Dynamical model and numerical algorithms and procedures for dynamic simulation of landing and taxi of large transport aircraft are developed in the framework of the project 'Dynamic simulator for transport aircraft landing analysis'. The mathematical model and computational procedures are based on non-linear dynamical model of landing aircraft, that is synthesised via modelling of aircraft structural subsystems using nonlinear multibody dynamics approach. The model includes discontinuous dynamics of main landing gear shock absorber oleo-pneumatic element with fricton, hydraulic and thermodynamic characteristics, non-linear tire contact dynamics and unilateral dynamics of nose gear elastic leg assembly. Several dissipation parameters of oleopneumatic hydraulics are additionally evaluated using CFD numerical methods. The aerodynamic loads are modelled by considering aircraft configurations with landing gear in down position and control surfaces in active/inactive modes.
Developed model and computational procedures allows for dynamic simulation of 3D landing and taxi of large transport aircraft for different flight and landing parameters. Since 'solver' of dynamic simulator is based on numerical processing of nonlinear dynamics of aircraft structural subsystems, modelled as multibody systems (MBS) with variable kinematical structure, its mathematical model is derived as differential-algebraic system (DAE) in descriptor form. The developed numerical tools are modularly shaped and efficient numerical integration methods, as well as original procedures for MBS constraint stabilization, are applied for the aircraft dynamical response determination.
Dynamic simulator is tested via numerical case studies in the framework of which aircraft flight and landing parameters have been varied. Results of dynamic simulations are validated by comparing them to the characteristic values from the aircraft technical documentation, JAA requirements and measured data. Similarly, dynamical characteristics of particular models of several aircraft subsystems are partially validated on the basis of characteristic data. It is planned that the developed computational tools will be utilized within the framework of landing aircraft 'man-in-the-loop' simulation procedures in the sequel of the project.