Dynamics Analysis Of Passive Constrained Layer Damping Structure By The Distributed Parameter Transfer Function Menthod

Passive constrained layer damping (PCLD) is broadly used in aerospace structures for vibration control, which has many advantages such as wide control frequency, high reliability, good robustness, simple structural form and low cost. The emphasis of this dissertation is to establish a methodological system for PCLD structure dynamic analysis with distributed parameter transfer function method (shortened as transfer function method), and to solve a series of special subject problems based on the methodological system such as dynamic optimization of PCLD structure, parameter random analysis and model updating of viscoelastic material. The main achievements are summarized as follows:For dynamic problems of the beam with full and partial PCLD treatment, the transfer function method is proposed. The motion differential equations and boundary conditions are derived for PCLD beam by the Hamilton principle. The system equation in state space is then established, and the closed-form solutions are obtained by the transfer function method.For dynamic problems of the PCLD plate, the transfer function method is proposed. The motion equations and boundary conditions are deduced for the plate with full PCLD treatment, and the analytical solutions of the plate with two opposite simply-supported edges are presented through trigonometric series expansion. In order to adapt to arbitrary boundary conditions, the PCLD plate is divided into several strip elements in breadth, and the element stiffness matrix and element mass matrix are deduced. Then, the semi-analytical solutions of the plate with full and partial PCLD treatment are obtainedFor dynamic problems of the PCLD cylindrical shell, the transfer function method is proposed. Based on Donnell assumptions, the motion equations and boundary conditions are derived for the cylindrical shell with full PCLD treatment, and the equations are solved by the transfer function method. Furthermore, the dynamic problem of the cylindrical shell with partial ring-shape PCLD treatment is analyzed.Optimization models of single-objective and multi-objective are established for PCLD design parameters. In single-objective optimization, the aim is to maximize each mode loss factor. In multi-objective optimization, the aims are to maximize each mode loss factor, to minimize each frequency's shift and to minimize the PCLD mass. The PCLD start placement, PCLD length, constrained layer thickness and viscoelastic layer thickness are chosen as design variables.The influences of parameter randomness in viscoelastic material model are researched on dynamic characteristics of PCLD structure. The model parameters are updated. This dissertation has important value on both theory and practical application, which extends the applied range of the transfer function method and provides a theoretical basis for the use and design of PCLD structure in aerospace industrial fields.