Static Frictional Contact of the Space Shuttle Nose-Gear Tire

Abstract

Abstract A computational procedure has been presented for the solution of frictional contact problems for aircraft tires. The Space Shuttle nose-gear tire was modeled using a two-dimensional laminated anisotropic shell theory with the effects of variation in material and geometric parameters, transverse shear deformation, and geometric non-linearities included. Contact conditions were incorporated into the formulation by using a perturbed Lagrangian approach with the fundamental unknowns consisting of the stress resultants, the generalized displacements, and the Lagrange multipliers associated with the contact and friction conditions. The contact friction algorithm was based on a modified Coulomb friction law. Elemental arrays were obtained by using a modified two-field, mixed variational principle that was obtained by augmenting the functional of the variational principle by two terms: the Lagrange multiplier vector associated with nodal normal and tangential contact load intensities and a regularization term which is quadratic in the Lagrange multiplier vector. Experimental measurements were made to define the response of the Space Shuttle nose-gear tire to combined inflation pressure loads and static normal loads against a rigid flat plate. These experimental results describe the static load-deflection characteristics of the tire and the normal and tangential load intensity distributions in the tire footprint for the various static vertical loading conditions. Numerical results were obtained for the Space Shuttle nose-gear tire subjected to combined inflation pressure and contact loads against a rigid flat plate. Comparisons were made between the experimental measurements and the numerical results.