3.1.4 Noise, Vibration and Harshness (NVH)

While the term NVH is common in automotive manufacturing, unwanted NVH is prevalent in many other industries as well. Using adhesives over traditional joining methods contributes to reducing the noise generated by motors in vehicles, ships, aircraft and industrial machinery, allowing for silent operation of home appliances, such as dishwashers and refrigerators, or reducing vibration and associated rattling within air conditioning systems. Such reductions to ambient noise are becoming more routine, with many new designs using adhesives and sealants to achieve these operating characteristics. NVH products are typically designed for use within vehicles or for adhering to substrates used in automotive manufacturing (steel, aluminium, composites, etc.). These principles apply to the manufacture and operation of all appliances within any sector where there is a desire to minimise noise.

Some adhesives are designed to address NVH challenges, rather than physically blocking sound waves and generally behaving as an insulator. They are naturally viscoelastic and dampen sound by absorbing sound energy. For example, structural adhesives cure rigid materials and create solid connections that bond individual pieces or components to each other or a structure. In such instances, vibrations produce less sound energy, as they cannot move the bonded parts separately from one another; this reduces rattling noises (noise and vibration) and can extend the lifetime of a product.

The ability to accommodate or mitigate noise and vibration is essential when consistent impacts or shaking are expected during the operation of an assembly. Threadlockers also contribute to overall NVH performance by bonding threaded fasteners and resisting vibrational loosening and corrosion. Washing machines, dryers and other appliances subjected to high-frequency vibrations are good examples of where threadlocking adhesives help to augment the NVH performance of structural or gap-filling adhesives. Using rigid and elastic adhesives for strong connections or void filling, as appropriate, will contribute to reducing the overall noise generated, potential vibration and degrading effects of these harsh impacts.