Advanced model development and validation of landing gear shock struts

Abstract

Despite the generalization of multi-physical software dedicated to aircraft virtual prototyping, the need for accurate models of landing gear shock struts is still not met. Based on this consideration, the present work aims at providing a lumped parameter model of free surface oleopneumatic shock struts, allowing an accurate prediction of the chamber pressures during landing and involving a limited number of parameters. This will significantly reduce the cost and development time for running real drop tests. The model explicitly treats the heat exchange between gas and oil. It also takes into account physical phenomena, usually left aside, such as chamber compliance, gas dissolution, and gas/oil mixed flow between chambers. Finally, the virtual shock strut prototype is validated through comparison of simulated and measured pressures over two different (in size) shock struts, showing very accurate results and prediction capacity.