Engineering Commons^™

Capabilities Of Sintered Silver As A High Temperature Packaging Material, Bakhtiyar Mohammad Nafis

Graduate Theses and Dissertations

With electrification progressing across many sectors including industry, automotive and aerospace, the power density requirements are changing. The increased power density results in higher and higher ambient temperatures that electronics are exposed to. The response has been to move towards wide bandgap (WBG) semiconductor devices that can withstand much greater temperatures and can operate at much higher voltages than silicon. Additionally, these WBG devices deliver low drain-source on resistance (RDS_on) capabilities, enabling high current power modules that increase power density even further. This also requires the packaging to evolve in order to withstand the new requirements. As a result, researchers …

Relating Surface Resistivity To Corrosion Of Rebar Embedded In Portland Cement Concrete, Luisa Alejandra Morales

Open Access Theses & Dissertations

Reinforced concrete is widely used as a construction material known for its durability and proficiency of withstanding large forces in severe environments. Despite that the majority of these structures result in long-term performance, there is still a large number of failures of reinforced concrete structures as a result in corrosion of the reinforcement and concrete degradation. It is critical to assess the state of the corroded structure to decide on whether maintaining or replacing the structure is needed. The objective of this study is to characterize a relationship between the steel reinforcement corrosion and the concrete's resistivity. It is widely …

Flexible Analysis Of Creep Rupture Database And Accelerating The Acquisition Of Creep Rupture Data, Christopher Ramirez

Open Access Theses & Dissertations

A comprehensive statistical analysis of creep data is a difficult task because there are many layers of uncertainty for a given dataset. Sources of uncertainty are inherent in both the databases that provide data, and the data themselves. Additionally, creep rupture predictions made with time-temperature parameter (TTP) models add an additional layer of uncertainty due to the fundamentally different ways in which each TTP model predicts creep behavior. A set of guidelines from the ECCC currently exist for such analyses, but they are best suited for narrowly-defined datasets. In this study, a broader set of guidelines are developed to analyze …

Temperature And Stress Effect Modeling In Fatigue Of H13 Tool Steel At Elevated Temperatures With Applications In Friction Stir Welding, Bradley Valiant Jones

Theses and Dissertations

Tooling reliability is critical to welding success in friction stir welding, but tooling fatigue is not well understood because it occurs in conditions that are often unique to friction stir welding. A fatigue study was conducted on a commonly used tooling material, H13 tool steel, using constant stress loading at temperatures between 300°C and 600°C, and the results are presented. A model is proposed accounting for temperature and stress effects on fatigue life, utilizing a two-region Arrhenius temperature model. A transition in temperature effect on fatigue life is identified. Implications of the temperature effect for friction stir welding suggest that …

An Accelerated Testing System To Determine Percent Crushed Aggregate Requirements In Bituminous Mixtures, Thomas D. White, J. M. Abers, John E. Haddock

JTRP Technical Reports

With increase in axle loads, tire pressures and volume of truck traffic there has been an increase in the rate of which bituminous pavements are exhibiting rutting. Because resistance to rutting can be increased by the addition of crushed aggregate, a need exists for a method of determining what amount of crushed material is required and the characteristics of that crushed material to optimize performance and economy.

The Accelerated Testing Facility will be located at the INDOT Research Division Facilities in West Lafayette, Indiana. A pit within the Test Facility will allow prototype scale pavement sections to be installed. An …