Publication Date
5-2025
Date of Final Oral Examination (Defense)
3-5-2025
Type of Culminating Activity
Dissertation
Degree Title
Doctor of Philosophy in Materials Science and Engineering
Department
Materials Science and Engineering
Supervisory Committee Chair
Brian J. Jaques, Ph.D.
Supervisory Committee Member
David Estrada, Ph.D.
Supervisory Committee Member
Michael D. McMurtrey, Ph.D.
Supervisory Committee Member
Amey Khanolkar, Ph.D.
Abstract
The advancement and continued use of nuclear energy systems benefit from an increase in fundamental understanding and advancements of the fuels, cladding types, and structural materials employed in nuclear reactors. Experimentation at irradiation test facilities help resolve challenges related to the understanding of these materials; however, due to the harsh conditions generated in such reactors, evaluation of a material’s mechanical properties is often limited to post-irradiation examinations. It is through the development of real-time monitoring techniques of salient materials properties that can help enable this potential towards shortening the time to innovate in nuclear energy technologies. To expand the structural health monitoring capabilities at irradiation test facilities, additively manufactured (AM) strain gauges are demonstrated as a viable alternative to commercially available strain sensors where there are limitations in the allotted experimental space, materials restrictions, and/or appropriate attachment strategies (i.e., adhesive, welding) that can be used. This dissertation aims to provide an understanding of the influence of sensor design, processing, and environmental conditions on the performance and reliability of AM capacitive strain gauges (CSG) to address this need.
While AM techniques have demonstrated the ability to produce functional electronic devices in recent years, there is a limited understanding of the operational impact, environmental resiliency, and robustness of the printed devices in the limiting and harsh environment of reactor experiments. In this dissertation, Chapter 1 discusses the current needs for structural health monitoring in the harsh environment of nuclear reactors. Chapter 2 discusses the initial investigation of AM CSGs with polyimide insulation and encapsulation and their performance on metallic substrates at elevated temperatures. The objectives in this chapter were to fabricate, characterize, and test the performance of the AM CSGs while exposed to separate effects (i.e., mechanical strain, high temperature) and demonstrate their efficacy for harsh environment applications. Chapter 3 discusses the development and implementation of adhesion test methods to investigate the reliability of the interface between printed materials and substrate surface. The work discussed in this chapter develop sensor qualification methodologies that will help establish quality control metrics that measure the robustness and reliability of the AM devices prior to deployment in critical experiments. Chapter 4 discusses the investigation and challenges of using alternative inorganic (e.g., ceramic) printed materials as the electrical insulation and protective encapsulation layer of the CSG. Barium strontium titanate (BST) was explored as a viable alternative to polyimide to increase the operating temperature of CSGs. Finally, Chapter 5 discusses the preliminary experiments that examine the influence of neutron irradiation on the signal of AM printed strain gauge. These developmental AM strain gauges have the potential to mitigate the size limitations of current commercial strain gauges for reactor experiments, especially in application areas where physical space is a challenge. The cumulative work discussed in this dissertation helps develop foundational knowledge on the effects of harsh environmental conditions on AM nuclear sensors.
DOI
10.18122/td.2378.boisestate
Recommended Citation
Phero, Timothy Le, "The Development and Testing of Additive Manufactured Strain Gauges for Harsh Environment Structural Health Monitoring" (2025). Boise State University Theses and Dissertations. 2378.
10.18122/td.2378.boisestate