Browse Publications Technical Papers 2007-01-2302
2007-05-15

Virtual SEA: Towards an Industrial Process 2007-01-2302

In the high frequency range, the SEA method has been applied to air borne path with success to predict both internal and external sound environment. Nevertheless, structure-borne prediction is still at issue -especially for cars, in the range 200 to 2000 Hz- as results are widely dependant on subsystem partition and validity of various assumptions required by SEA.
Experimental SEA test technique (ESEA), applied to car bodies, has brought to the fore that SEA power balanced equations could robustly describe structure-borne noise. To make ESEA predictive, the database of measured FRF is simply replaced and enlarged by synthesized data generated from a finite element (FE) model and a selected observation grid of nodes. This technique, called Virtual SEA (VSEA), has been presented at SAE/NVC 2003. Since then, many developments have been carried out to improve the general efficiency of the three main steps of VSEA:
  • The generation of the band-integrated FRF database (between nodes of the observation grid) is now integrated in the virtual SEA solver. As several millions of band averaged FRF can be required for a full car body analysis, a specific fast FRF synthesis is performed using analytical integration and band-optimized solutions by limiting the number of cross-modal terms in the series solution.
  • Automatic subsystem partition has been widely improved by developing different algorithms that limit the sensitivity of results to initial conditions.
  • ESEA loss matrix identification process has been reviewed for better resolution of highly non homogeneous system such as car bodies. The normalization of squared FRF matrix by the input mobility matrix allows a direct determination of subsystems modal density. The dynamics of a very large 3D FE model can thus be compressed into a small SEA loss matrix while preserving local transfer information at all nodal observation points.
Examples of applications are shown on car components.

SAE MOBILUS

Subscribers can view annotate, and download all of SAE's content. Learn More »

Access SAE MOBILUS »

Preview Document Add to Cart
Members save up to 16% off list price.
Login to see discount.
Special Offer: Download multiple Technical Papers each year? TechSelect is a cost-effective subscription option to select and download 12-100 full-text Technical Papers per year. Find more information here.
We also recommend:
TECHNICAL PAPER

Virtual SEA: Mid-Frequency Structure-Borne Noise Modeling Based on Finite Element Analysis

2003-01-1555

View Details

TECHNICAL PAPER

Influence of Low-Frequency Powertrain-Vibrations on Driveability-Assessments

2010-01-1419

View Details

TECHNICAL PAPER

Evaluation of Vehicle Systems Structural Durability Using PSD Based Fatigue Life Approach

2012-01-0953

View Details

X