for Automotive NVH Management
Noise refers to unwanted sound both inside and outside the vehicle; vibration refers to mechanical oscillation, and harshness to the severity or discomfort of the noise and vibration.2 NVH affects the overall perception of cars and trucks, and is considered an important factor in vehicle design.
High levels of vibration and noise can be hazardous for occupants over long time scales, but reducing NVH helps to produce quieter, more comfortable vehicles.2 Furthermore, reducing NVH in vehicles helps to reduce environmental noise pollution, which has been linked to sleep disturbances and increased cardiovascular risk.3,4
The first NVH studies were applied to reduce noise and vibration from the engine, as this was the biggest source of noise in the vehicle. As the level of noise from the engine has been significantly reduced over decades of car development, other sources of noise like braking noise, road noise, and aerodynamic noise have become more important.
The engine and engine accessories are also significant sources of vibration in vehicles, along with the drivetrain and wheels.1,5 Automotive manufacturers must consider all sources of noise and vibration, and design their vehicles to reduce the effects of NVH using innovative materials and clever engineering.
Advanced Acoustic Insulation Materials Reduce NVH in Vehicles
Early attempts to reduce noise consisted of filling panels in doors floors and roofs with as much insulation as possible to reduce rattling. Now automotive panels are precisely designed to provide acoustic performance, and advanced acoustic materials are utilised to reduce NVH.
Recent advances in materials science have produced significant improvements in the performance of sound absorbing materials, and as a result, a wide range of acoustic materials are commercially available, including natural fibres, biopolymers, recycled materials, porous metals, composites and smart materials.6,7,8
The various types of available acoustic insulation materials all provide high sound absorption coefficients, but their exact performances vary depending on sound frequency, material composition, thickness, finish, and mounting methods. Sound absorbing materials typically consist of solids with cavities or channels that trap air, allowing sound waves to enter the material. 6,7,8
When the sound waves enter the material, the fibres of the material begin to vibrate. The vibration causes the fibres to rub against each other, resulting in heat from friction. In this way, the energy from the sound vibration is converted to heat that dissipates.9
Tecman Provide a Range of Bespoke Acoustic Insulation Solutions
The majority of commercially available sound-absorbing materials are fibre based, as fibrous provide cavities between the fibres that allow sound waves to enter. The fibres can move against each other, allowing the energy of the sound waves to be converted to friction easily.
Tecman provides acoustic insulation pads made using a range of fibrous acoustic insulation materials. Although the properties of the individual materials vary, automotive insulation solutions from Tecman are all designed to provide highly efficient acoustic absorption while reducing the weight and environmental impact of vehicles. The acoustic materials provided by Tecman include lightweight ultra-fine fibre, multi-layer fine fibres, high-loft insulation, and needle punch materials.10,11
ALFA® Technology Acoustic & Thermal Insulation Series is the most recent range of advanced NVH materials introduced into Tecman’s product portfolio. Providing superior levels of automotive NVH reduction, ALFA® Technology includes sophisticated multi-layer laminates, advanced scrim materials, impregnated layers, & ultra-lightweight heat reflective materials which provide a high degree of flexibility when developing bespoke NVH management solutions.12
Past investment in new machinery and processes provide an increased capacity and larger part sizes of acoustic insulation components. The current machinery stamps out parts up to 520mm x 1500mm (previous capacity was 320mm x 1000mm). Bespoke components are available in various presentation formations to aid application. Presentation options include sealed, crimped and open edges, tape application, strip coated adhesive, zone coated adhesive, clip insertion, scrim variations, and scrim lamination.12
Tecman has been providing advanced solutions for the automotive industry for over 25 years, and their clients already include some of the leading original equipment manufacturers and tier-one suppliers across Europe and beyond. Recent investments in their conversion facility further increases their ability to provide bespoke acoustic insulation solutions to the automotive industry that help to combat NVH.
- Panza MA, ‘A Review of Experimental Techniques for NVH Analysis on a Commercial Vehicle’ Energy Procedia 82:1017-1023, 2015.
- Ab Aziz SA, Sohaimi RM, Pu’ad MH, Mohd Yaman MA, ‘Noise, Vibration and Harshness (NVH) Study on Malaysian Armed Forces (MAF) Tactical Vehicle’ Applied Mechanics and Materials, 165:165-169, 2012
- Jakovljević B, Lojević G, Paunović K, Stojanov V, ‘Road traffic noise and sleep disturbances in an urban population: Cross–sectional study.’ Croatian Medical Journal 47(1):125-33, 2006.
- Babisch W, ‘Transportation noise and cardiovascular risk: Updated review and synthesis of epidemiological studies indicate that the evidence has increased.’ Noise and Health, 8(30):1-29, 2006.
- http://www.autoserviceprofessional.com/article/93006/noise-vibration-harshness-chasing-the-irritant-gremlins Accessed July 12th, 2017.
- Al-Zubi M, Ayorinde E, Alshabatat N, Dundar M, Murty Y, ‘Sound and vibration considerations of some materials for automotive engineering applications’ American Journal of Applied Sciences 11(10): 1784-1797, 2014.
- Mohanty AR, Acoustical Materials for Automotive NVH Reduction. In: Munjal M.L. (eds) IUTAM Symposium on Designing for Quietness. Solid Mechanics and Its Applications, vol 102. Springer, Dordrecht, 2002.
- Arenas JP, Crocker MJ, ‘Recent trends in porous sound-absorbing materials’ Sound & Vibration 44:12-17, 2010.
- https://www.acousticalsurfaces.com/acoustic_IOI/101_7.htm Accessed July 12th, 2017.
- http://www.tecmanuk.com/industry/industries/automotive/automotive-acoustic-solutions/ Accessed July 12th, 2017.
- http://www.tecmanuk.com/news/importantance-of-nvh-reduction/ Accessed July 12th, 2017.
- http://www.tecmanuk.com/product-services/products/foams-nonwoven/nonwoven-materials/acoustic-insulation/ Accessed November 16th 2018.