The need for noncontact, nondestructive evaluation make laser-based ultrasound a promising method for quality control of complex manufacturing processes such as additive manufacturing (AM). Industrial applications of additive manufacturing components are increasing rapidly. Consequently, quality control of the parts become important for safe use of these materials. In order to identify the defects and determine material properties of AM by laser-based ultrasound, the generated ultrasonic signal must be well understood and take into consideration thermal transients caused by rapid heating and cooling of the printed parts. Numerical modelling can allow the interplay of the various factors to be studied leading to improved experimental design. This paper presents analytical and finite element modelling (FEM) simulation results of laser generated ultrasonic waves in SS17 4 PH additive manufacturing materials during the cooling process following laser sintering. The propagation of the laser generated ultrasound waves is modelled including the thermal history of sintering process. The FEM models for the AM parts were generated by importing X-ray CT scans of additive samples into COMSOL (COMSOL Inc.) to include as-built porosity data. This work was sponsored by ASNT research fellowship award.
 Taheri, H., M. R. Mohammad Shoaib, L. W. Koester, T. A. Bigelow, P. C. Collins, and L. J. Bond, “Powder based additive manufacturing - A review of types of defects, generation mechanisms, detection, property evaluation and metrology,” Int. J. Addit. Subtractive Mater. Manuf., vol. 1, no. 2, p. In Press, 2017.
 Koester, L., H. Taheri, L. J. Bond, D. Barnard, and J. Gray, “Additive manufacturing metrology: State of the art and needs assessment,” in AIP Conf. Proc. 1706, 2016, p. 130001.
 Bigelow, T. A., H. Taheri, L. W. Koester, P. C. Collins, and L. J. Bond, “‘Laser-Ultrasound and Acoustic In-Line Monitoring of 3D Metal Printing’ Presented at the "NSF-Sponsored Workshop: Accelerating NSF Research in Additive Manufacturing toward Industrial Applications", Pittsburgh, PA, August 17-18, 2017.
 Scruby, C. B., R. J. Dewhurst, D. A. Hutchins, and S. B. Palmer, Research Techniques in Nondestructive Testing, Vol. V. New York,: Academic Press, Inc., 1982.
 Rose, L. R. F., “Point-source representation for laser-generated ultrasound,” J. Acoust. Soc. Am., vol. 75, no. 3, pp. 723–732, 1984.
 Miller, G. F. and H. Pursey, “The field and radiation impedance of mechanical radiators on the free surface of a semi-infinite isotropic solid,” Proc. R. Soc. London A Math. Phys. Eng. Sci., vol. 223, no. 1155, pp. 521–541, 1954.
 Hutchins, D. A., R. J. Dewhurst, and S. B. Palmer, “Directivity patterns of lase-generated ultrasound in aluminum,” J. Acoust. Soc. Am., vol. 70, no. 5, pp. 1362–1369, 1981.
 Taheri, H., T. A. Bigelow, and L. J. Bond, “Wavefield modeling, and propagation of ultrasound for additive manufacturing materials,” Ames, IA- Technical report, 2016 ASNT fellowship award, 25 pages, 2017.
 Taheri, H., L. W. Koester, T. A. Bigelow, and L. J. Bond, “Finite Element Simulation and Experimental Verification of Ultrasonic Non-Destructive Inspection of Defects in Additive Manufacturing Materials,” in AIP Conf. Proc., Review of Progress in Quantitative Nondestructive Evaluation, Provo, UT, July 2017.
 COMSOL, “COMSOL Inc., Burlington, MA.” COMSOL Inc., Burlington, MA, 2017.
 Schneider, B., H. Taheri, and T. A. Bigelow, “Processing Raw CT Image Data for 2D and 3D Export into COMSOL Modelling,” Technical Report, Center for Nondestructive Evaluation (CNDE), Iowa State University, Ames, IA, 13 pages, 2017.
 Schneider, B., H. Taheri, and T. A. Bigelow, “Converting CT Scans to 2D and 3D Models for COMSOL Modelling Export Manual,” Technical report, Center for Nondestructive Evaluation (CNDE), Iowa State University, Ames, IA, 13 pages, 2017.
 Stafe, M., C. Negutu, and I. M. Popescu, “Combined experimental and theoretical investigation of multiple-nanosecond laser ablation of metals,” J. Optoelectron. Adv. Mater., vol. 8, no. 3, pp. 1180–1186, 2006.
 Scruby, C. B., and L. E. Drain, Laser Ultrasonics Techniques and Applications. CRC Press, 1990.
 Nowacki, W., Dynamic Problems of Thermoelasticity. Noordhof, Leiden: Noordhof International Publishing, 1975.
 Bond, L. J., J. N. Gray, F. J. Margetan, D. Utrata, and I. E. Anderson, “NDE for adding value to materials from metal powder processing,” in Advances in Powder Metallurgy and Particulate Materials - 2014, Proceedings of the 2014 World Congress on Powder Metallurgy and Particulate Materials, PM 2014& Particulate Materials, pp. 1944–1959, 2014.
 Metal AM, “Metal powders – the raw materials,” 2017. [Online]. Available: http://www.metal-am.com/introduction-to-metal-additive-manufacturing-and-3d-printing/metal-powders-the-raw-materials/.[Accessed: 19-Sep-2017].
 CNDE, “NDT Resource Center” [Online]. Available: https://www.nde-ed.org/. [Accessed: 19-Sep-2017].
 Scruby, C. B., R. J. Dewhurst, D. A. Hutchins, and S. B. Palmer, “Quantitative studies of thermally generated elastic waves in laser-irradiated metals,” J. Appl. Phys., vol. 51, no. 12, pp. 6210–6216, 1980.
 Zhang, P., C. F. Ying, and J. Shen, “Directivity patterns of laser thermoelastically generated ultrasound in metal with consideration of thermal conductivity,” Ultrasonics, vol. 35, no. 3, pp. 233–240, 1997.
 Krylov, V. V., “Directivity patterns of laser-generated sound in solids: Effects of optical and thermal parameters,” Ultrasonics, pp. 0–14, 2015.
531 Page Views
0 PDF Downloads
0 Facebook Shares