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Recent research advances on the dynamic analysis of composite shells: 2000-2009

Analysis of wave propagation characteristics in piezoelectric cylindrical composite shells reinforced with carbon nanotubes

Dynamics of wave propagation in carbon nanotube (CNT)-reinforced piezocomposite cylindrical shells affected by nanotube agglomeration is investigated in this study for the first time by developing an analytical approach incorporating existing theories and models. The Mori-Tanaka micromechanics model in combination of the first-order shear deformation shell theory and wave propagation solution are employed to determine wave propagation characteristics of piezocomposite cylindrical shells reinforced with agglomerated CNTs. The effects of both partial and complete nanotube agglomerations on the effective elastic properties and wave dynamics are examined within various axial and circumferential wave numbers for different wave modes by solving an eigenvalue problem. It is found that nanotube agglomeration leads to the reduction of wave phase velocity as a result of decrease in the effective elastic properties. The developed methodology in this study can be used for analysis of the data of structural health monitoring by the non-destructive testing (NDT) in estimating the degree of nanotube agglomeration in nanocomposites.

Effects of nanotube agglomeration on wave dynamics of carbon nanotube-reinforced piezocomposite cylindrical shells

Free vibration analysis is carried out for piezoelectric coupled carbon nanotube (CNT)-reinforced composite cylindrical shells with the influences of various boundary conditions and hygrothermal environmental conditions for the first time. A simple and effective non-iterative mathematical method is used to calculate the natural frequencies. The equilibrium equations of motion are obtained based on the first-order shear deformation shell theory with the coupling effects of piezoelectricity, temperature, and moisture, respectively based on the Maxwell equation, the Fourier heat conduction equation, and the Fickian moisture diffusion equation. The Mori-Tanaka micromechanics model is used to estimate the resulting material properties for a composite shell reinforced with CNTs. Presented methodology and attained results are validated with the existing results in the literature. The effects of the boundary conditions, lamination stacking sequence, volume fraction and orientation of CNTs, piezoelectricity, and geometry of the shell on the natural frequencies of the shell are investigated. A moderate effect of temperature/moisture variation on the natural frequencies is also observed. It is found that the influence of structural boundary conditions is more significant at higher CNT volume fractions and for thicker and shorter shells, and the piezoelectricity effect is more obvious at higher circumferential mode. The model and results presented in this study can be utilized to determine vibration characteristics of smart CNT-reinforced composites subjected to hygrothermal loading as well as mechanical loading.

Free vibration analysis of smart laminated carbon nanotube-reinforced composite cylindrical shells with various boundary conditions in hygrothermal environments

Polarization effects on wave propagation characteristics of piezoelectric coupled laminated fiber-reinforced composite cylindrical shells

The effects of transverse shear, rotary inertia and thermal loads on wave propagation in orthotropic laminated piezoelectric cylindrical shells are studied in this paper. A dynamic model of laminated piezoelectric cylindrical shell is derived based on Cooper-Naghdi shell theory. The wave characteristics curves are obtained by solving an eigenvalue problem. Besides discussing the dispersion curves for different wave modes, effects of layer numbers, the thickness of piezoelectric layers and thermal environment on the wave characteristics curves were also studied. This solution method is validated by the classical solution of an elastic shell, and may be used to investigate wave propagation in laminated piezoelectric cylindrical shells with various laminated materials, layer numbers and thickness, in thermal environment.

K. Dong

Papers

The Effect of Transverse Shear, Rotary Inertia on Wave Propagation in Laminated Piezoelectric Cylindrical Shells in Thermal Environment: