NVH Powertrain Dynamics: Multibody Simulation and Correlation with an Integrated Approach in Virtual.Lab/Motion

摘要

This paper presents the results of a test - CAE comparison for a powertrain in terms of vibrations and crankshaft irregularities performances. The engine used in the activity is a 1.9 liter JTD 16 valves (4 cylinders). These results show an excellent correlation proving the validity of the chosen CAE approach to model the powertrain. The CAE model used to analyze the powertrain performances is a complete multibody model developed in the LMS Virtual.Lab/Motion environment, including the crankshaft, the engine block and the torque rod, which have been implemented as flexible parts, in order to guarantee the correlation results. The engine has been implemented in LMS PDS (Powertrain Dynamic Simulator) environment and then exported in LMS Virtual.Lab/Motion. Correlation results have been achieved with a structured modeling approach. Improved correlation can be reached by tuning modal damping values for the most important modes involved in the dynamic behavior of the model. A reduced and confident model has been performed in order to decrease the model size and accelerate the CPU time of the analysis. Availability of a correlated model in multibody environment represents a key factor in the powertrain design, allowing designers to frontload most of the NVH performances with good confidence even during Concept Phase of the development timeline.