چكيده به لاتين
In this thesis, the buckling and free vibration analyses of two joined laminated conical shells are investigated based on theoretical, numerical and experimental views. Governing equations have been derived using Hamilton’s Principle and First order Shear Deformation Theorem (FSDT). The analytical solutions are obtained in the form of Power Series based on Separation of Variables Method. The Boundary Conditions (BC) at both ends of the joined shells and the Continuity Conditions (CC), at the conical shells contact, are extracted from energy formulations. As a verification of result, according to other researches, the result of a single conical shell are compared with two joined conical shells with the same semi-vertex angles. As a comparing result, present theoretical results are extracted using Finite Element Method (FEM). Of course, the results are validated by experimental modal analysis and buckling test. For experimental modal analysis, four samples of joined glass/epoxy shells are prepared using manufacturing method presented in this thesis. Also, the experimental results are achieved using methods of frequency response measurement, data acquisition and modal parameters estimation. For experimental buckling test, four samples of joined cross-ply and four samples of angle-ply shells are prepared. Finally, experimental buckling test under axial compression is done using universal buckling test machine. Present results are validated with experimental results. The effects of semi vertex angles, circumferential modes, number of layers, thicknesses, lengths, composite material properties and fiber angles of shells on critical buckling load and natural frequencies are considered. The modal results show a maximum 19% differences between experimental and theoretical results. On the other hand, there are a maximum 11.77% differences between experimental and theoretical critical buckling loads. Also, the experimental and FEM results of buckling analysis illustrate a maximum 9.33% differences
