Theses and Dissertations

Date of Award


Document Type


Degree Name

Master of Science (MS)


Mechanical Engineering

First Advisor

Dr. Constantine Tarawneh

Second Advisor

Dr. Robert Jones

Third Advisor

Dr. Arturo Fuentes


Many freight railcars rest on polymer adapter pads made of injection-molded Thermoplastic Polyurethane (TPU) polymers which feature two copper studs to provide electrical conductivity through the adapter pads, which power onboard systems. In service, pads experience impact and cyclic loading, resulting in wear and plastic compression of the copper studs. This leads to signal interruptions and periodic replacement of the polymer pads, which results in downtime due to maintenance and reduced reliability since pad failure is unpredictable. These limitations in the current design are the impetus to create an electrically conductive polymer adapter pad that does not rely on the inclusion of metal components that are susceptible to wear. Therefore, the University Transportation Center for Railway Safety (UTCRS) has been developing a conductive composite blend of TPU and Carbon Nanofibers (CNF) to create injection-molded polymer composite inserts. The work presented in this thesis focused on fiber alignment that would produce consistent conductivity at all railcar loads. Test results were successful and show that the newly created composite inserts with proper fiber orientation provide approximately double the needed conductivity required for a 24-Volt railcar valve to actuate when tested under the minimum load conditions an adapter would experience in field service.


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