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High mileage NVH performance is one of the major concerns in vehicle design for long term customer satisfaction. Elastomeric components such as suspension bushings, engine mounts and tires function as vibration isolators in a vehicle. High mileage tends to cause the degradation of these components which in turn affects vehicle overall NVH performance. The present paper discusses the characteristics of bushing degradation based on laboratory bushing test data. Vehicle subjective evaluation and CAE modeling methods are used to develop a fundamental understanding of the effects of bushing degradation on vehicle NVH performance. The concept and analysis methodology are demonstrated using the front and rear suspension strut mounts and tire inputs which simulate road excitations but they are valid for other elastomeric components such as engine mounts and excitations. The knowledge derived in the study can be used as a generic guideline in designing vehicles for high mileage NVH robustness.

Friction behavior is one of the most critical factors in brake system design and performance. For up-front design and system modeling it is desirable to be able to describe a lining's frictional behavior as a function of the local conditions, such as contact pressure, temperature and sliding speed. Typically, frictional performance is assessed using brake dynamometer testing of full-scale hardware, and an average friction value is used during brake system development. This traditional approach yields an average brake friction coefficient that is hardware-dependent and fails to capture in-stop friction variation; it is also unavailable in advance of component testing, ruling out true up-front design and prediction. To address these shortcomings, a scaled inertial brake dynamometer was used to determine the frictional characteristics of candidate lining materials.