Rethinking aluminum for NVH abatement

Engineers, abandon those mastics! New “quiet” materials solutions are at hand.

Engineers who have witnessed aluminum-intensive vehicles being “uncloaked” in a full competitive teardown relate the same story: After you've pulled the carpet out and stripped it down to the naked bodyshell, the “band-aids” are clearly exposed-typically on the floorpan, bulkheads, on the rear package tray of sedans, around the wheelhouses, and within the noise-critical dash panel and cowl plenum.

Band-aids are a form of NVH triage. These bake-hardenable butyl materials, cavity-injected foams and the like are added to the body structure and exterior panels to dampen noise. Such countermeasures are often added late in development, after production tools are released and the vehicle on-sale date looms. But they're also employed after production launch, as a solution to customer complaints about unacceptable resonances and road noise.