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Showing papers on "Orthotropic material published in 2019"


Journal ArticleDOI
Abstract: The free vibration analysis of laminated nanocomposite plates and shells using first-order shear deformation theory and the generalized differential quadrature method is presented. Each layer of the laminate is modeled as a three-phase composite. An example of such composite material is given by a polymeric matrix reinforced with carbon nanotubes (CNTs). CNTs enhance the mechanical properties of the polymer matrix and the nanocomposite is treated as an isotropic material; a micromechanics model is used to compute the engineering constants of the isotropic hybrid material. This approach based on the Eshelby–Mori–Tanaka scheme takes into account the agglomeration of the nanoparticles in the matrix. The second step consists in combining this enriched matrix with unidirectional and oriented reinforcing fibers to obtain a fibrous composite with improved mechanical features. The overall mechanical properties of each orthotropic ply are evaluated through different micromechanics approaches. Each technique is illustrated in detail and the transversely isotropic properties of the three-phase layers are completely defined. The effects of both CNTs agglomeration and the mass fraction of these particles are investigated comparing with the results obtained by various homogenization techniques. POLYM. COMPOS., 2017. © 2017 Society of Plastics Engineers

139 citations


Journal ArticleDOI
TL;DR: In this paper, two theoretical models have been built to predict the tensile strength and Young's modulus of FDM additive manufacturing PLA material with different printing angles and layer thicknesses.

121 citations


Journal ArticleDOI
TL;DR: In this paper, a homogenization-based approach is proposed to perform compliance minimization and projection of coated structures with orthotropic infill material in 2D, where the design space is relaxed to allow for a composite material description, which means that designs with complex microstructures can be obtained on relatively coarse meshes.

96 citations


Journal ArticleDOI
TL;DR: In this article, the dynamic response of sandwich plates subjected to blast load was analyzed by considering the effect of various parameters such as structural damping, viscoelastic medium constants, geometric parameters of plates, volume fraction and agglomeration of CNTs, geometrical parameters of auxetic honeycombs core and magnetic field on the dynamic deflection of the sandwich structure.

69 citations


Journal ArticleDOI
TL;DR: In this paper, the role played by the orientation of the fiber and the inter-fiber spacing on the fracture pattern in the composite is investigated. But the main objectives of this work are: (a) to study the crack propagation path and (b) to investigate the influence of the fibre-matrix interface on the crack path.

52 citations


Journal ArticleDOI
TL;DR: In this paper, a numerical study of thermal-mechanical crack growth in orthotropic composite materials by the recently developed extended nodal gradient finite element method is presented, where the singularity and discontinuity of temperature, heat flux, and displacements due to the presence of crack are mathematically described through known enrichment functions.

45 citations


Journal ArticleDOI
TL;DR: In this article, the aerodynamic pressure and critical flutter speed for the viscoelastic orthotropic cylindrical shells are determined by a numerical method based on the elimination of the singularity in the relaxation kernel of the integral operator.

44 citations


Journal ArticleDOI
TL;DR: In this paper, a peridynamic model is proposed for quantitative elastic and fracture analysis of orthotropic materials, which is capable of capturing fracture characteristics (i.e., crack path, energy concentration, displacement-load relationship, and energy balance during crack propagation) as demonstrated in both the compact tension and single edge-notched tension (SENT) tests.

42 citations


Journal ArticleDOI
TL;DR: The results show that the magnetic field to the facesheets can be considered as effective parameters to control the dynamic deflection of the structure and lead to increase of 24% in the dynamic displacement of system.
Abstract: The current work suggests a mathematical model for the dynamic response of sandwich plates subjected to a blast load using a numerical method. The sandwich structure is made from an auxetic honeycomb core layer integrated by multiphase nanocomposite facesheets. The facesheets are composed of polymer–carbon nanotube (CNT)–fiber where the equivalent material properties of the multiphase nanocomposite layers are obtained using fiber micromechanics and Halpin–Tsai equations in hierarchy. The top and bottom layers are subjected to magnetic field and the material properties of them are assumed temperature and moisture dependent. The Kelvin–Voigt model is employed to consider the viscoelastic properties of the structure. The sandwich structure is rested on a viscoelastic foundation which is modeled by orthotropic visco-Pasternak medium. Based on refined zigzag theory (RZT), energy method and Hamilton’s principle, the motion equations are derived. A new numerical method, namely differential cubature method (DCM) in conjunction with Newmark method is utilized for obtaining the dynamic deflection of the structure for different boundary conditions. The effects of various parameters such as blast load, viscoelastic foundation, structural damping, magnetic field, volume fraction of CNTs, temperature and moisture changes, geometrical parameters of honeycomb layer and sandwich plate are considered on the dynamic deflection of the structure. The results show that the magnetic field to the facesheets can be considered as effective parameters to control the dynamic deflection. In addition, hygrothermal condition leads to increase of 24% in the dynamic displacement of system.

