Linear and Nonlinear Models for Drop Simulation of an Aircraft Landing Gear System with MR Dampers

In this study, our focus is on the drop test simulation of an MR (Magnetorheological) damper-based main landing gear (MRMLG), aiming to explore multi-degree-of-freedom (DOF) dynamic models during aircraft landing. Three different 6-DOF dynamic models are proposed in this work, and their drop performances are compared with results achieved by commercial software. The proposed models include a nonlinear aircraft model (NLAM); a linearized approximated aircraft model (LAAM) linearizing from the nonlinear equations of motion in NLAM; and a fully approximated aircraft model (FAAM) which linearizes the MRMLG's strut force model. In order to evaluate the drop performance of the aircraft landing gear system with MR dampers, a 7-DOF aircraft model incorporating the nonlinear MRMLG was formulated using RecurDyn. The principal comparative parameters are the coefficient of determination (R-2) for the system response of each model with the RecurDyn model and root mean square error (RMSE), which is the ensemble of CG displacement data for each model. In addition, the ensemble of time series data is created for diverse drop scenarios, providing valuable insights into the performance of the proposed drop test models of an aircraft landing gear system featuring MR dampers.