Case Study: An Automobile Body

This chapter considers the application of correlation and validation techniques to an automobile body, commonly called a body-in-white. The automobile was a 1991 GM Saturn four door Sedan (Brughmans et al., 1992). The finite element model of this car had 46830 degrees of freedom (half model). A multi-point experimental modal analysis (EMA) survey was performed with 360 response degrees of freedom. Classical techniques for correlation analysis such as the Modal Assurance Criterion (MAC, Chapter 4) were applied. Error localisation methods identified the regions of the finite element model that caused most of the discrepancies between the model and the measurements. The Bayesian, or minimum variance, updating method (Chapter 8) reduced the difference between the finite element model and measured modal model to acceptable limits.