Frequency Response Inspection of Additively Manufactured Parts for Defect Identification

Johnson, Kevin
Blough, Jason
Barnard, Andrew
Hartwig, Troy
Brown, Ben
Soine, David
Collum, Tristan
Kinzel, Edward
Bristow, Douglas
Landers, Robert
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University of Texas at Austin

The goal of this paper is to evaluate internal defects in AM parts using dynamic measurements. The natural frequencies of AM parts can be identified by measuring the response of the part(s) to a dynamic input. Different excitation methods such as a modal impact hammer or shakers can be used to excite the parts. Various methods exist to measure the parts’ responses and find the natural frequencies. This paper will investigate the use of Doppler lasers, accelerometers and Digital Image Correlation (DIC). The parts evaluated in this work include sets of parts that are still attached to the AM build plate, this makes the identification of a faulty part much more difficult as parts on a build plate interact with each other as well as the build plate complicating the responses. Several approaches to these issues will be presented based on the above listed response measurements.