Define general taxonomy (classification) of the most common fixture designs. Provide general design, fabrication, and installation guidelines to improve repeatability, reproducibility of vehicle conditions (including preloading) of brake fixtures for inertia dynamometer NVH testing.
Brake testing for noise, vibration and harshness using inertia dynamometer tests is one of the most prevalent types of laboratory testing across the automotive industry. Decades of inertia dynamometer testing in multiple regions have led to multiple fixture design philosophies and methodologies, with substantial effects on the test results. In addition, in the current landscape of the automotive manufacturing industry, vehicles are designed in one location, manufactured at another location(s), and sold all over the world with significant differences in environmental conditions during their life cycles. Efforts to reproduce vehicle-level conditions and environmental factors in the laboratory setting lead to redundancy, conflicting results, or high-variability in test results of the same test program. This Information Report provides the industry with a systematic overview of the main types of fixture designs as a function of: a) the level of hardware involved, b) the preloading method, and c) type of frame utilized to adapt the vehicle/brake assembly to the dynamometer. This IR also includes guidelines for best practices regarding fixture fabrication, verification, and installation on the inertia dynamometer test chamber.