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A quiet passenger compartment is highly desired by today's customers. Vehicle design teams spend significant time and resources to minimize the vehicle's interior noise due to different exterior noise sources. Drive-by vehicles on the highways generate one of these noise sources. The objective of this study is to establish a correlation between customer's on-road experience due to drive-by noise and Noise Reduction Level (body transparency) tests conducted in a reverberation room. The average Noise Reduction Level (NRL) obtained in the reverberation room tests correlates (R2=0.89) with the peak loudness of on road tests. A sound quality listening study was also conducted to determine the most preferred NRL spectral distribution and its frequency range sensitivity.

At low frequencies, the finite element method reliably predicts the dynamic response of structures. At high frequencies where modal density is high, statistical energy analysis (SEA) is a useful tool to determine the global dynamic behavior of the structures. SEA gives only the space frequency band averaged energy for each subsystem. In the mid-frequency range where both short and long waves are present, neither low nor high frequency approximation to the dynamic response is valid. In this frequency range, there is a need to utilize another technique to capture the dynamic response of the structure. In this study, the energy finite element analysis (EFEA) method is evaluated as a possible technique to close the mid-frequency analysis gap related to NVH analyses. EFEA gives spatial variations of energy density and power in each subsystem, and models localized damping treatment and localized power input.

A finite element-based acoustic-structure interaction analysis tool has been developed to determine the noise transmission loss characteristics of door seal systems. This tool has been applied to determine the effects of the individual parameters, such as seal material density, seal constitutive model, separation distance between seal layers, external cavity shape, and seal prestress field, on noise transmission characteristics. Our findings indicate that the external and internal cavity shapes, seal material density, and deformed seal geometry are the key factors affecting the noise transmission through seal system. Increasing seal material density decreases the resonance frequencies and increases the overall sound transmission loss. Changing the separation distance between seal layers changes the sound transmission characteristics without changing the compression load deflection behavior of the seal system.

The Multi Material Lightweight Vehicle (MMLV) developed by Magna International and Ford Motor Company is a result of a US Department of Energy project DE-EE0005574. The project demonstrates the lightweighting potential of a five passenger sedan, while maintaining vehicle performance and occupant safety. Prototype vehicles were manufactured and limited full vehicle testing was conducted. The Mach-1 vehicle design, comprised of commercially available materials and production processes, achieved a 364 kg (23.5%) full vehicle mass reduction, enabling the application of a 1-liter 3-cylinder engine resulting in a significant environmental benefit and fuel reduction. This paper includes details associated with the noise, vibration and harshness (NVH) sound package design and testing. Lightweight design actions on radiating panels enclosing the vehicle cabin typically cause vehicle interior acoustic degradation due to the reduction of panel surface mass.

With the continuing challenges of future fuel economy targets carbon fiber composite materials are one facet of a lightweighting strategy to enable reduced fuel consumption. In general, use of lightweight materials such as carbon fiber composites in vehicle design generates vehicle NVH performance degradation. To address this potential issue at the design phase, there is a need to develop correlated CAE models for carbon fiber vehicle parts to evaluate the NVH impact of carbon fiber composite material use in vehicle design. To develop correlated CAE models for lightweight vehicle design with the use of carbon fiber composite vehicle body parts, an experimental study was conducted to determine the material and NVH characteristics of the carbon fiber composite materials. In this paper, the damping properties and NVH modal analysis results for structural carbon fiber thermoset composite panels and body parts (B-pillar upper insert and B-pillar lower insert) is presented.