In order to reduce development time and costs, application of numerical prediction techniques has become common practice in the automotive industry. Among the wide range of simulation applications, prediction of the vehicle interior noise is still one of the most challenging ones. The Finite Element Method (FEM) is well known for acoustic predictions in the low-frequency range.
As part of the development of a full sized bus model, noise levels at Driver Ear Levels (DEL) and Passenger Ear Levels (PEL) were targeted. The structural and acoustic analysis were performed for a bus to reduce interior noise in the low-frequency range. Various counter measures were identified and structural optimization/modifications were performed from virtual simulation to reduce the DEL and PEL.
Structure-borne noise due to both road-induced vibration and engine vibration were considered by using FEM techniques. The coupled analysis between vibration of the vehicle structure and acoustics of the interior cavity was performed.
The analysis has been carried out to find out the various parameters which affects the interior noise & vibrations viz. Noise transfer function (NTF), Structural Modal participation factor (SMPF), and panel participation factor (PPF) at various excitation & response points for critical frequencies.