Exhaust Manifold Radiation in the 5 kHz Range:Prediction of Structural and Interior Acoustic Excitation NoiseRadiation of an Exhaust Manifold

摘要

A vibro-acoustic CAE study of an exhaust manifold radiation in the 5 kHz frequency range is presented.LMS Virtual.Lab features for vibro-acoustic analysis are used to predict the separate contributions to the structural vibration and the noise radiation of the two excitation sources: structural, from the engine through the engine to manifold connections, and interior acoustic, from combustion and exhaust valves.Scope of the study is to understand the noise excitation mechanisms and to establish a standard procedure to simulate the vibro-acoustic behavior of a steel-sheet exhaust manifold up to middle-high frequencies, with special focus on FE model updating based on measurements.Paper shows that the methodology applied gives good results starting from a pure CAE approach, allowing designers to frontload most of the NVH performances with good confidence even during the Concept Phase of the development timeline.