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Circuit protection fuses are an integral part in electric powertrain based automobiles such as Hybrid electric vehicles (HEVs)/Plug-in hybrid vehicles (PHEVs)/Battery electric vehicle (BEVs) to protect the components under overcurrent situations. This paper describes the transient thermal characteristics of fuses used in such electric vehicles where thermal cycling related failures are of great concern. A robust and accurate three-dimensional multiphysics model has been developed for obtaining temperature response in fuse element by solving the electric potential equation and thermal diffusion equation. Experiments were also performed to validate the model within 5 degree Celsius accuracy for various operating currents and thermocouple locations. Using the validated model, a representative duty cycle relevant to electric vehicle was simulated to understand the thermal behavior. Various operating parameters and their effect on thermal performance is also discussed.

Polytetrafluoroethylene (PTFE) is used extensively as the inner tube material in various Aerospace and Industrial hose constructs. The fluoropolymer exhibits various unique mechanical properties from other fluoropolymers including chemical inertness, non-adhesiveness and low friction coefficient making it an attractive solution for hose applications. PTFE material can be modeled using various material modeling approaches including linear-elastic, hyperelastic and viscoplastic depending on the level of accuracy required in predicting material response. Fluoropolymers, like PTFE, are considered viscoelastic-viscoplastic materials. In other words, the material exhibits both viscous and elastic characteristics when undergoing deformation but also possesses behavior in which the deformation of the material also depends on the rate by which loads are applied.