Numerical Simulation of Landing Aircraft Dynamics

Preliminary note Numerical simulation procedures for landing dynamics of large transport aircraft are briefly presented. Developed numerical procedures allow for determination of dynamic response of landing aircraft for different flight and touch-down parameters. A non-linear dynamic model of landing aircraft, which serves as a basis for computational procedures, is synthesised by modelling of aircraft structural subsystems using a multibody dynamics approach. A dynamic model with variable kinematical structures includes discontinuous dynamics of landing gear oleo-pneumatic shock-absorber with friction and hydraulic/thermodynamic processes. Non-linear tire contact dynamics and unilateral dynamics of nose gear elastic leg assembly is modelled as well. The longitudinal and lateral aerodynamic loads are estimated by considering various aircraft system configurations (landing gears in “up’’ and “down’’ position, different control surfaces in active/inactive modes). A mathematical model is derived as a differentialalgebraic (DAE) system. The developed numerical tools are modularly shaped and efficient numerical integration methods as well as original procedures for MBS constraint stabilization are applied for dynamic response determination. On the basis of the presented model, dynamic simulations of landing cases of large transport aircraft were performed for different initial descent velocities with focus on determination of dynamical loading of main landing gear assembly.