Numerical investigation of a landing gear system with PIN joints operating clearance

In this paper, FE method is applied to determine an operating clearance influence on the dynamics of a military transport aircraft landing gear. The numerical analysis results presentation of two-dimensional landing gear model drop tests using MSC Working Model code is also shown. Numerical results agree well with respective experimental investigation ones. The analyses using two-dimensional rigid model were performed to correlate a numerical characteristic of a shock absorber substitute model with real shock absorber characteristic. A fully deformable spatial discrete FEM model of the landing gear was developed for precise analyses aimed at determining a joint clearance influence on a considered mechanical system dynamics. Calculations were performed using the so-called direct-integration procedure, colloquially called 'the explicit integration'. Additionally at this stage, the Rayleigh damping model has been included. The non-linear dynamic analyses were performed using the LS-DYNA code. The final part presents the comparison of drop tests numerical solution results of a landing gear with assembly clearance and with operating clearance. The advantage of developed numerical method is the possibility to determine energy changing, particular components deformations, joint contact forces, what is nearly impossible to record performing experimental investigation. The presented method is applicable for a variety of boundary condition i.e. drop velocities, aircraft effective mass, etc.