Aerospace

Abstract: Humankind's aerospace aspirations are placing unprecedented demands on vehicle propulsion systems. Advanced structural ceramics are playing a key role in addressing these challenges.

Abstract: Driven by the increasing requirements from aircraft producers, Hoogovens Aluminium Rolled Products GmbH, together with Hoogovens Research & Development, has enhanced the property combinations of their aircraft materials. For these types of material, optimised processing routes as well as new alloy chemistries have been investigated. Whilst retaining the strength levels required by the aerospace industry, new processing routes offer major improvements in ductility, toughness, fatigue performance and in reduction of residual stress in large dimension plate and sheet products. A further goal of investigating new alloy chemistries is the trend towards new joining techniques such as welding and brazing for aircraft structures. These new joining techniques require different property combinations compared to the conventional aerospace alloys. In parallel to these improved processing routes and new alloy developments, new ultrasonic inspection techniques have been developed, which are able to predict fatigue performance and residual stress in thick plate products.

Abstract: This paper presents an overview of motor drive technologies used for safety-critical aerospace applications, with a particular focus placed on the choice of candidate machines and their drive topologies. Aircraft applications demand high reliability, high availability, and high power density while aiming to reduce weight, complexity, fuel consumption, operational costs, and environmental impact. New electric driven systems can meet these requirements and also provide significant technical and economic improvements over conventional mechanical, hydraulic, or pneumatic systems. Fault-tolerant motor drives can be achieved by partitioning and redundancy through the use of multichannel three-phase systems or multiple single-phase modules. Analytical methods are adopted to compare caged induction, reluctance, and PM motor technologies and their relative merits. The analysis suggests that the dual (or triple) three-phase PMAC motor drive may be a favored choice for general aerospace applications, striking a balance between necessary redundancy and undue complexity, while maintaining a balanced operation following a failure. The modular single-phase approach offers a good compromise between size and complexity but suffers from high total harmonic distortion of the supply and high torque ripple when faulted. For each specific aircraft application, a parametrical optimization of the suitable motor configuration is needed through a coupled electromagnetic and thermal analysis, and should be verified by finite-element analysis.