AUTOMATIC CHOICE OF MEASUREMENT LOCATIONS FOR DYNAMIC TESTING

This paper examines the problem of choosing an optimum, or near-optimum, set of measurement locations for experimental modal testing and suggests criteria whereby the suitability of the chosen locations can be assessed. Two methods of coordinate selection are used: one based on Guyan reduction and the other on the Fisher information matrix. Each begins with a detailed finite element model of the structure being tested. Both procedures reduce this model by one degree of freedom at a time until the number of degrees of freedom in the reduced model equals the number of measurement locations required. The choice of the eliminated coordinates is generally automatic, and the coordinates of the reduced model are those used for modal testing. Five possible methods for assessing the suitability of the chosen measurement locations are considered, and examples are given of the application of these methods to simple structures.