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Free vibration and buckling analysis of composite laminated shells using the refined zigzag theory

Zhang Haibo, Gao Yihang, He Dan, Yang Wanli

Journal of Theoretical and Applied Mechanics

2022

Vol. 60 nr 3

435--448

In this study, a new composite laminated shell model is proposed for free vibration and stability analysis based on the refined zigzag theory (RZT). In contrast to the published shell models based on the first-order shear deformation theory (FSDT), piecewise-linear zigzag functions are utilized to provide a more realistic representation of deformation states of a transverse shear-flexible shell. In the present formulation, the governing equations and boundary conditions of composite laminated shells are established by d’Alembert’s principle to obtain natural frequencies and critical buckling loadings. In order to evaluate the effectiveness and performance of the present new model for composite laminated shells, examples of free vibration and buckling analysis are carried out for cylindrical and spherical shells involving different lamination schemes and design parameters. The results are compared with the three dimensional (3D) exact, first-order and some high-order solutions in the literature. Numerical results show that the present model not only has high accuracy but also has superior computational efficiency in comparison with high-order models, such that it may show a great potential in engineering applications.

Study of Molecular Perovskite (H2dabco)[NH4(ClO4)3]/Carbon Nanotubes Energetic Composite

Hu Li-shuang, Liu Yang, He Dan, Yang Yajun, Gong Shida, Guang Chunyu, Deng Peng, Hu Shuangqi

Central European Journal of Energetic Materials

2022

Vol. 19, no. 1

91--105

An ammonium perchlorate (AP, NH4(ClO4)3)-based molecular perovskite energetic material (H2dabco)[NH4(ClO4)3]/carbon nanotubes (DAP/CNTs) composite was prepared and characterized. Molecular perovskite DAP samples were synthesized by a facile one-pot reaction of triethylenediamine, perchloric acid (PCA, HClO4), and AP via a molecular assembly strategy. The results showed that the mechanical sensitivity (impact and friction sensitivities: >120 cm and 20%) and electrostatic spark sensitivity (8.90 J) of the DAP/CNTs energetic composite with 10 wt.% CNTs exhibited less sensitivity than that of DAP (impact, friction and electrostatic spark sensitivities: 112.3 cm, 45%, and 5.39 J, respectively), because of the mixing desensitization mechanism of CNTs. Compared with the pure DAP, the DAP/CNTs energetic composite has better performance with respect to thermal stability, exothermic capacity, and excellent continuous combustion properties. The DAP/CNTs energetic composite has potential application in a weapons system.