Continuous unidirectional ceramic fiber and woven fabric reinforced metal matrix composites (MMCs) have potential to obtain very high specific strengths and stiffnesses, but use in structural applications has thus far been limited by their inherently low ductility, particularly in tensile loading conditions. In this work, a multi-scale micromechanics based finite element framework is used to predict, and understand the effect of microstructure on the tensile deformation behavior, including progressive damage and failure, of ceramic fiber and fabric reinforced MMCs. A hierarchal approach is implemented in which a micro-scale model is used to determine the transversely isotropic elasto-plastic mechanical behavior of unidirectional fiber reinforced MMC based on the properties of an aluminum alloy matrix, individual ceramic fibers, and the fiber-matrix interface. The validated transversely isotropic constitutive behavior is then input into a unit cell model for a woven fabric MMC consisting of unidirectional MMC tows in

Cordless power drills are currently being designed with lithium-ion battery technology to produce more power per unit mass as compared to legacy nickel-cadmium battery packs. With this increase in power, more complex heat removal solutions are needed to dissipate heat resulting from electrical circuit resistance and insure electronic components, specifically the metal oxide semiconductor field effect transistor (MOSFET), will remain below its maximum operating temperature of 175°C. Heat spreaders, ventilation methods, and heat sinks were considered, with a newly designed heat sink being determined to be the most effective solution that met performance, manufacturing and cost requirements. Finite element models of the heats sinks along with models of the natural convection within the drill were developed and used to determine geometry and material requirements. Laboratory tests were performed on several prototype heat sinks and drills to validate the thermal modeling and ensure designs would meet the required performance metrics. From testing, it was seen that the new design absorbed the required amount of heat, keeping the MOSFET and handle temperature at 88°C. This insures the durability of the tool, keeping the temperature below the plastic deformation temperature of the drill handle. From the modeling and testing of this solution, a new design methodology was created and validated to expedite design iterations for future drill models and other cordless tool products.

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