Modal analysis of a beam with radiation damping: Numerical and experimental results

In large structures, the excitation energy produced by an impact force may not be sufficient to spread throughout the structure and excite global modes. Thus, one may be interested in the dynamic characterization of the excited part of the structure by taking into consideration the wave propagation through its boundaries. This radiation damping is a source of local damping and, as a consequence, causes modal complexity. The spectral element method is adopted here to describe the modal characteristics of a system with radiation damping. A semi-infinite Euler-Bernoulli beam, whose span is interrupted by a spring with translational and rotational stiffness, is used as an example to illustrate the main features of the phenomenon characterized by modal complexity and to obtain a simple but meaningful experimental confirmation. This method could be useful in the modal characterization of a part of a structure. ©2007 SAGE Publications.