Research On Dynamical And Sound Transmission Characteristics Of Composite Laminated Plate With Delamination

To enhance the combat capabilities of modern naval ships, it has a certain significance of improving the acoustic stealth performance. Because of the excellent advantages, advanced composites represented by fiber reinforced composite material have been widely applied in ship and other fields. Different from metal materials, layer geometry and delamination may have influences on dynamic characteristics and acoustic properties of laminated plates. As a result, the research on dynamic and sound transmission characteristics of composite laminated plate is of great value.Based on first order shear theory, dynamic model of intact plate and delamination plate are established respectively. The displacements on the profile of the delamination edge satisfy continuous condition and linear spring virtual contact elements are adopted to simulate the mechanical behavior of sub-laminates in delamination area. The finite element analysis equations of laminate plate are derived, and finite element programs are written for dynamic analysis. The vibration responses and transfer functions are calculated by using forced vibration analysis method respectively. For intact plate and elliptic delamination plate which are embedded in an infinite plate, combined with the finite element method and Rayleigh integral on the plate surface, acoustic radiation model and sound transmission model are established respectively to analyze acoustic properties of laminated plate.For typical structures, stress distribution and effects of layer geometry, damping ratio and excitation frequency on dynamic responses are discussed. The influences of layer geometry on acoustic radiation of laminated plate excited by point force are considered. When a laminated plate is stimulated by plane waves or in diffuse sound field, the effects of incident angle, layer geometry on sound transmission characteristics are analyzed. At last, for a laminated plate with delamination, the effects of boundary condition, size and location of delamination on sound transmission are discussed in this paper. Characteristics of dynamic and sound transmission of laminated plate are revealed theoretically. What we have got from example analysis has practical value in engineering...