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This paper presents a numerical methodology to predict the dynamic behavior of the front end accessory drive (FEAD) and the overrunning alternator decoupler (OAD) pulley. The methodology uses the commercial code Altair Radioss, and is based on 3D Lagrangian formulation, finite element method and explicit time integration schemes. Contact between different parts were considered using penalty methods. The methodology is divided in two independent parts: 1) FEAD with rigid pulleys, and 2) OAD pulley alone with flexible components. In the first part it is possible to evaluate the vibration of relevant components like the belt and the tensioner pulley, and in the second part it is possible to analyze not only the vibration of the OAD pulley, but also the stresses on critical components to durability.

Operational modal analysis is when the modal properties are identified from measured responses only. The modal parameters are: mode shapes (the way the structure moves at a certain resonance frequency), natural frequencies and damping ratios. When modal identification is based on the measured response (output) only, things become more complicated: The excitation (input) is unknown and the measured response (output) is often noisy. In this study, the time domain Stochastic Subspace Identification - Unweighted Principal Components operational modal analysis was applied to the recorded dataset from the durability test conditions of a truck. Using the 40 minutes of road test accelerometer time history in three different road conditions, it was possible to identify the modal parameters and also compare with numerical modal analysis data. Both results presented good correlation.

The powertrain air intake system in internal combustion engines have great effect over power and torque, generally it is designed for high volumetric efficiency, however it is as well an important source of noise with effects over the internal comfort of the occupiers of the vehicle and the pass-by noise. It is known that increasing the transversal sections of the ducts of passage is one of the usual ways to increase the volumetric efficiency of the intake process, but on the other hand, this procedure decreases the capacity of acoustical attenuation generating an increase in the radiated noise. We have here a very conflicting situation, which requires a balance or adjustment of these parameters of project. In these situations the utilization of numerical tools are of great value, for they allow to evaluate and optimize the variables with conflicting effects, especially here the acoustical and fluid dynamical performances. Theses simulations can use 0D/1D and/or 3D numerical tools.