Thermoelastic Finite Element Modeling of Laser Generated Ultrasound in Additive Manufacturing Materials

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.


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