Modeling And Analysisof The Powertrain Mounting System Based On Rigid Body Dynamics

With the development of the living standards, people pay more and more attention to the ride comfort ofvehicles. Thusthe noise, vibration, and harshness(NVH) optimization becomes an important aspect in modern vehicle design. The powertrain, as the main vibration and noise source, has attracted the attention of NVH engineers. The powertrain isolation is mainly realized through powertrain mountingsystem(PMS), which is composed of powertrain and supporting elements. the PMS also plays a role of limiting displacement of the powertrain. Analysis of the PMS includes dynamic response analysis and static analysis. The dynamic modeling of PMS can directly affect the accuracy of analysis results.At present, linearized model, which is based on small angle assumption, is mostl y adopted in the process of the PMS analysis. The vibration model is simple and easy to solve. However, as the rotational angle of powertrain increases, the small angle assumption becomes irrational, and the precision of model decreases. This thesis focuses on dynamic modeling of PMS, with following items researched:? Main components of PMS excitation are analyzed. The powertrain inertia parameters are obtained by experimental technique.. Criteria for optimum design of PMS are concluded.? Two types of PMS models are constructed by the use of Lagrange equation, vibration model based on small angle assumption and model based on rigid body dynamicstheory, followed by algorithmic implementation in Matlab software.? Through numerical applications, the differences between these two models are investigated in detail. Main factors which lead to such differences are analyzed by the use of design of experiment(DOE) technique.