40 citations


Journal ArticleDOI
TL;DR: In this paper, the effect of thermal loadings on the stress intensity factor of an edge crack of finite length in an orthotropic infinite strip of finite thickness under mechanical loading was determined, and the results were presented in the form of graphs.
Abstract: The purpose of this article is to determine the effect of thermal loadings on the stress intensity factor of an edge crack of finite length in an orthotropic infinite strip of finite thickness under mechanical loading. Analytical expressions of the stress intensity factor at the crack tip in point and arbitrary constant loadings are found. Numerical values of the factor at any arbitrary location on the crack face due to mechanical loading and effects of thermal loadings are computed for various crack lengths in an orthotropic material composite, and the results are presented in the form of graphs. The effects of thermal conductivity parameters on the stress intensity factor for different particular cases are also shown graphically.

37 citations


Journal ArticleDOI
TL;DR: In this article, a conformal mapping function is used to map an infinite plate containing a rectangular hole into the outside of a unit circle and stress and displacement distributions around the rectangular hole in an orthotropic infinite plate are investigated in thermal steady state condition.
Abstract: One of the most important issues in the design of engineering structures is the prevention of structural failure due to the stress caused by geometric discontinuities . Hole geometry is one of the effective parameters in the distribution of stress and displacement around it. In this study, using the two-dimensional thermoelastic theory and based on the Likhnitskiiʼ complex variable technique, the stress analysis of orthotropic infinite plate with a circular hole under a uniform heat flux is developed to the plate containing a rectangular hole. To achieve this goal, a conformal mapping function is used to map an infinite plate containing a rectangular hole into the outside of a unit circle. Stress and displacement distributions around the rectangular hole in an orthotropic infinite plate are investigated in thermal steady state condition. The plate is under uniform heat flux at infinity and Neumann boundary conditions and thermal-insulated condition at the edge of the hole are considered. The rotation angle of the hole, fiber angle, the flux angle, bluntness and the aspect ratio of hole size are important parameters investigated in the present study. The obtained results show that these parameters have a significant effect on the stress and displacement distributions around the rectangular hole.

Journal ArticleDOI
TL;DR: In this paper, a general and extended minimum strain energy density criterion for orthotropic materials with unidirectional fibers is employed to anticipate the onset of crack growth, and a new concept of critical stress intensity factor is defined and formulated for arbitrary inclination cracks with respect to the fibers.

Journal ArticleDOI
TL;DR: In this paper, the static analysis of Kirchhoff nano plates subjected to uniformly (UDL) and sinusoidally (SSL) distributed load is computed, and the strain gradient nonlocal theory has been employed in order to involve the size effects of nanostructures in classical continuum theory.
Abstract: The static analysis of Kirchhoff nano plates subjected to uniformly (UDL) and sinusoidally (SSL) distributed load is computed. The strain gradient nonlocal theory has been employed in order to involve the size effects of nanostructures in classical continuum theory. The governing equation of motion of Kirchhoff in weak form are applied to nano plates, involving second-order strain gradient nonlocal theory. Thus, the obtained partial differential equations have an increased order of derivation respect to the classical theory, from the fourth to the sixth. The displacements are carried out following the Navier procedure for simply supported boundary conditions. Isotropic and antisymmetric orthotropic laminates, both cross- and angle-ply are studied, for different layouts involving different material properties. Dimensionless outcomes in terms of transverse displacements, and normal and shear stresses, are given to changing aspect ratio and non local ratio, also making a comparison with the classical theory.

Journal ArticleDOI
TL;DR: In this paper, an orthotropic model for in-plane linear elasticity is proposed in the micropolar peridynamic analysis framework, which is derived from the definition of a specific microelastic energy function for micropolastic nonlocal lattices.

Journal ArticleDOI
TL;DR: In this article, the elastic properties of a large panel of lattice architectures using a continuous description of geometry are investigated, and the elastic constants of the orthotropic material are determined, and discussed in terms of specific stiffness and of its density dependence.

