The influence of the sharp transients introduced by the force window when applied to signals with DC components

摘要

For validation and updating of Finite Element Models their accuracy is measured in relation to experimental data (Experimental Modal Analysis vs. Computational Modal Analysis). A very fast method of obtaining the Modal Parameters used for validating the Computational Modal Analysis results involves instrumented hammer excitation of the structures. The frequencies and mode shapes can be obtained very accurately and the two results can be used for improving the finite elements model. If the force and excitation signals have very large DC components the use of the force window may raise some problems, such as the variation of modal parameters. This article will investigate the effects of such problems on the estimated modal parameters of a simple structure.