Non-destructive evaluation (NDE) using acoustic vibrations is a widely used method to assess unique structures and composite materials. Non-contact forms of ultrasonic NDE, such as laser-induced ultrasound, are particularly suited for in situ evaluation in extreme environments. Current limitations of this method include the inability to identify shadowed defects, probe double-walled vessels, and evaluate surfaces with unfavorable conditions for laser absorption.
Corvid Technologies proposes an innovative ultrasound technique that generates acoustic waves beneath the surface of the target material body using Pulsed Radiation-Induced Acoustics (PRIA). This method uses pulsed radiation to deposit energy within a target material and create a thermoelastic acoustic response. This can be paired with conventional and well-understood non-contact sensing techniques, such as laser interferometry, for a fully non-contact NDE technique that possesses an additional Cartesian degree of freedom for ultrasonic source generation. The ability to generate ultrasonic waves at a variable depth would allow for ultrasonic NDE in the presence of layered defects, inhibitive material properties, prohibitive geometries, or complex material boundaries.
Corvid proposes a series of simulations to determine the feasibility of using radiation to develop thermoelastic waves, characterize the resulting waves, and demonstrate the ability to detect simulated shadowed defects. Corvid will first use the Monte-Carlo particle tracking software GEANT4 to determine the feasibility of several radiation source types and configurations, and determine the energy deposition of each. The molecular dynamics software LAMMPS will take the output of GEANT4 and simulate the response of the materials of interest. The results from LAMMPS will be input into the finite-element code Velodyne to determine the macroscopic wave properties from the pulsed radiation and simulate the waves in the presence of defects.
Corvid foresees PRIA being utilized by NASA for the inspection of complex or non-traditional geometries, or for the advanced inspection of material with multiple layers of defects that may not easily be detected with currently available methods. Existing structures in space can likewise be inspected using PRIA where thermal imaging or laser induced ultrasound may be inhibited by surface condition/coatings. With miniaturization and optimization for known structures, PRIA can be a low cost and viable alternative to existing methods used by NASA.
The use of double walled/insulated vessels across all branches of the military and in many industrial settings makes PRIA a valuable potential resource for inspection. Specific companies who could also utilize PRIA include aerospace manufacturers such as Boeing, and utilities that operate nuclear plants such as Duke Energy, who could use PRIA to evaluate reactor equipment and structures.