Theses and Dissertations from UMD

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New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a give thesis/dissertation in DRUM

More information is available at Theses and Dissertations at University of Maryland Libraries.

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Author: search.filters.author.Chaloupka, Andrew CharlesSubject: search.filters.subject.reliability

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    LEAD-FREE ELECTRONICS USE AND REPAIR DYNAMIC SIMULATION
    (2009) Chaloupka, Andrew Charles; Sandborn, Peter A; Mechanical Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    The conversion from tin-lead to lead-free electronics has increased concern amongst engineers about the reliability of electronic assemblies. In order to communicate the impact of the conversion in terms of cost and availability, a simulation of electronic systems at the LRU level to and through a repair facility was created. The model includes the effects of repair prioritization, multiple possible failure mechanisms, no-fault-founds, and un-repairable units. Example analyses were performed on electronic assemblies that use SAC and SnPb solder using a repair process modeled after a NSWC Crane Aviation Repair Process. The case studies revealed that LRUs exposed to usage profiles characteristic of aerospace and high performance applications, high thermal cycling temperatures with short dwell times, SAC exhibited significantly increased repair costs when compared to tin-lead. Prioritizing LRUs and increasing the rate of deployment had no significant impact on the cost or availability metrics for the cases considered.