Pneumatic tire model for aircraft simulation

The development of a tire model for the prediction of vertical and drag loads in response to large discrete surface obstacles shorter than the tire footprint length is presented. The tire is modeled as a toroidal membrane with the objective of characterizin g the enveloping properties of the tire. An explicit set of equations is used to calculate the tire footprint in contact with a user specified surface profile, the tire volume, the pneumatic pressure, and the resultant vertical and drag loads at the wheel axle. Tire carcass and bottoming loads are also predicted. The model is designed to be computationally efficient for use with aircraft digital taxi simulations. Model predictions are compared with tire test data for low-speed fixed axle excursions over short rectangular bumps and dips. Excellent quantitative correlation is demonstrated.