Simplified Modelling of Vehicle Interior Noise: Comparison of Analytical, Numerical and Experimental Approaches

Abstract

The present paper describes the results of the investigation of low and medium frequency vehicle interior noise carried out using simplified structural-acoustic models. Analytical, finite element (FE) and experimental studies are presented and compared. In particular, the analytical approach is based on the formula representing the interior acoustic pressure in terms of structural and acoustic normal modes. This procedure does not take into account the effect of the enclosed air on structural vibrations. The FE analysis considers structural vibration modes, interior acoustic modes, full structural-acoustic interaction and the resulting structure-borne noise. The above-mentioned analytical and numerical results are compared with each other, and both of them are compared with the experimental results obtained for the simplified reduced-scale vehicle model "QUASICAR" developed in Loughborough University. The comparisons demonstrate some specific features of the analytical and numerical approaches and outline the acceptable limits of simplification in modelling vehicle interior noise. Although this study is concerned with structure-borne vehicle interior noise, its results and conclusions could be of interest for a wider range of engineering problems, such as building acoustics and dynamics of thin shell structures.

Evaluation and Optimization of the Aerodynamic Noise Reduction of Vehicle Side View Mirrors: Experimental and Numerical Study

“…As can be seen in these pictures, the turbulent zone in the back of the modified mirror is smaller than the current mirror due to the reduced area of fluctuating pressure. As with other efforts, the maximum velocity zone is located on the edge [3,[19][20][21][22][23][24]. The maximum speed of the modified was 44.3 m/s, while this value was 60 m/s for the current Tiba mirror.…”

Engine noise cancellation with optimum array of speakers inside vehicle enclosures

“…As shown in Figure 1, the vehicle is a cubic cavity with a flexible plate on one side (the one in contact with the engine) and rigid plates on the remaining sides. From a modeling standpoint, this is a quite popular approach adopted in many different studies to estimate acoustic field properties in vehicle cabins (see Georgiev et al, 2006; Jha, 1976; Wang, 2010). Since the engine force are dependent to the engine working RPM, it imposes harmonic forces on the connected points to the front flexible plate causing pressure fluctuations (Wu et al, 2019).…”

A new method for location of the main contribution modes by the decomposed sound pressure

“…Krylov (2002) developed a simple analytical model for computing the interior sound pressure of a car structure-acoustic coupled system using mathematical formulas. Based on this simple analytical model, Georgiev et al (2006) presented the coefficient of structure-acoustic coupling and pointed out that the coefficient depends only on the geometrical coincidence between the structural and acoustic mode shapes on their contact surfaces, and the higher values of the coupling coefficient are associated with the spatial similarity between structural and acoustic mode shapes. Dong et al (2011) and Gao and Deng (2011) extended the application of the coefficient of structure-acoustic coupling (also named the mode shape coupling coefficient) in the works of Georgiev et al (2006) to arbitrarily shaped structure-acoustic coupled systems and pointed out that the key factors of the mode shape coupling coefficient are the mode shape similarity and the mode shape complexity between structural and acoustic mode shapes on their contact surfaces; the higher the similarity and the lower the complexity, the larger the coefficient, which is the mechanics of structure-acoustic coupling.…”

“…Since the mechanics of structure-acoustic coupling are clear to a large extent (Dong et al, 2011; Fahy and Gardonio, 2007: 415–427; Gao and Deng, 2011; Georgiev et al, 2006), research emphasis turns to methods to locate the structural and acoustic modes of the main contribution. Then, with the mechanics of structure-acoustic coupling, structural modifications can be proposed quickly with the aim of reducing the structure-borne noise inside cavities.…”