Mississippi State University
Matthew W. Priddy
Date of Degree
Original embargo terms
Complete embargo for 2 years
Graduate Thesis - Open Access
Doctor of Philosophy
James Worth Bagley College of Engineering
Department of Mechanical Engineering
The overall goal of this work is to predict the mechanical response of an as-built Ti-6Al-4V directed energy deposition component by a dislocation mechanics-based internal state variable model based on the component's geometry and processing parameters. Previous research has been performed to connect additive manufacturing (AM) process parameters including laser power and scanning strategy to different aspects of part quality, such as porosity, mechanical properties, fatigue life, microstructure, residual stresses, and distortion. The lack of predictive capabilities to fully estimate residual stresses and distortion within parts produced via AM have hindered part qualification; however, modeling the AM process can aide in process and geometry optimization compared to traditional trial-and-error methods. The presence of unwanted thermally induced residual stresses and distortion can lead to tolerancing issues, reduced fatigue life, and decreased mechanical performance compared to similar components fabricated with traditional manufacturing methods such as casting and machining. A three-dimensional thermomechanical finite element model calibrated using dual-wave pyrometer thermal image datasets along with temperature- and strain rate-dependent mechanical data is utilized for this work. The purpose of this work is to understand the relationship between a component's temperature history and its resultant distortion and residual stresses.
Army Research Laboratory
Dantin, Matthew Joseph, "Thermomechanical modeling predictions of the directed energy deposition process using a dislocation mechanics based internal state variable model" (2021). Theses and Dissertations. 5244.
Available for download on Tuesday, August 15, 2023