Complex-valued Modal Loss Factor Maximization for an Unconstrained Damping Layout with Topology Optimization

Abstract

An unconstrained viscoelastic damping treatment is an effective way to control vibration in structures. With a fully-covered damping treatment, the mass of structure is heavy and the damping effect is not significantly increasing. Thus, a well-distributed partial damping treatment is an effective method in terms of a less weight with high damping effects. To determine the placement of damping material, topology optimization technique is used. The objective function is the modal loss factor at a specific mode and the constraint is a fixed mass of viscoelastic damping material. In order to accurately estimate the modal loss factor, complex-valued eigenvalues are considered. The modal strain energy method has been found to over-predict the modal loss factors where the dissipative elements have a high material loss factor. This research shows that significant beneficial damping effects can be achieved by using topology optimization with high accuracy of modal loss factors.