scholarly journals Nonlinear Dynamic Response of Nano-composite Sandwich Annular Spherical Shells

Author(s):  
Nguyen Dinh Duc ◽  
Vu Thi Thuy Anh ◽  
Vu Thi Huong ◽  
Vu Dinh Quang ◽  
Pham Dinh Nguyen

Abstract: In this research, the nonlinear dynamic response of functionally graded carbon nanotube reinforced composite (FG-CNTRC) sandwich annular spherical shells supported by Pasternak’ foundation is considered by using the analytical approach. Unlike existing works, the structure has three layers: FG-CNTRC layer – homogeneous core – FG-CNTRC layer. Several examples are considered to analyse the behaviour of this sandwich-structured composite. The classical shell theory (CST) is used to derive theoretical formulation delineating nonlinear dynamic response of FG-CNTRC sandwich annular spherical shells. The numerical results explain the effect of material, geometrical parameters, and elastic foundations on the nonlinear dynamic response of the annular spherical shell.  

Author(s):  
Zhicheng Yang ◽  
Meifung Tam ◽  
Yingyan Zhang ◽  
Sritawat Kitipornchai ◽  
Jiangen Lv ◽  
...  

This paper presents a numerical investigation on the nonlinear dynamic response of multilayer functionally graded graphene platelets reinforced composite (FG-GPLRC) beam with open edge cracks in thermal environment. It is assumed that graphene platelets (GPLs) in each GPLRC layer are uniformly distributed and randomly oriented with its concentration varying layer-wise along the thickness direction. The effective material properties of each GPLRC layer are predicted by Halpin-Tsai micromechanics-based model. Finite element method is employed to calculate the dynamic response of the cracked FG-GPLRC beam. It is found that the maximum dynamic deformation of the cracked FG-GPLRC beam under dynamic loading is quite sensitive to the crack location and grows with an increase in the crack depth ratio (CDR) and temperature rise. The influences of GPL distribution, concentration, geometry as well as the boundary conditions on the dynamic response characteristics of cracked FG-X-GPLRC beams are also investigated comprehensively.


Author(s):  
Pham Hong Cong ◽  
Phi Kien Quyet ◽  
Nguyen Dinh Duc

In this paper, the effects of lattice stiffeners and blast load on nonlinear dynamic response and vibration of auxetic sandwich honeycomb plates on Pasternak elastic foundations are considered. The remarkable point of this study is that the outer surfaces of the system reinforced by lattice stiffeners (including orthogonal stiffeners and oblique stiffeners) are made of functionally graded materials. Based on the analytical solution, the Reddy’s FSDT, the Airy’s stress functions, the Galerkin and the fourth-order Runge-Kutta methods, fundamental frequency, dynamic response and frequency–amplitude curves of the plates reinforced by lattice stiffeners under blast and mechanical loads are determined. Then, the result analyses the effect of lattice stiffeners, blast and mechanical loads, elastic foundations on nonlinear dynamic response and vibration of auxetic honeycomb plates. The optimal angle of oblique stiffeners which maximizes natural frequency and contemporaneously minimizes amplitude when changing geometrical parameters of auxetic honeycomb is also determined.


2016 ◽  
Vol 20 (3) ◽  
pp. 351-378 ◽  
Author(s):  
Dinh Duc Nguyen

In this paper, we study the nonlinear dynamic response of higher order shear deformable sandwich functionally graded circular cylindrical shells with outer surface-bonded piezoelectric actuator on elastic foundations subjected to thermo-electro-mechanical and damping loads. The sigmoid functionally graded material shells are made of the metal–ceramic–metal layers with temperature-dependent material properties. The governing equations are established based on Reddy’s third-order shear deformation theory using the stress function, the Galerkin method and the fourth-order Runge–Kutta method. Numerical results are given to demonstrate the influence of geometrical parameters, material properties, imperfection, elastic foundations, and thermo-electro-mechanical and damping loads on the nonlinear dynamic response of the shells. Accuracy of the present formulation is shown by comparing the results of numerical examples with the ones available in literature.


2017 ◽  
Vol 21 (8) ◽  
pp. 2816-2845 ◽  
Author(s):  
Nguyen D Duc ◽  
Ngo Duc Tuan ◽  
Phuong Tran ◽  
Tran Q Quan ◽  
Nguyen Van Thanh

This study follows an analytical approach to investigate the nonlinear dynamic response and vibration of eccentrically stiffened sandwich functionally graded material (FGM) cylindrical panels with metal–ceramic layers on elastic foundations in thermal environments. It is assumed that the FGM cylindrical panel is reinforced by the eccentrically longitudinal and transversal stiffeners and subjected to mechanical and thermal loads. The material properties are assumed to be temperature dependent and graded in the thickness direction according to a simple power law distribution. Based on the Reddy’s third-order shear deformation shell theory, the motion and compatibility equations are derived taking into account geometrical nonlinearity and Pasternak-type elastic foundations. The outstanding feature of this study is that both FGM cylindrical panel and stiffeners are assumed to be deformed in the presence of temperature. Explicit relation of deflection–time curves and frequencies of FGM cylindrical panel are determined by applying stress function, Galerkin method and fourth-order Runge-Kutta method. The influences of material and geometrical parameters, elastic foundations and stiffeners on the nonlinear dynamic and vibration of the sandwich FGM panels are discussed in detail. The obtained results are validated by comparing with other results in the literature.


2018 ◽  
Vol 22 (3) ◽  
pp. 658-688 ◽  
Author(s):  
Nguyen Dinh Duc ◽  
Ngo Duc Tuan ◽  
Pham Hong Cong ◽  
Ngo Dinh Dat ◽  
Nguyen Dinh Khoa

Based on the first order shear deformation shell theory, this paper presents an analysis of the nonlinear dynamic response and vibration of imperfect eccentrically stiffened functionally graded material (ES-FGM) cylindrical panels subjected to mechanical, thermal, and blast loads resting on elastic foundations. The material properties are assumed to be temperature-dependent and graded in the thickness direction according to simple power-law distribution in terms of the volume fractions of the constituents. Both functionally graded material cylindrical panels and stiffeners having temperature-dependent properties are deformed under temperature, simultaneously. Numerical results for the dynamic response of the imperfect ES-FGM cylindrical panels with two cases of boundary conditions are obtained by the Galerkin method and fourth-order Runge–Kutta method. The results show the effects of geometrical parameters, material properties, imperfections, mechanical and blast loads, temperature, elastic foundations and boundary conditions on the nonlinear dynamic response of the imperfect ES-FGM cylindrical panels. The obtained numerical results are validated by comparing with other results reported in the open literature.


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