Journal ArticleDOI
TL;DR: The aim of the present work was to investigate the mechanical behavior of orthotropic composites, such as masonry assemblies, subjected to localized loads described as micropolar materials, as well as the significant role played by the relative rotation.
Abstract: The aim of the present work was to investigate the mechanical behavior of orthotropic composites, such as masonry assemblies, subjected to localized loads described as micropolar materials. Micropolar models are known to be effective in modeling the actual behavior of microstructured solids in the presence of localized loads or geometrical discontinuities. This is due to the introduction of an additional degree of freedom (the micro-rotation) in the kinematic model, if compared to the classical continuum and the related strain and stress measures. In particular, it was shown in the literature that brick/block masonry can be satisfactorily modeled as a micropolar continuum, and here it is assumed as a reference orthotropic composite material. The in-plane elastic response of panels made of orthotropic arrangements of bricks of different sizes is analyzed herein. Numerical simulations are provided by comparing weak and strong finite element formulations. The scale effect is investigated, as well as the significant role played by the relative rotation, which is a peculiar strain measure of micropolar continua related to the non-symmetry of strain and work-conjugated stress. In particular, the anisotropic effects accounting for the micropolar moduli, related to the variation of microstructure internal sizes, are highlighted.

Journal ArticleDOI
TL;DR: In this paper, the authors developed a closed-form solution for the free vibration problem of inhomogeneous orthotropic rectangular plates (IHORPs) resting on the inhomogenous viscoelastic foundation.
Abstract: The paper developed the closed-form solution for the free vibration problem of inhomogeneous orthotropic rectangular plates (IHORPs) resting on the inhomogeneous viscoelastic foundation (IHVEF). Th...

Journal ArticleDOI
TL;DR: In this article, the 3D corrugated-core plate is converted to a 2D orthotropic continuum model by considering some equivalent elastic constants, and the geometric and mechanical factors influencing their responses, such as displacements, rotations, moments and shear forces, are evaluated.

Journal ArticleDOI
TL;DR: In this paper, a 3D exact hygrothermal elasticity solution is developed to study the behavior of simply supported rectangular multilayered composite plates, considering any combination of orthotropic and/or isotropic layers, under hygro-thermo-mechanical loadings.

Journal ArticleDOI
TL;DR: In this article, the authors proposed an efficient computational methodology to predict effective orthotropic elastic properties of nanocomposites at diverse constituent conditions, including elastic, elastoplastic and interfacial behavior.
Abstract: The CNT based nano-composites usually behave as anisotropic materials. Elastic properties vary differently in global as well as material direction. This paper proposes an efficient computational methodology to predict effective orthotropic elastic properties of nanocomposites at diverse constituent conditions. The effective orthotropic material properties have been presented with the consideration of all possible conditions of composite matrix like elastic, elastoplastic and interfacial behavior. Mori-Tanaka (MT) homogenization scheme has been implemented with finite element method (FEM) approach to predict the effective material properties of nanocomposites. In the presented study, CNTs are aligned and uniformly distributed throughout the composite matrix. The proposed computational methodology has been validated with available literature and further extended to investigate the effect of the diverse behavior of composite matrix. From the obtained numerical results, it has been seen that the matrix and filler interface significantly affect the effective elastic strength of polymer composites.

Journal ArticleDOI
TL;DR: In this paper, an orthotropic hyperelastic strain energy function (SEF) and associated nonlinear constitutive theory was proposed to describe the response of transversely isotropic and orthotropic neo-Hookean materials under a range of physical deformations in which the strains are large.

Journal ArticleDOI
TL;DR: In this article, the adaptive extended isogeometric analysis (XIGA) based on locally refined (LR) B-splines is developed for cracked orthotropic composite structures by using an efficient computational approach.
Abstract: This paper is concerned with the numerical investigation of fracture mechanics parameters for cracked orthotropic composite structures by using an efficient computational approach. The adaptive extended isogeometric analysis (XIGA) based on locally refined (LR) B-splines is thus developed. This adaptive XIGA is enhanced by both signed-distance and orthotropic crack-tip enrichment functions to represent strong discontinuity and singularity induced by crack, respectively. In addition, to improve the integration accuracy, the ‘sub-triangle’ and ‘almost polar’ techniques are adopted for the cut and crack tip elements, respectively. For adaptivity, the smoothed stress field is achieved to develop the posteriori error estimator based local refinement, according to the Zienkiewicz–Zhu estimation. Such posteriori error estimator is then used to determine refinement domains, where the local refinement takes place. The proposed approach is applied for fracture analyses of orthotropic composites, in which the stress intensity factors (SIFs) are evaluated using the contour interaction integral technique. The accuracy of the proposed adaptive orthotropic XIGA is validated through a comparison of SIFs obtained from the proposed method and the available reference solutions. Furthermore, numerical results show that the convergence rate of the adaptive local refinement is faster than that of the global refinement approach.

