Experimental Parameter Identification of Structural Components. The Method Using the Base Excitation Test.

An experimental identification method for qualifying analytical models of a structural dynamic is proposed. The method can be applied, at the design stage, when assembling a set of sub-structures. Its major feature is to represent correctly the equilibrium of forces within each substructure. The characteristic representation of a substructure obtained from the experiment consists of a set of eigenfrequencies, the corresponding modal damping coefficients and some boundary factors. These characteristics are determined by measuring the excitation forces, and the mathematical algorithm employed guarantees that the measured forces will be conserved in the analytical representation of the substructure. Only a few data points, which can be obtained from dynamic tests with sinusoidal base excitation, are required. Two example problems have been analyzed by means of a finite-element package and also tested experimentally, it is shown that these two sample problems yield consistent results.