Multi-body dynamics for the assessment of engine induced inertial imbalance and torsional-deflection vibration

Use of multi-body dynamics is increasing in the area of powertrain NVH analysis. This growth is much owed to a need for vehicle refinement in the area of engine induced vibration and the often associated structure-borne noise. In recent years the trend has been in the development of engines with high output power to weight ratio, through use of materials of lighter construction and with a greater power torque. Thus, component flexibility has been playing a greater role in system dynamics. The paper presents a multi-body approach for the determination of sources of powertrain Noise, Vibration and Harshness (NVH) by paying particular attention to crankshaft system elastodynamic behaviour that contributes significantly to half-engine order vibrations.