Abstract: Based on the geometry, kinematie and dynamie characteristics of landing gear system, the landing impact mechanical model and its initial condition of three dimensional fuselage landing gear with flexural shock strut are presented. The equations of motion and kinematic equations under various landing conditions, including symmetric impact and asymmetric impact are provided. The proposed computational model recognizes that the shock system has four displacements and deformations, i. e. the axial displacement of the shock strut; the structural deformation of the flexual shock strut along fore-and-aft direction; the vertical deflection of the tire; and the fore-and-aft deflection of the tire. The proposed computational model apply modern mechanical knowledge of the tire. The tire vertical force is a function of tire vertical deflection, tire fore-and-aft deflection and tire vertical deflection rate, and involves the following two parameters. (1) Tire vertical load-deflection relation) (2) The vertical damping coefficient. The tire drag force is formulated in terms of tire fore-and-aft deflection and deflection rate. These drag force relations involves the following parameters: (1) Tire fore-and-aft stiffness: (2) Tire fore-and-aft damping coefficient) (3) Coefficient of friction between ground and tires.

Key words: fuselage landing gear, landing impact, flexural shock strut, mechanical model