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For purposes of reducing development time, cost and risk, the majority of new vehicles are derived strongly or at least generally from a surrogate vehicle, often of the same general size or body style. Previous test data and lessons learned can be applied as a starting point for design of the new vehicle, especially at early phases of the design before definite design decisions have been finalized and before prototype of production test hardware is available. This is true as well of vehicle NVH development where most new vehicles being developed are variants of existing vehicles for which the main noise transfer paths from sources of interest are already understood via test results and existing targets. The NVH targets for new vehicles are defined via benchmarking, market considerations, and other higher-level decisions. The objective is then to bridge the gap between test data from surrogate vehicles to direct support of the NVH development of new vehicle programs.

The development of new technologies that reduce engine size and improve performance, combined with the introduction of hybrid and electric vehicles, make tire noise critically important for the new generation of automobiles. Tire noise transmission into the passenger compartment can be classified as either air-borne or structure-borne sound. Both of these mechanisms are very complex to predict because tires are highly non-linear, subject to large static, dynamic and centrifugal loads; they suffer from impact, stick and slip forces; and the pumping of air in the tire grooves is complicated. Customers today demand more sophistication of products in terms of interior noise; thus, sound quality metrics have earned an important role during the design phase allowing human perception of noise to be predicted and improved with reduced cost in a way that addresses consumer preferences.

The early design phase of vehicle development is a challenge for NVH because test hardware is not yet available. Surrogate test data may be available and can be combined with best engineering practices to make design decisions, but accurate prediction capability for modeling NVH effects of proposed changes for new vehicles programs is valuable. SEA is a mature CAE technology for NVH development in the automotive industry worldwide, particularly for airborne noise predictions and at higher frequencies (above 200 Hz). Unlike FEA and deterministic modeling techniques, SEA accuracy relies on a good characterization of acoustic absorption, structural damping, and details of flanking paths, particularly leakage. However, an SEA model correlated to test data that isolates the contribution and mechanisms of each of the dominant paths is a resource that can be used for early design phase NVH predictions of noise transfer paths.