Application of Flexible Multi Body Dynamics (MBD) and Finite Element Analysis (FEA) for Powertrain Induced NVH Development of a Vehicle 2011-26-0016

Control of powertrain radiated noise and of excitations induced by the Powertrain through the mounts are key aspects towards designing the Powertrain induced NVH performance of a vehicle. During the concept, as well as later stages of Powertrain development, use of simulation tools for MBD, FEA and Vibro-Acoustics can help to evaluate and lead the Powertrain design decisions. In the present work, the flexible MBD software packages, AVL-Excite and MSC-NASTRAN, have been used to predict upstream mount vibrations and surface vibrations of the Powertrain structure. The radiated sound pressure was predicted using LMS Virtual Lab software. In MBD simulation of the Powertrain, the linear elastic Powertrain components (Crankcase, Cranktrain, Drivetrain, etc.) were FE modeled and condensed using MSC-NASTRAN; condensed linear elastic Powertrain components were then connected by means of non-linear joints at the bearing locations. The simulated Powertrain MBD model was then forced using measured p-theta information.

Correlation of predicted vs. measured test results is discussed for the vibration responses at a few points on the surface of the Powertrain and on the active side of the mounts. In addition, the calculated sound pressure levels at standard microphone locations around the Powertrain are also compared to measurements. Following the success of this correlation, the validated process was utilized for optimizing the design of a new Powertrain during its initial development stages.