scholarly journals An Alternative Electro-Mechanical Finite Formulation for Functionally Graded Graphene-Reinforced Composite Beams with Macro-Fiber Composite Actuator

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7802
Author(s):  
Yu Fu ◽  
Xingzhong Tang ◽  
Qilin Jin ◽  
Zhen Wu

With its extraordinary physical properties, graphene is regarded as one of the most attractive reinforcements to enhance the mechanical characteristics of composite materials. However, the existing models in the literature might meet severe challenges in the interlaminar-stress prediction of thick, functionally graded, graphene-reinforced-composite (FG-GRC)-laminated beams that have been integrated with piezoelectric macro-fiber-composite (MFC) actuators under electro-mechanical loadings. If the transverse shear deformations cannot be accurately described, then the mechanical performance of the FG-GRC-laminated beams with MFC actuators will be significantly impacted by the electro-mechanical coupling effect and the sudden change of the material characteristics at the interfaces. Therefore, a new electro-mechanical coupled-beam model with only four independent displacement variables is proposed in this paper. Employing the Hu–Washizu (HW) variational principle, the precision of the transverse shear stresses in regard to the electro-mechanical coupling effect can be improved. Moreover, the second-order derivatives of the in-plane displacement parameters have been removed from the transverse-shear-stress components, which can greatly simplify the finite-element implementation. Thus, based on the proposed electro-mechanical coupled model, a simple C0-type finite-element formulation is developed for the interlaminar shear-stress analysis of thick FG-GRC-laminated beams with MFC actuators. The 3D elasticity solutions and the results obtained from other models are used to assess the performance of the proposed finite-element formulation. Additionally, comprehensive parametric studies are performed on the influences of the graphene volume fraction, distribution pattern, electro-mechanical loading, boundary conditions, lamination scheme and geometrical parameters of the beams on the deformations and stresses of the FG-GRC-laminated beams with MFC actuators.

2017 ◽  
Vol 29 (7) ◽  
pp. 1430-1455 ◽  
Author(s):  
Vinyas Mahesh ◽  
Piyush J Sagar ◽  
Subhaschandra Kattimani

In this article, the influence of full coupling between thermal, elastic, magnetic, and electric fields on the natural frequency of functionally graded magneto-electro-thermo-elastic plates has been investigated using finite element methods. The contribution of overall coupling effect as well as individual elastic, piezoelectric, piezomagnetic, and thermal phases toward the stiffness of magneto-electro-thermo-elastic plates is evaluated. A finite element formulation is derived using Hamilton’s principle and coupled constitutive equations of magneto-electro-thermo-elastic material. Based on the first-order shear deformation theory, kinematics relations are established and the corresponding finite element model is developed. Furthermore, the static studies of magneto-electro-elastic plate have been carried out by reducing the fully coupled finite element formulation to partially coupled state. Particular attention has been paid to investigate the influence of thermal fields, electric fields, and magnetic fields on the behavior of magneto-electro-elastic plate. In addition, the effect of pyrocoupling on the magneto-electro-elastic plate has also been studied. Furthermore, the effect of geometrical parameters such as aspect ratio, length-to-thickness ratio, stacking sequence, and boundary conditions is studied in detail. The investigation may contribute significantly in enhancing the performance and applicability of functionally graded magneto-electro-thermo-elastic structures in the field of sensors and actuators.


Author(s):  
Mohamed-Ouejdi Belarbi ◽  
Abdelhak Khechai ◽  
Aicha Bessaim ◽  
Mohammed-Sid-Ahmed Houari ◽  
Aman Garg ◽  
...  

In this paper, the bending behavior of functionally graded single-layered, symmetric and non-symmetric sandwich beams is investigated according to a new higher order shear deformation theory. Based on this theory, a novel parabolic shear deformation function is developed and applied to investigate the bending response of sandwich beams with homogeneous hardcore and softcore. The present theory provides an accurate parabolic distribution of transverse shear stress across the thickness and satisfies the zero traction boundary conditions on the top and bottom surfaces of the functionally graded sandwich beam without using any shear correction factors. The governing equations derived herein are solved by employing the finite element method using a two-node beam element, developed for this purpose. The material properties of functionally graded sandwich beams are graded through the thickness according to the power-law distribution. The predictive capability of the proposed finite element model is demonstrated through illustrative examples. Four types of beam support, i.e. simply-simply, clamped-free, clamped–clamped, and clamped-simply, are used to study how the beam deflection and both axial and transverse shear stresses are affected by the variation of volume fraction index and beam length-to-height ratio. Results of the numerical analysis have been reported and compared with those available in the open literature to evaluate the accuracy and robustness of the proposed finite element model. The comparisons with other higher order shear deformation theories verify that the proposed beam element is accurate, presents fast rate of convergence to the reference results and it is also valid for both thin and thick functionally graded sandwich beams. Further, some new results are reported in the current study, which will serve as a benchmark for future research.


2014 ◽  
Vol 697 ◽  
pp. 181-186
Author(s):  
Zi Lei Wang ◽  
Tian De Qiu

The piezoelectric field and structure field of piezoelectric resonator of ultrasonic motor are intercoupling. It is difficult to obtain the solution under some circumstances because of the complex stress boundary condition and the influence of coupling effect. An electro-mechanical coupling finite-element dynamic equation is established on the basis of the Hamilton’s Principle about piezoceramic and elastomer. The equation is decoupled through the shock excitation of the piezoelectric resonator and the piezoelectricity element and material provided by finite-element analysis. As a result, an admittance curve as well as the distribution status of the nodal DOF is obtained, which provides an effective method to solve electro-mechanical coupling problems.


Author(s):  
Alireza Doosthoseini ◽  
Armaghan Salehian ◽  
Matthew Daly

In this paper we focus on a study which involves quantifying the effects of Macro Fiber Composite (MFC) actuators on the pattern and magnitude of wrinkles in a membrane when exposed to various loadings. An ABAQUS finite element code is employed for this research. The membrane in this study has a rectangular shape which is clamped at one edge and is free to move in the horizontal direction at the other edge. MFC actuators are bounded to the membrane to make a bimorph configuration.


1991 ◽  
Vol 113 (3) ◽  
pp. 171-175 ◽  
Author(s):  
Y. W. Kwon ◽  
K. Y. Byun

An analysis model is presented to analyze continuous fiber-reinforced composite structures with some local damage such as matrix cracks. Two separate material properties of fiber and matrix are used in the analysis model instead of a smeared-out global anisotropic material property. Stresses acting on fibers and stresses acting on matrix are computed directly. If there are local matrix cracks in the direction perpendicular to the fiber orientation in a composite structure, the broken matrix is modeled not to sustain any tensile stress in the fiber direction. A finite element formulation is derived for the analysis model. Some numerical problems are presented to test the proposed analysis model.


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