Dissipative properties of three-layered composite structures. 3. Objects of study

Abstract

Object and purpose of research. The object of research is a sandwich plate formed by two rigid anisotropic layers and a soft isotropic layer of viscoelastic polymer in the middle. Each rigid layer is an anisotropic structure formed by a finite number of arbitrary oriented orthotropic viscoelastic layers of composites. The purpose of work is to choose the objects of research demonstrating main features of parameters of natural decaying oscillation of sandwich plates. Materials and methods. Qualitative analysis of differential equations describing decaying oscillations of anisotropic plates of various compositions and reinforcement structures. Main results. The main objects of research are two special reinforcement structures of rigid layers made up of unidirectional CFRP layers: symmetric and asymmetric structures. The symmetric reinforcement structure of rigid layers is formed by an assembly of unidirectional CFRP layers with the same orientation relative to the global axes of these layers. In the asymmetric structures the unidirectional CFRP layers are oriented in the opposite directions with respect to the global axes of the rigid layers. Results of numerical modeling of quasi-homogeneous monocline plate dynamic response are given. It is shown that coupled oscillations of the symmetric sandwich plate are described by two systems of differential equations similar to the equation systems that describe decaying oscillations of quasi-homogeneous monocline plate. While the coupled oscillations of the asymmetric sandwich plate are described by two systems of differential equations coinciding with the systems of differential equations describing decaying oscillations of globally orthotropic sandwich plate. Conclusion. Further to this paper, discussion of numerical experiments on chosen objects of research will be given.