ANSYS and analytical modeling of elastic-viscoelastic-elastic sandwich beams.

摘要

Modal testing of a high-technology component is usually very expensive to perform; therefore, major portion of a design work is carried out with simulation software. Finite Element Analysis techniques, nowadays, can efficiently represent viscoelastic damping.;A set of elastic-viscoelastic-elastic sandwich beams are modeled in ANSYS. Beams are having varying thickness and some are partial-patch damped and others are full-patch damped. Modal analysis in ANSYS has been done for all beams and the natural frequencies are studied. A comparative study has also been done with Sisemore's experimental results [1] and with Mead-Markus results [2] in order to study the effect of change in boundary conditions between the two models. The Modal Strain Energy (MSE) method is used to obtain the damping loss factor in the sandwich beams. Harmonic Analysis in ANSYS on all beams is also done. Harmonic Analysis plots are used to illustrate the effect of boundary condition differences between Sisemore's experimental, partial-patch beams, and Mead-Markus full-patch beams.;Analytical approaches to a simple cantilever beam, a full-patch viscoelastic sandwich beam, and a partial-patch viscoelastic sandwich beam have been done. The thesis illustrated the major difference in approach to the shear strain in viscoelastic core layer of the sandwich beam taken by Sisemore's and Mead-Markus analytical models. It also points out the correction made in Mead-Markus's beam boundary conditions by Sisemore and effects on natural frequency and damping of the beams.