Current widespread R&D trend in aeronautics is the use of electromechanical actuators for primary and secondary flight controls and for landing gear applications, often stepping up from an already existing hydraulic or electrohydraulic actuation (EHA) solution to an electromechanical one (EMA). While EMAs must always guarantee the compliance to similar performance requirements and equal safety requirements, they sometimes must also respect the envelope and integration constrains given by the direct substitution of an already existing hydraulic solution. In the context of the current "More Electric Aircraft" trend and within a project of the European Aeronautical R&D framework Clean Sky 2, named ASTIB, an innovative EMA architecture has been preliminarily designed for a regional aircraft landing gear application featuring embedded functions of extension/retraction, uplock and downlock. In such a scenario, the present paper is focused on describing the design loops that led to the definition and optimization of the EMA architecture, with a focus on the end-stroke impact issue which may occur in case of disconnection of the EMA for emergency extension and consequent free-fall at high speed of the landing gear. The estimated impact forces were investigated with three different approaches (analytical-numerical-FEM explicit) aimed to obtain as more accurate and reliable results as possible. The attained outcomes show how the three analyses methods converge to similar results even if with much different computational efforts. In an industrial context, such a difference may have a not negligible impact into design cost and schedule.
Electromechanical actuation for landing gear application: A case study on end-stroke impact in case of high speed free-fall emergency extension
Massimiliano Palmieri;Pispola Giulio;Claudio Braccesi;Filippo Cianetti
2018
Abstract
Current widespread R&D trend in aeronautics is the use of electromechanical actuators for primary and secondary flight controls and for landing gear applications, often stepping up from an already existing hydraulic or electrohydraulic actuation (EHA) solution to an electromechanical one (EMA). While EMAs must always guarantee the compliance to similar performance requirements and equal safety requirements, they sometimes must also respect the envelope and integration constrains given by the direct substitution of an already existing hydraulic solution. In the context of the current "More Electric Aircraft" trend and within a project of the European Aeronautical R&D framework Clean Sky 2, named ASTIB, an innovative EMA architecture has been preliminarily designed for a regional aircraft landing gear application featuring embedded functions of extension/retraction, uplock and downlock. In such a scenario, the present paper is focused on describing the design loops that led to the definition and optimization of the EMA architecture, with a focus on the end-stroke impact issue which may occur in case of disconnection of the EMA for emergency extension and consequent free-fall at high speed of the landing gear. The estimated impact forces were investigated with three different approaches (analytical-numerical-FEM explicit) aimed to obtain as more accurate and reliable results as possible. The attained outcomes show how the three analyses methods converge to similar results even if with much different computational efforts. In an industrial context, such a difference may have a not negligible impact into design cost and schedule.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
