Resonant Ultrasound Spectroscopy for Quality Control of Geometrically Complex Additively Manufactured Components
Open Access
- Author:
- Mc Guigan, Samantha
- Graduate Program:
- Engineering Science and Mechanics
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- June 30, 2020
- Committee Members:
- Andrea Paola Arguelles, Thesis Advisor/Co-Advisor
Parisa Shokouhi, Thesis Advisor/Co-Advisor
Jacques Riviere, Committee Member
Judith Todd Copley, Program Head/Chair - Keywords:
- Resonant Ultrasound Spectroscopy
RUS
Additive Manufacturing
Lattice Structures - Abstract:
- Metal additive manufacturing (AM) has started to overshadow traditional manufacturing practices thanks to its ability to produce complex, high-performance and application-customized components. However, AM process parameters have not been optimized, leading to inconsistencies and imperfections such as cracks and pores in parts, as well as deviations from the original design. Nondestructive evaluation (NDE) methods used for part qualification such as x-ray computed tomography (CT) and conventional ultrasonic testing (UT) have limitations in their abilities. X-ray CT is costly, hazardous, and offers limited resolution for larger components while many UT methods have limited applicability for inspection of parts with complex geometries or rough surfaces. Here, we conduct an integrated numerical and experimental study to investigate the feasibility of resonance ultrasound spectroscopy (RUS) as an alternative NDE method to inspect complex AM lattice structures with a varying number of missing struts. The most encouraging results are obtained when test samples have traction-free boundary conditions. The results of numerical simulations including eigenfrequency and frequency domain analyses are promising, indicating that the pristine and defective lattice samples should theoretically be distinguishable. In addition, given a reference intact sample, characterizing the extent of the defect in terms of the number of missing struts appears feasible. We introduce a similarity metric to compare the spectra after being locally normalized. However, the experimental results are not as conclusive. Although pristine and defective lattices may be distinguished for some cases, the number of missing struts cannot be inferred. The discrepancies between the numerical and experimental results are likely due to our simplified assumptions about material properties in numerical simulations and/or the presence of other unaccounted defects and heterogeneities in test samples.