DYNAMICS OF MULTIBODY TRACKED VEHICLES USING EXPERIMENTALLY IDENTIFIED MODAL PARAMETERS

The mode shapes, frequencies, and modal mass and stiffness coefficient s of multibody systems such as tracked vehicles can be determined usin g experimental identification techniques. In multibody simulations, ho wever, knowledge of the modal parameters of the individual components is required, and consequently, a procedure for extracting the componen t modes from the mode shapes of the assembled system must be used if e xperimental modal analysis techniques are to be used with general purp ose multibody computer codes. In this investigation, modal parameters (modal mass, modal stiffness, modal damping, and mode shapes), which a re determined experimentally, are employed to simulate the nonlinear d ynamic behavior of a multibody tracked vehicle which consists of inter connected rigid and flexible components. The equations of motion of th e vehicle are formulated in terms of a set of modal and reference gene ralized coordinates, and the theoretical basis for extracting the comp onent modal parameters of the chassis from the modal parameters of the assembled vehicle is described. In this investigation the track of th e vehicle is modeled as a closed kinematic chain that consists of rigi d links connected by revolute joints, and the effect of the chassis fl exibility on the motion singularities of the track is examined numeric ally. These singularities which are encountered as the result of the c hange in the track configuration are avoided by using a deformable sec ondary joint instead of using the loop-closure equations.