0
Research Papers

Positioning of Deadeners for Vibration Reduction in Vehicle Roof Using Embedded Sensitivity

[+] Author and Article Information
Danilo Bruneli Reis

 Ford Motor Co., Brazil, Tatuí Proving Ground, VED-NVH Engineering, Rodovia SP127, km 124, 18277-670 Tatuí, SP, Brazildreis10@ford.com

Rodrigo Nicoletti1

Department of Mechanical Engineering, Engineering School of São Carlos, University of São Paulo, Av. Trabalhador São-Carlense, 400, 13566-590 São Carlos, SP, Brazilrnicolet@sc.usp.br

1

Corresponding author.

J. Vib. Acoust 132(2), 021007 (Mar 17, 2010) (8 pages) doi:10.1115/1.4000769 History: Received October 17, 2008; Revised May 22, 2009; Published March 17, 2010; Online March 17, 2010

The noise, vibration and harshness (NVH) performance of passenger vehicles strongly depends on the fluid-structure interaction between the air in the vehicle cavity and the sheet metal structure of the vehicle. Most of the noise and vibration problems related to this interaction come from resonance peaks of the sheet metal, which are excited by external forces (road, engine, and wind). A reduction in these resonance peaks can be achieved by applying bitumen damping layers, also called deadeners, in the sheet metal. The problem is where these deadeners shall be fixed, which is usually done in a trial-and-error basis. In this work, one proposes the use of embedded sensitivity to locate the deadeners in the sheet metal of the vehicle, more specifically in the vehicle roof. Experimental frequency response functions (FRFs) of the roof are obtained and the data are processed by adopting the embedded sensitivity method, thus obtaining the sensitivity of the resonance peaks on the local increase in damping due to the deadeners. As a result, by examining the sensitivity functions, one can find the optimum location of the deadeners that maximize their effect in reducing the resonance peaks of interest. After locating the deadeners in the optimum positions, it was possible to verify a strong reduction in resonance peaks of the vehicle roof, thus showing the efficiency of the procedure. The main advantage of this procedure is that it only requires FRF measurements of the vehicle in its original state not needing any previous modification of the vehicle structure to find the sensitivity functions.

Copyright © 2010 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 9

Sensitivity of H71 as a function of local damping among measuring points in the frequency range of interest (70–80 Hz)

Grahic Jump Location
Figure 10

Sensitivity of H91 as a function of local damping among measuring points in the frequency range of interest (70–80 Hz)

Grahic Jump Location
Figure 17

Regions of the roof where critical FRFs have highest sensitivity to local damping change

Grahic Jump Location
Figure 18

Deadeners mounted on the vehicle roof

Grahic Jump Location
Figure 19

FRFs of the vehicle roof with deadeners in the regions defined in the sensitivity analysis (10–25 Hz)

Grahic Jump Location
Figure 20

Critical FRFs after mounting the deadeners on vehicle roof (70–80 Hz)

Grahic Jump Location
Figure 21

Embedded sensitivity functions of all FRFs of the original system to local damping in the areas of the roof defined in the sensitivity analysis: (a) |dHjk/dC12|, (b) |dHjk/dC23|, (c) |dHjk/dC14|, and (d) |dHjk/dC36|

Grahic Jump Location
Figure 1

Analytical model of a two degree-of-freedom mechanical system

Grahic Jump Location
Figure 2

Mesh of measuring points in the vehicle roof: (a) measuring points and (b) vehicle roof with accelerometers

Grahic Jump Location
Figure 4

FRFs of the vehicle roof without deadeners (10–125 Hz)

Grahic Jump Location
Figure 5

FRFs with highest peak amplitudes in the frequency range of interest (70–80 Hz)

Grahic Jump Location
Figure 6

Possible regions subjected to local damping change among the measuring points

Grahic Jump Location
Figure 7

Sensitivity of H11 as a function of local damping among measuring points in the frequency range of interest (70–80 Hz)

Grahic Jump Location
Figure 8

Sensitivity of H33 as a function of local damping among measuring points in the frequency range of interest (70–80 Hz)

Grahic Jump Location
Figure 3

Vehicle body supported by pneumatic benches

Grahic Jump Location
Figure 16

Sensitivity of H79 as a function of local damping among measuring points in the frequency range of interest (70–80 Hz)

Grahic Jump Location
Figure 11

Sensitivity of H13 as a function of local damping among measuring points in the frequency range of interest (70–80 Hz)

Grahic Jump Location
Figure 12

Sensitivity of H93 as a function of local damping among measuring points in the frequency range of interest (70–80 Hz)

Grahic Jump Location
Figure 13

Sensitivity of H73 as a function of local damping among measuring points in the frequency range of interest (70– 80 Hz)

Grahic Jump Location
Figure 14

Sensitivity of H77 as a function of local damping among measuring points in the frequency range of interest (70–80 Hz)

Grahic Jump Location
Figure 15

Sensitivity of H99 as a function of local damping among measuring points in the frequency range of interest (70–80 Hz)

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In