Development of a novel surface damping treatment

Eyyüpoğlu, Kemal Okan
Constrained layer surface damping treatments techniques have been widely used in commercial and defense products to increase the damping performance. It is known that the performance of surface damping treatments highly depend on the strain energy in the viscoelastic layer. As the strain energy in the viscoelastic layer increases, the energy dissipation magnifies which results in higher damping performance. A good way to magnify strain energy in viscoelastic layer is to increase the distance between the viscoelastic layer and the neutral axis of the base beam. This can be achieved by using stand-off layer which is a layer between the viscoelastic layer and the base beam. The stand-off layer should have very low bending stiffness in order not to prevent the deformation of the beam in lateral direction. Also stand-off layer should have very high shear stiffness in order to allow the viscoelastic layer to take all the shear strain energy on itself. The requirement of having a low bending stiffness and high shear stiffness in addition to minimizing the mass of the damping treatment while targeting a certain damping performance may be translated into a shape optimization problem for the design of the stand-off layer. In this dissertation, a parametric finite element model of the stand-off constrained damping treatment is developed by using a commercial product (ANSYS) and the geometry of the stand-off layer are optimized by using another commercial product (MATLAB). For the determination of the optimum shape of the stand-off layer, topology optimization approach is used along with genetic optimization technique. In the optimization studies conducted in the thesis, the optimum stand-off layer geometry with minimum weight that does not compromise damping performance is seeked.