Dynamic analysis of coupling elements in IC engine test rigs

This work regards the dynamic analysis of the coupling elements in IC engine test rigs from a numerical and experimental standpoint. Two mathematical models of an IC test rig have been developed: a torsional lumped-parameter (LP) model (developed in Matlab-Simulink) for the estimation of the torsional dynamic behavior and a 3D finite element (FE) model for the estimation of the natural frequencies of the coupling elements. The numerical models take into account the stiffness and damping of the flexible elements as well as the test rig inertia properties. A large experimental campaign has been carried out in order to validate the models. In particular, torsional vibration measurements have been achieved by a coder-based technique using high-quality optical sensors and equidistantly spaced markers (zebra tape) on the rotating components (high flexible couplings). Eventually, the validated models have been used in order to evaluate the effect of design modifications of the coupling elements in terms of natural frequencies (torsional and bending) and torsional vibration amplitude.