A Dynamic Nonlinear Inertia Relief Formulation

Kurzfassung

In this paper, a method for nonlinear flight-dynamic simulations using the nonlinear transient response analysis in Nastran SOL400 is presented. Since no inertia relief method for large deformations is available in Nastran SOL400, a dynamic nonlinear inertia relief formulation is proposed. Therefore, the inertially coupled structural and flight dynamic equations of motion are employed without the practical mean axes assumption, thus the structural response of a clamped structure can be incorporated. The equations of motion are reformulated to treat the structural responses as inputs rather than states of the system. Furthermore, inertia relief loads are defined in order to incorporate the effects of the rigid body responses in the nonlinear transient analysis in Nastran. The developed method is validated using the equations of motion employing a linear modal approach and using a generic cross beam as a test case.