N&V Component Structural Integration and Mounted Component Durability Implications

Exterior component integration has presented competing integration challenges for suitable exterior styling, safety, N&V structural feel and component durability balanced performances. Industry standard practice of N&V vehicle mode mapping uses vehicle source, path and receiver considerations for component mode frequency placement. Mounted component mode frequency performance can have an influence on structural feel and durability performances. Component integration headwinds have increased with additional nonstructural component styling content, component size, component mass and added sensor modules. Based on first principles, the effective mass of exterior mounted components are increased due to the geometric overhang from structure. Component input vibration levels are compounded due to the cantilevered nature as well as relative positioning to the suspension and propulsion vehicle source inputs locations. Examples of vehicle end mounted components include but are not limited to headlamps, side mirrors, end gates, bumpers and fascia. Our goal is to establish basic expectations for the behavior of these systems, and ultimately to consolidate our existing rational and approaches that can be applied to such integrated systems. The focus of this paper will consider a simple two degree-of-freedom system subject to a base excitation. Both masses will be attached via springs and dampers, and we will restrict ourselves to a linear model for simplicity. Component mode decoupling, vibration ratio amplification and basic design guidance relationships are established from simple model studies.