Date of Submission

12-2020

Document Type

Thesis

Degree Name

Master of Science in Mechanical Engineering

Department

Mechanical and Industrial Engineering

Advisor

Dr. Eric A. Dieckman

Committee Member

Dr. Maria-Isabel Carnasciali

Committee Member

Dr. Ravi Gorthala

Keywords

Ultrasonic immersion testing system, Ultrasound calibration block, Metals, Selective laser melting

LCSH

Nondestructive testing, Additive manufacturing, Ultrasonic testing, Elastic wave propagation

Abstract

Additive manufacturing is a category of emerging manufacturing processes that have applications in creating metal components with high value and complexity. The adoption of these parts is limited by the lack of fully developed nondestructive techniques for identifying internal defects. The use of ultrasonic testing for detecting and measuring internal features in additively manufactured metal parts is investigated. A low-cost ultrasonic immersion testing system was designed, constructed, and validated for the inspection of an additively manufactured titanium specimen with artificial defects as well as other metal artifacts. An ultrasound calibration block was additively manufactured from stainless steel type 316L and directly compared to a conventionally produced AISI 1018 steel block using standard inspection techniques. It was found that additively manufactured stainless steel has noticeable acoustic anisotropy with its speeds of sound varying nominally by 8% and greater attenuation than 1018 steel by a factor of at least 0.2 Np/in. To accompany experimental results, elastic wave simulations in a commercially available finite element package were explored.

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