micro crack concentration the sound transmission and reflection can be adjusted. By this means the ultrasonic scattering of impurity inclusions can be simulated. For verification different laser engraved voids (spheres, cylinders and ellipsoids) were built up in glass samples. They were inspected using focused ultrasonic probes. For comparison a titanium sample (Ti6246) containing carbide and quartz inclusions was produced. Additionally the experimental situations were calculated using numerical simulation. Experimental and simulation results show that the correlation of ultrasonic scattering between laser engravings in glass samples and inclusions in titanium is good. Given that the production of glass samples with laser engravings is inexpensive, fast and reproducible, they offer a practical method to perform POD analysis.