Noise, vibration, and harshness (NVH), also known as noise & vibration (N & V) is the study and modification of the noise and vibration characteristics in numerous industries such as automotive, aerospace, appliance, structural, and transportation. NVH issues often occur with items in the above industries that open and close, slide, tilt, vibrate, shake, and twist.
Many problems are generated as either vibration or noise, transmitted via a variety of paths, and then radiated acoustically. These are identified as structure-borne noise while others are generated acoustically and propagated by airborne paths. Structure-borne noise is attenuated by isolation, while airborne noise is reduced by absorption or through the use or barrier materials.
There are three ways of improving NVH:
- Reducing the source strength, as in making a noise source quieter with a muffler, or improving the balance of a rotating mechanism.
- Interrupting the noise or vibration path, with barriers (for noise) or isolators (for vibration).
- Absorption of the noise or vibration energy, as for example with foam noise absorbers, or tuned vibration dampers.
There are various adhesive and film product offerings used to mount NVH materials for such applications as vibration & acoustical dampening, anti-rattle squeak, sound attenuation, assembly, and structural bonding to name a few.