ESI will speak at the 6th International Styrian Noise, Vibration and Harshness Congress in Graz, Austria

ISNVH-2010 will focus on highly up-to-date topics for car manufacturers, suppliers and customers currently experiencing a tense economic situation. NVH engineers today are facing the challenge of designing lightweight vehicles with acceptable noise and vibration characteristics. In the context of the growing importance of hybrid and electric vehicles, car manufacturers require advanced experimental and simulation applications to evaluate and minimize the resulting NVH early in the design process to benefit from novel materials and arrangements.

ESI will contribute to the congress theme – Sustainable NVH solutions inspired by ecology and economy – by giving a talk on ‘The Effect of Beading on Radiated Noise’. The paper will be presented by Denis Blanchet, ESI’s Vibro-Acoustics Engineering Services Manager, on June 10 at 2:15 pm during the ‘Light Weight Design Contra NVH’ session (2).

In the automotive industry there is widespread use of beading to stiffen floor and dash panels.  The aim is to reduce vibration levels and simultaneously to reduce radiated noise. While beading has a positive effect close to the first panel mode’s natural frequency, it can also have a negative effect at all other frequencies. For the sake of simplicity, or because of lack of available implemented formulation in their simulation tools, engineers typically assume a radiation efficiency of “1” (one) over the whole frequency range.  This assumption leads to reducing the vibration levels only and can be misleading because the radiation efficiency tends to “1” (one) above coincident frequency but not below it. While increasing stiffness reduces vibration levels, it also increases radiation efficiency and can result in higher levels of radiated noise.

The presentation will compare vehicle panels with uniform cross-section and beaded panels in two different configurations:

• Academic frame and plate case
• Automotive floor

Mr. Blanchet will present vibration levels, radiation efficiency and sound radiated power for all cases.  He will also compare different beading types and draw conclusions as to whether these beadings actually reduce radiated noise or not.

We invite delegates to find out more about ESI’s Noise, Vibration and Harshness and Vibro-Acoustic solutions by visiting ESI’s booth in the exhibition area.