8. Multi-body-Simulation of a Self Adaptive Torsional Vibration Absorber

Automotive manufacturers try to decrease emissions and fuel consumption by downsizing the engine. This means the number of pistons and the swept volume are reduced. Unfortunately, this increases the vibrations which are caused by the oscillating movement of the pistons. The vibrations are transferred through the power train and the car body to the passenger seats. To reduce these vibrations absorbers are installed into the power train. In this paper a vibration absorber is simulated by general purpose multi-body simulation software. Swing arms which are clamped to a disc in radial direction are modelled as flexible bodies. Each swing arm has got a mass at its end which is in form of a rigid body. Because of the centrifugal force which increases the geometric stiffness of the swing arms, the vibration absorber’s eigenfrequency continuously adapts to the current engine rotational speed. Thus the adaptive vibration absorber is able to reduce vibrations from idle up to maximum speed. The paper describes the multi-body system with flexible bodies, the linearization of the nonlinear equations of motion and the results of a parameter study.