Browse Publications Technical Papers 2007-01-2385
2007-05-15

A New Method for Obtaining FRF of a Structure in Area Where Impact Hammer Cannot Reach 2007-01-2385

The Frequency Response Function (FRF) is a fundamental component to identifying the dynamic characteristics of a system. FRF's have a significant impact on modal analysis and root cause analysis of NVH issues. In most cases the FRF can be easily measured, but there are instances when the measurement is unobtainable due to spatial constraints. This paper outlines a simple experimental method for obtaining a high quality input-output FRF of a structure in areas where an impact hammer can not reach during impact testing. Traditionally, the FRF in such an area is obtained by using a load cell extender with a hammer impact excitation. A common problem with this device is a double hit, that yields unacceptable results. The new method provided in this paper is shown to be superior to the traditional method for several reasons: (i) it is simple and requires no new equipment, (ii) a double hit issue is avoided, (iii) the desired FRF is calculated using a closed form equation, provided in this paper, which results in a more accurate solution.

SAE MOBILUS

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

Access SAE MOBILUS »

Members save up to 18% 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

A Study of NVH Vehicle Testing Variability

2005-01-2553

View Details

TECHNICAL PAPER

Tyre/Road Noise: Dominant Mechanism, Prediction And Potential For Improvement

2004-28-0058

View Details

TECHNICAL PAPER

Correlation of Axle Build Parameters to End-of-Line NVH Test Performance Part I: Preparing the Data for Multivariate Regression Analysis

2012-01-0727

View Details

X