Analyses of nonlinear dynamics of imperfect nanocomposite circular cylindrical shells with swirling annular and internal fluid flow using higher order shear deformation shell theory

Aluminium Foam Sandwich (AFS) panels are a type of structural configuration in which two aluminium thin layers enclose a core made of foamed aluminium. Both the metallic characteristic of the matrix and the foam porosity lead to a remarkable combination of properties which range from high specific stiffness to thermal and acoustic isolation. However, these characteristics, depending on core properties as foam density, pores morphology, type and size of gas bubbles, are obtained by means of a manufacturing process that is not fully controlled. Thus, in order to reduce the financial and temporal costs of the campaign of experimental tests needed for completely understanding the properties and potentialities of AFS panels, similitude methods can be used so that scaled-down models can be tested in place of the full-scale structure. In this work, the similitude conditions and scaling laws of Alulight® AFS panels with two different boundary conditions (simply supported and free-free) are derived and validated. In particular, two different sets of conditions are derived: the first by expliciting all the geometrical and material properties, the second by combining some parameters into just one with physical meaning, the bending stiffness. The analysis in similitude is addressed towards the prediction of vibroacoustic properties such as natural frequencies, Frequency Response Function (FRF) and radiated acoustic power. Both models in complete and partial similitude are investigated. While the former allow to reconstruct the vibroacoustic characteristics of the prototype, the latter does not. Furthermore, it is proved that it is possible to derive a simplified set of similitude conditions if many parameters are gathered into just one parameter with physical meaning.

Section: Introductionmentioning

confidence: 99%

The vibroacoustic behaviour of aluminium foam sandwich panels in similitude

Casaburo

Petrone

Meruane

et al. 2021

“…Kolahchi et al [28][29][30][31][32] presented the dynamic buckling analysis of nano/microplate with many models. Some authors also investigated nanocomposite structures with different approaches [33][34][35][36][37][38]. Besides, the buckling and vibration of FG-GPLRC composite structures have attracted significant the attention of researchers.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear dynamics of functionally graded graphene nanoplatelet reinforced polymer doubly-curved shallow shells resting on elastic foundation using a micromechanical model

Hoang

Tien

Ninh

et al. 2020

Self Cite

The paper focuses on the nonlinear vibration of functionally graded graphene nanoplatelet reinforced composite doubly curved shallow shells resting on elastic foundations. The graphene nanoplatelet reinforced composites are assumed to be distributed uniformly and functionally graded through the thickness. The material properties are assumed to be temperature-dependent and are estimated through the Halpin–Tsai micromechanical model, while the Poisson’s ratio, density mass, and thermal expansion are implemented by the rule of mixtures. The mathematical formulation is developed based on the classical shell theory and Von Karman-Donnell geometrical nonlinearity assumption. The dynamical responses of a simply supported functionally graded-graphene nanoplatelet reinforced composite doubly curved shallow shells are obtained by employing the Airy’s stress function and the Galerkin’s method. The responses of nonlinear vibration as time history, frequency-amplitude curve, phase plane graphs, and Poincare maps are carried out in this paper. In addition, the effects of the environment, graphene nanoplatelets weight fraction, graphene nanoplatelets distribution patterns, and thickness-to-length ratio are scrutinized. The obtained results are also compared and validated with those of other studies.

“…Liew et al considered dynamic responses of CNTs reinforced nanocomposite cylinders under impact loading with the high-order shear deformation theory [17]. Ninh [18][19][20][21] investigated the vibration and nonlinear torsional buckling of nanocomposite shells with piezoelectric actuators considering the electro-thermo-mechanical coupling, and the imperfect nanocomposite circular cylindrical shells conveying to internal and external fluid flow were analyzed by them for nonlinear dynamic behaviors. Besides, GPLs reinforced nanocomposites have also been focused on by many scholars.…”

Section: Introductionmentioning

confidence: 99%

Guided waves propagation in sandwich cylindrical structures with functionally graded graphene-epoxy core and piezoelectric surface layers

Han

2020

As an ideal reinforcing nanofiller, graphene platelets (GPLs) can significantly improve physical properties of nanocomposites, which have attracted considerable attention for design and development of advanced lightweight nanocomposite structures in engineering. In this paper, a sandwich cylindrical structure is considered for dispersion properties of wave propagation by axisymmetric isogeometric analysis (IGA). The sandwich structure is composed of a functionally graded (FG) nanocomposite core and piezoelectric surface layers. Graphene platelets are dispersed in the interlayer by three typical distribution patterns through the thickness. In virtue of the symmetry and the advantages of isogeometric analysis, the sandwich cylindrical structure can be described by one-dimensional representation along the radial direction. Based on Hamilton’s principle, parameterized governing equation for wave propagation is obtained with the non-uniform rational B-splines (NURBS), which leads to an second-order eigenvalue problem. The modified wave finite element (WFE) method and the Chebyshev spectral element (SE) method are utilized to verify the reliability and accuracy of this approach. Then, the effects of several significant parameters of GPLs and geometric sizes of the sandwich structure on wave propagation characteristics are discussed in details. The results of this study are beneficial to deeply understanding and control of wave propagation in advanced piezoelectric composites for the applications in structural health monitoring and nondestructive evaluation.