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In this paper, the Haar wavelet discretization method (HWDM) is proposed for the calculation of natural frequency of the laminated composite conical-cylindrical coupled shells. The displacement components of the system are set by the first order shear deformation shell theory (FSDST), and all the displacement functions of conical and cylindrical shells including boundary conditions are obtained by the Haar wavelet and its integrals. The Hamilton’s principle is applied to the constitution equation and the artificial spring technique is introduced to generalize the boundary and continuity conditions of the coupled structure. The convergence and accuracy of the proposed method are validated by comparing with the results obtained from the previous works and finite element analysis, and the proposed method shows high accuracy, reliability and good convergence in both individual structure and coupled structure. Using the proposed method, in the laminated composite conical–cylindrical coupled shell with any boundary condition, new numerical results on the natural frequency are obtained along with the parameter studies, and these results can provide the referential data for the following research in this field.

In this paper, a progressive damage model reflecting the interaction between delamination and intralaminar crack is developed to predict fracture behaviors and the ultimate load-bearing ability of the fiber-reinforced polymer laminates subject to quasi-static load. Initiation and evolution of intralaminar crack in composites are modeled using a continuum damage mechanics model, which has the capability to reliably predict the discrete crack direction by introducing the crack direction parameter while analyzing the multi-failure of FRP composites. Delamination is modeled using a cohesive zone method with the mixed bilinear law. When the continuum damage model and cohesive zone model are used together, the interactive behavior between multiple failure mechanisms such as delamination induced by matrix cracking often seen in the failure of composite laminates is not generally captured. Interaction between delamination and intralaminar crack in FRP composite structures is investigated in detail and reflected in a finite element analysis in order to eliminate the drawbacks of using both models together. Good agreements between numerical results and experimental data are obtained.

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In this paper, the meshfree method is adopted for the first time to study the free vibration of a composite laminated double-plate system (CLDPS). The first order shear deformation theory is used to analyze the free vibration of the CLDPS, and the artificial elastic spring technique is utilized to generalize its boundary conditions. All of the displacement functions including the boundary conditions are approximated by a meshfree shape function. The reliability and accuracy of the proposed technique are verified through the comparison with the results in the previous literature and by the finite element method. The effects of various boundary conditions, material properties, and geometries of the CLDPS on its natural frequencies are considered in detail.