| One of the techniques used to enhance the damping characteristics of constrained damping treatments utilizes a spacer layer, called a "stand-off" layer, which is sandwiched between the viscoelastic layer and the base structure. This "stand-off" layer acts as a strain magnifier that magnifies the shear strain in the viscoelastic layer by virtue of increasing the distance between the viscoelastic layer and the neutral axis of the base structure. The "stand-off" layer must have high shear stiffness and must not significantly affect the bending stiffness of the composite structure in order to achieve high damping characteristics. Slotted "stand-off" layers are used to achieve such high shear stiffness and low bending stiffness. In these slotted "stand-off" layer, the geometry of the slots play a very important role in determining the effectiveness of the damping treatment. It is therefore the purpose of this dissertation to model the dynamics and damping characteristics of Passive Stand-off damping treatments using distributed-parameter approach as well as the finite element method. The predictions of the developed models are validated against the predictions of commercially available finite element software (ANSYS) and against experimental results. Close agreements are found between the predictions of the developed models, ANSYS models, and the experimental results.; The developed models present accordingly a valuable means for designing effective and optimal passive stand-off damping treatments for beams. The models can be easily extended to passive stand-off damping treatments for more complex structures such as plates and shells. |