Journal ArticleDOI
TL;DR: In this article, a two-dimensional generalized thermoelasticity with memory-dependent derivatives (MDDs) is considered in homogeneous orthotropic medium in the context of generalization.
Abstract: The present article deals with a two-dimensional problem of generalized thermoelasticity with memory-dependent derivatives (MDDs). The problem is considered in homogeneous orthotropic medium in the...

Journal ArticleDOI
TL;DR: In this paper, an experimental-cum-numerical methodology for the characterization of 3D-printed polycarbonate-acrylonitrile butadiene styrene (PC-ABS) was presented.

Journal ArticleDOI
TL;DR: In this article, the Yld2004-18p function is revisited and modified to provide satisfactory predictability of orthotropic behavior of body-centered cubic (BCC) materials under spatial loading with reduced experimental costs.

Journal ArticleDOI
TL;DR: In this article, simple closed-form expressions for linear elastic constants of regular brick pattern masonry, solicited in their plane, are derived by means of a homogenization procedure.

Journal ArticleDOI
TL;DR: In this article, the elastic bending analysis of transversely loaded shear-deformable rectilinear orthotropic composite annular plates is performed based on the virtual displacements principle.
Abstract: This work outlines the elastic bending analysis of transversely loaded shear-deformable rectilinear orthotropic composite annular plates. The load condition discussed in the paper, along with the displacement constraints, are derived by the composite bolted joints theoretical reference model – this analytical solution is a necessary effort for the obtainment of a custom finite element capable of simulating this kind of joints with high accuracy and limited computational effort. Firstly, the constitutive equations of the family of plate under investigation are obtained in the framework of the First-order Shear Deformation Plate Theory. The described methodology is founded on the application of the virtual displacements principle and its solution is performed according to Ritz method after the writing of displacement field approximation functions fulfilling the boundary conditions. The three unknown displacement components are obtained for different case studies concerning rectilinear orthotropic composite annular plates featuring various slenderness ratios, shape factors and stacking sequences. The outcomes comparison with FE numerical solutions evidences a high degree of fidelity. The presented results demonstrate that this enhanced version of the Ritz analytical solution method, which accounts for the composite plate shear deformability, can be more effectively employed to describe the displacement field of composite plates connected by a bolted joint in the area surrounding the bolt.

Journal ArticleDOI
Zhang Jianping1, Shusen Wang1, Gong Shuguang1, Qing-Song Zuo1, Hu Huiyao1 
TL;DR: In this article, the authors established a computational model of thermo-mechanical coupling analysis for orthotropic structures based on the element-free Galerkin (EFG) method.
Abstract: The computational model of thermo-mechanical coupling analysis for orthotropic structures was established based on the element-free Galerkin (EFG) method. The computational method and programs was verified through engineering thermoelastic problems of complex orthotropic structures. The influence of off-angle and the orthotropic material factors including thermal conductivity orthotropic factor, thermal expansion orthotropic factor, Poisson's ratio factor on the thermal deformation and thermal stress was investigated, and the reasonable range of these parameters was provided. A group of these preferred parameters were used to finish the thermo-mechanical coupling analysis of the orthotropic structure by using the proposed model and the results show that the maximum value of thermal deformation and thermal stress for orthotropic structure is reduced by 11% and 24% compared with the isotropic structure, respectively. The EFG solutions show a higher calculation precision than the finite element method (FEM) solutions in practical orthotropic thermoelastic problems. The off-angle affects the magnitude and direction of total thermal deformation displacement and the magnitude of Mises stress, while orthotropic materials factors only affect the magnitude of total thermal deformation displacement and the Mises stress without affecting the direction. The reasonable off-angle and orthotropic material factors can effectively improve thermal deformation and thermal stress.

Journal ArticleDOI
TL;DR: In this article, an analytical method is presented to investigate the nonlinear dynamic behavior of corrugated graphene/piezoelectric (CGP) laminated structures under electro-mechanical coupling loads, where the corrugation graphene is affixed on a piezelectric film, and its accuracy is validated by the finite element method.

Journal ArticleDOI
TL;DR: This new orthotropic model enables realistic simulations of textile membranes in a fully geometrically nonlinear setting, which does not require simplifications based on linearized strains, which are currently used as standard in engineering practice.