OEM&Lieferant Ausgabe 1/2020

106 Lightweight Ultralight – Low areal weight products to improve the acoustic performance of modern cars By Bernd Fuhrmann, Global Product Manager, Sika Automotive With governments setting stronger CO 2 emissions standards and consumers demanding better fuel efficiency, building lighter cars is of critical importance for OEMs. To achieve this, engineers are choosing non-traditional ma- terials such as aluminum, magnesium and carbon fiber reinforced plastics. Lighter gauge metal sheets are also being used, but these materials create unique challenges in vehicle assembly processes and introduce unwanted effects on durability, acoustics, vehicle dynamics and crash performance. This is when new innovative damping materials come into play, they allow manufacturers to obtain better acoustic performance all the while offering a lower area density than typical structure born noise damping products. Structure-borne sound attenuation is of great importance for the car industry A modern car has to be able to respond to customers’ expectations regarding comfort in NVH behavior (NVH: Noise, Vibration, Harsh- ness). Through technological transformation towards drive electrification and autonomic riving, new challenges also emerge in the area of attenuation of structure-borne noises. Attenuation of mechanical energy taken from a vibrating system is usually transformed into heat. In this way, waves in the structure be- come weakened and amplitude in resonance areas is reduced. The usual method to accom- plish this includes the application of materials characterized with very good damping prop- erties. Necessary conditions include design optimization as well as knowledge of the vi- brational behaviour of the car gained from sim- ulations or laser vibrometry studies targeted at the reduction of vibrations as well as knowing the damping properties of the used material in various frequency and temperature ranges. Application of attenuation material on the vehicle body constitutes an essential tool to improve acoustic comfort and thus subjective assessment of vehicle value. Damping materi- als have been developed with the reduction of vibration energy in the vehicle body in mind. Product Range SikaDamp ® solutions comprise a broad family of sound damping products based on elas- tomers, bitumen or butyl, which can also be coupled with a constraining layer. They are de- signed for excellent weight-to-performance ratios, while still providing industry-leading damping performance. The full range of solu- tions allows effective structure-borne noise reduction of car body elements and improved targeted acoustics without compromising weight. Meeting emission goals The newest “Ultralight” technology was cre- ated with the goal of helping OEMs design lighter, more fuel-efficient cars without com- promising on acoustic performance. Through the usage of ultra-low density damping mate- rial combinedwith constraint layer technology, we’ve been able to achieve an areal weight of 1.1 kg/m 2 compared to 5 kg/m 2 for typical NVH products. This results in weight savings of up to 80%. A midsize sedan has about 2 m 2 of damping material, so the average weight sav- ing potential is around 7 kg per vehicle making for a more fuel-efficient car. Performance Along with this extraordinary weight perfor- mance, the SikaDamp ® Ultralight comes with an exceptionally high damping performance that is comparable with traditional Alu-Butyl constrained layer systems. In combination with an alternative top layer, the material is also suitable for paint shop application on corrugated surfaces at a still above-average weight and damping performance. Process convenience Not only does this product perform well, it’s also very convenient to implement in a pro- duction line as it does not require any updated processes on the customer side. The appli- cation process is as easy as for other NVH products. Sika Automotive  https://qrco.de/bbT9rx 2018 Enlighten AwardWinner  https://qrco.de/bbT3Qt Websites Image: © Sika Automotive SikaDamp ® Ultralight on a lightweight carbon component S H A R E