Session: 15-01: Structural Health Monitoring

Paper Number: 97949

97949 - Real-Time Evaluation of Additive Manufacturing Parts Using Laser Vibrometer Combined With Shock Tube 

Additive manufacturing (AM) parts are prone to a combination of different defects and, given their certain degree of individuality, require individual quality control. Such quality control is typically conducted via nondestructive evaluation (NDE) techniques, yet after the part is fabricated. The implementation of real-time NDE could highly benefit manufacturing by enabling on-time adjustment of the fabrication process, or simply by discarding the part before its completion, therefore resulting in savings on materials, time, and equipment usage. However, real-time evaluation of AM parts is a challenging task due to the non-contact requirement of the NDE process. The authors proposed a new resonant method to nondestructively evaluate AM parts in real-time that combines 1) a controlled shock wave as the excitation source to create a non-contact and dynamic response for the AM parts through pressurization of air; and 2) a laser vibrometer to remotely measure full-field responses of AM parts while being fabricated. The Pearson correlation coefficient is employed to evaluate the similarity between frequency spectra for the AM parts and is further adopted as a metric for localizing and quantifying defects. Tests were conducted on cylindrical samples with induced defects, including voids, melting temperature variations, and local changes in thicknesses. Results showed that the presence of defects or any changes in the parts’ geometry, internal structure, and mechanical properties created a detectable change in the resonance frequency spectra. Further tests were conducted on a set of electrode weld stacks assembled under different conditions. Results showed that the technique was capable of ranking of specimens depending on their conditions.

Presenting Author: Han Liu Iowa State University