Doctoral Dissertations

Keywords and Phrases

Additive manufacturing; Laser aided machining and polishing; Metal 3D printing; Metal fatigue characterization

Abstract

“Additive manufacturing (AM) and laser-aided machining and polishing (LAMP) of materials are emerging manufacturing processes both for research and industrial sectors. The AM process can manufacture near-net-shape parts with complex geometries. Meanwhile, the LAMP process integrated with an AM system offers a high processing rate, minimum heat-affected zone, and easily adjustable process parameters during machining and polishing. In mechanical properties characterization of AM metals and alloys, fatigue is a vitally important test method to understand the behavior of materials in cycling loading and unloading circumstances since most mechanical failures of structures are due to fatigue. To characterize AM metal fatigue behavior, it is also crucial to understand and analyze how the fabrication process parameters, build orientations, and defect formations affect the ability of materials to resist fatigue failure. This research aims to study the needed fundamental knowledge for a high-speed fatigue testing method with miniature specimens and investigate the effect of build process parameters on the high cycle fatigue performance of AM materials. In this study, the implementation of miniature specimens with increased surface area and uniform stress distribution within gauges captures a large population of surface and subsurface defects, reduces the stress gradient effect, maintains symmetric loading, minimizes material and test equipment costs, and decreases sample preparation and test time. The acquired knowledge from this study helps understand the influence of defects on the fatigue behavior of AM materials and determine the high fatigue strength yielding process parameters. Since the fatigue strength of materials can be improved by machining and polishing part surfaces, the objectives of this research also include developing a multilaser LAMP process and investigating the effect of different process parameters on part surface quality improvements. The research results lead to new knowledge that could benefit a wide range of manufacturing industries”--Abstract, page iv.

Advisor(s)

Liou, Frank W.

Committee Member(s)

Dharani, Lokeswarappa R.
Chandrashekhara, K.
Midha, A. (Ashok)
Newkirk, Joseph William

Department(s)

Mechanical and Aerospace Engineering

Degree Name

Ph. D. in Mechanical Engineering

Comments

This research was supported by National Science Foundation Grant CMMI-1625736. The author would like to thank NSF, Department of Energy’s Kansas City National Security Campus (KCNSC) operated by Honeywell Federal Manufacturing Technologies, Intelligent Systems Center (ISC), Material Research Center (MRC), and Mechanical and Aerospace Engineering Department (MAE) at Missouri University of Science and Technology.

Research Center/Lab(s)

Intelligent Systems Center

Publisher

Missouri University of Science and Technology

Publication Date

Spring 2022

Journal article titles appearing in thesis/dissertation

  • A Displacement Controlled Fatigue Test Method for Additively Manufactured Materials
  • High Cycle Fatigue Performance of LPBF 304L Stainless Steel at Nominal and Optimized Parameters
  • A Novel Laser-Aided Machining and Polishing Process for Additive Manufacturing Materials With Multiple Endmill Emulating Scan Patterns

Pagination

xii, 107 pages

Note about bibliography

Includes bibliographic references.

Rights

© 2022 Mohammad Masud Parvez, All rights reserved.

Document Type

Dissertation - Open Access

File Type

text

Language

English

Thesis Number

T 12128

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Included in

Manufacturing Commons

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