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The application of a production-oriented high-power CO2 laser system for the welding of auto underbody components is reported. Sheet metal sections, varying in thickness from 0.060-0.135 in, are welded at speeds up to 500 in/min at 6 kW. An overview of recent developments in laser welding is presented along with a discussion of the laser deep-penetration weld phenomenon. A comparison is made between laser and electron-beam welding performance.

It is desired to reduce stator end winding length and mass to reduce associated resistive losses, increase efficiency and power density of an induction motor. With recent advancements in additive manufacturing technology, it is possible to deposit copper conductive paths and insulation layers in a selective controlled manner. This enables more compact end winding designs. The objective of this paper is to present a topology optimization based approach for design of stator end winding to minimize its overall length, volume and mass. Design approach and parametric study results for a representative stator design are presented in this paper. By reducing length of end winding, efficiency and power density of the induction motor can be increased enabling benefit realization for weight critical aerospace applications, incorporation in electric vehicle market and potentially reducing rare-earth dependency.

Over the past decade, fuel cell systems have begun to appear as both primary and auxiliary power sources for aircraft. Fuel cells enable quiet electric aircraft with endurances that exceed equivalent battery powered vehicles, but have been limited to efficient fixed-wing aircraft due to low fuel cell power-to-weight ratios. This paper begins by discussing polymer electrolyte membrane fuel cell (PEFC) advancements at United Technologies Corporation (UTC) that have resulted in a significant increase in both the power-to-weight and power-to-volume ratios of fuel cell systems. As a result of these advances, UTC PEFC systems can now enable longer endurance missions for smaller UAVs as well as be considered for electric aircraft requiring vertical takeoff and landing capability. The move into vertical takeoff for electric aircraft is of particular interest as capabilities such as hover, perch and stare, and runway independence are enabled.

A novel approach to vehicle airborne contaminant removal based on UV illumination of the photoactive semiconductor TiO2 (titania) at room temperature is described. This paper describes fundamental surface chemistry measurements, prototype development, and theoretical models needed for practical application of the technology. The process of incorporating this information into the design of effective air-purifiers for cabin air applications is described.

This paper presents a demonstrator developed in the European CleanSky2 project MISSION (Modelling and Simulation Tools for Systems Integration on Aircraft). Its scope is the development towards a seamless integrated, interconnected toolchain enabling more efficient processes with less rework time in todays, highly collaborative aerospace domain design applications. The demonstration described here, consists of an open, modular and multitool platform implementation, using specific techniques to achieve fully traceable (early stage) requirements verification by virtual testing. The most promising approach is a model based integration along the whole process from requirements definition to the verified, integrated (and certified) system. Extending previous publications in this series, the paper introduces the motivation and briefly describes the technical background and a potential implementation of a workflow suitable for that target.

The advancement of both sensory and unmanned technology, combined with increased utilization of autonomous platforms in complex teaming scenarios, has created a need for practical design space exploration tools to aid in the synthesis of effective System-of-Systems (SoS). The presented work describes a modular, flexible, and extensible framework, referred to herein as the Technologies and Teaming Evaluation (TATE) framework, for straightforward identification of high-quality SoS, which may include both manned and autonomous elements, through quantitative evaluation of system-level and SoS-level attributes against a set of user-defined reference tasks.

Sulfidation attack, the accelerated oxidation of gas turbine components, occur when the surfaces are covered with a fused alkali salt. Oxide ions present in the melt, react with and render the normally protective oxide scale ineffectual allowing the salt to oxidize the substrate. Turbogard™, a chromium containing fuel additive, attenuates sulfidation corrosion. Turbogard reacts with and alters the oxide ion content of the corrosive melt. Even in the presence of corrosive lead deposits, hot corrosion attenuation was observed.

Induction machines (IM) are considered work horse for industrial applications due to their rugged, reliable and inexpensive nature; however, their low power density restricts their use in volume and weight limited environments such as an aerospace, traction and propulsion applications. Given recent advancements in additive manufacturing technologies, this paper presents opportunity to improve power density of induction machines by taking advantage of higher slot fill factor (SFF) (defined as ratio of bare copper area to slot area) is explored. Increase in SFF is achieved by deposition of copper in much more compact way than conventional manufacturing methods of winding in electrical machines. Thus a design tradeoff study for an induction motor with improved SFF is essential to identify and highlight the potentials of IM for high power density applications and is elaborated in this paper.

Induction machines (IM) are considered work horse for industrial applications due to their rugged, reliable and inexpensive nature; however, their low power density restricts their use in volume and weight limited environments such as an aerospace, traction and propulsion applications. Given recent advancements in additive manufacturing technologies, this paper presents opportunity to improve power density of induction machines by taking advantage of higher slot fill factor (SFF) (defined as ratio of bare copper area to slot area) is explored. Increase in SFF is achieved by deposition of copper in much more compact way than conventional manufacturing methods of winding in electrical machines. Thus a design tradeoff study for an induction motor with improved SFF is essential to identify and highlight the potentials of IM for high power density applications and is elaborated in this paper.

Formal Methods, and in particular Model Checking, are seeing an increasing use in the Aerospace domain. In recent years, Formal Methods are now commonly used to verify systems and software and its correctness as a way to augment traditional methods relying on simulation and testing. Recent updates to the relevant Aerospace regulations (e.g. DO178C, DO331 and DO333) now have explicit provisions for utilization of models and formal methods. At the system level, Model Checking has seen more limited uses due to the complexity and abstractions needed. In this paper we propose several methods to increase the capability of applying Model Checking to complex Aerospace Systems. An aircraft electrical power system is used to highlight the methodology. Automated model-based methods such as Cone of Influence and Timer Abstractions are described. Results of those simplifications, in combination with traditional Assume-Guarantee approaches will be shown for the Electric Power System application.