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Vehicle noise and vibration (NVH) is among the important attributes of the vehicle. This attribute has to be designed for in the product development process. This produces challenges that are usually overlooked by researchers in the field. These challenges are assessed in this manuscript. The emphasis here is on the NVH phenomenon at the vehicle level. Little work is being done to study the vehicle noise and vibration from a system or customer perspective. This manuscript brings to the attention of researchers and the NVH community at large the various NVH challenges that constitute complexities to the development engineer and may deserve closer attention.

This paper presents new analysis methods for brake judder data. First, a distinction is made between Thickness Variation, TV, judder (shudder or roughness) caused by the geometry variation of the brake rotor, and thermal judder caused by thermal caused changes to the friction couple. Spectrograms of vibration signals are used to distinguish between the two types of judder. Instrumentation of vehicles in order to get significant data is also provided. A linear model is used to describe the mechanism of judder generation. Different case studies are provided. Special tools of analysis like spectrograms, power time and spectral densities, and zero crossing frequency estimates are applied to real data.