High-Speed Tyre-Soil Interaction of Aircraft on Soft Runways

A fundamental requirement of military transport aircraft is the ability to maneuver on soft soil runways whereby the flotation depends on the aircraft/runway strength relationship. Hence predictions for the maneuverability, the higher rolling resistance compared to rigid surfaces, and runway damage should be available. These effects depend essentially on the deformation of soil. In the design process of concurrent engineering MBS (Multibody System) simulation tools take an important place. MBS allows investigation of the dynamic behavior of the vehicle, tire and soil system. The simulation of tire-soil interaction by means of multibody tools makes use of analytical modelling and specific measurable parameters are used to describe the physical soil behavior. With analytical approaches for the tire-soil contact area it is possible to reach quite a good approximation for the real contact conditions. The main problems in describing the physical soil behavior are its non-deterministic properties what gives the simulation results, independent from the modelling approach, in terramechanics always quite a great deviation from measurable results. Other approaches treat the problem of tire-soil interaction with the method of finite elements (FE). These finite element models are of very fine discretisation and allow a precise simulation of the deformations of either tire or soil but this modelling approach generally needs a large amount of computation time. From this follows a great advantage of MBS simulation in contrast to FE models that a less detailed model setup is required and MBS models can be calculated on commonly used computer systems quickly. For this reason MBS is very interesting for extensive parameter variations. In addition MBS simulation allows the consideration of the dynamic interaction of aircraft undercarriage and soil and the fuselage can be optionally implemented as flexible body. Presented at RTO Applied Vehicle Technology Panel (AVT) Symposium held in Prague, Czech Republic on 4-7 Oct 2004. Published in RTO-MP-AVT-110, Habitability of Combat and Transport Vehicles: Noise, Vibration and Motion (L'habitabilite des vehicules de combat et de transport: le bruit, les vibrations et le mouvement), p8-1 thru 8-13, 2004. See also ADM201923. The original document contains color images.