Dynamics of Inertia-Variant Flexible Systems Using Experimentally Identified Parameters

In this investigation modal parameters (frequency, damping, and mode shapes) which are determined experimentally using parameter estimation techniques are employed to simulate and predict the dynamic behavior of flexible multibody systems which consist of interconnected rigid and flexible components. The system differential equations of motion and algebraic constraint equations describing mechanical joints in the system are first identified using analytical techniques. Dynamic parameters such as mass, damping, and stiffness coefficients that appear in the system differential equations are then identified using a set of experimentally measured data. Mode shapes which are the result of the experimental identification are used to write the physical elastic coordinates of selected nodal points on the flexible body in terms of a reduced set of modal coordinates. The nonlinear differential and algebraic constraint equations are then written in terms of mixed sets of coupled reference and modal coordinates. These equations are integrated numerically using a direct numerical integration technique coupled with Newton–Raphson type iterations in order to check on constraint violations. The formulation developed is numerically exemplified using a three-dimensional dune buggy vehicle model.