Modal Analysis of the Passive Constrained Layer Beams Based on Spectrally Formulated Exact Normal Modes

초록

Modal analysis method (MAM) is introduced for the fully coupled structural dynamic problems. In this pa-per, the beam with passive constrained layered damp-ing (PCLD) treatments is considered as a representa-tive problem. The beam consists of a viscoelastic layer that is sandwiched between the base structure and an constrained layer. The exact natural modes are spectrally formulated form a set of fully coupled dy-namic equations of motion of a PCLD beam. The or-thogonality property of the exact natural modes is then derived in a closed form to complete the modal analysis method. The accuracy of the present MAM is evaluated through some numerical examples: the dy-namic characteristics obtained by the present MAM are compared with the results by spectral element method (SEM) and finite element method (FEM). It is shown that MAM solutions converge to the accurate SEM solutions as the number of exact natural modes used in MAM is increased.