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The recovery of the stress gradient in finite elements problems is a widely discussed topic with many applications in the design process. The stress gradient is related to the second derivative (Hessian) of the nodal displacements and numerical techniques are required for its calculation. Particular difficulties are encountered in the reconstruction of the stress gradient in the boundary regions of...
In the present study, the in-plane elastic stiffness coefficients of graphene within the framework of first strain gradient theory are calculated on the basis of an accurate molecular mechanics model. To this end, a Wigner–Seitz primitive cell is adopted. Additionally, the first strain gradient theory for graphene with trigonal crystal system is formulated and the relation between elastic stiffness...
Two initial-value problems are considered involving a parameter $$\alpha $$ α , the corresponding steady states have a critical value at $$\alpha =\alpha _c<0$$ α = α c < 0 with steady state solutions possible only if $$\alpha \ge \alpha _c$$ α ≥ α c . The aim is to compare how the solution to these two problems evolves in time. For the first problem we find that a solution...
The rolling contact problem of a non-homogeneous layer is considered here. The graded layer possesses a variable elastic modulus with an exponential distribution. The Poisons ratio is assumed to be constant. A rigid cylindrical indenter is rolling over the surface of the graded layer with a constant velocity. First, the Navier equations of equilibrium are solved in the Fourier domain. Later, the boundary...
Motivated from the need to convert time-dependent rheometry data into complex frequency response functions, this paper studies the frequency response function of the creep compliance that is coined the complex creep function. While for any physically realizable viscoelastic model the Fourier transform of the creep compliance diverges in the classical sense, the paper shows that the complex creep function,...
The reliable guided wave inspection techniques depend on the accurate understanding of dispersive properties. The classic finite element method has been proven to be very practical for modeling wave propagation in arbitrary waveguides. However, when it comes to modeling on complex geometries, it still has a major drawback: the geometric discrete errors and the high consumption of resources to improve...
In the present study, conjugate heat transfer of nanofluid in a wide microchannel with thick wall, by considering the velocity slip and temperature jump on the fluid–solid interface and also the effect of viscous dissipation is investigated. For numerical solution of velocity field, preconditioned lattice Boltzmann method (PLBM) based on standard LBM, and for temperature field, standard LBM are used...
In rolling production, the foil flatness quality is judged by detecting the lateral distribution of the front tension stress. Currently, because of the inaccuracy of the tension control model, there are still many flatness defects in foil rolling production. For the tension stress model of foil rolling, the primary problem is the inaccuracy of the metal lateral flow model. Therefore, based on Fleck’s...
Magneto-rheological elastomers (MRE), consisting of elastomeric matrix containing ferromagnetic particles, are a kind of smart material, whose mechanical properties are controllable via applied magnetic fields. In this paper, the possibility of adopting these materials to realize vibration isolators for lightweight structures is evaluated. Such isolators must be stiff enough in the vertical direction,...
In this paper, plane strain surface waves, also named generalized Rayleigh surface waves, in a transversely isotropic piezoelectric semiconductor half space are investigated. The governing equations of generalized Rayleigh surface waves include the equations of motion, Gauss’ law of electrostatics and the conservation of charge. Based on the basic theory of elastic-dynamic equations, the governing...
The problem of oblique water wave scattering by three thin vertical barriers in deep water is investigated here assuming linear theory. The geometrical configurations of the three barriers are such the inner(middle) barrier is partially immersed and the two outer barriers are completely submerged and extend infinitely downwards. A system of three simultaneous integral equations of first kind involving...
Thermal postbuckling analysis is presented for graphene-reinforced composite (GRC) laminated cylindrical shells under a uniform temperature field. The GRC layers are arranged in a functionally graded (FG) graphene reinforcement pattern by varying the graphene volume fraction in each GRC layer. The GRCs possess temperature dependent and anisotropic material properties and the extended Halpin–Tsai model...
Thermo-mechanical buckling and post-buckling analysis of arbitrary, smooth and folded shells with different boundary conditions are investigated. A pure displacement-and-theory-based isoparametric curved triangular shell element is introduced. This element is neither hybrid-mixed nor degenerated. Nevertheless, it is free from locking problem. The new element has six nodes while each node has three...
We study the effect of poroelasticity on fluid–structure interaction. More precisely, we analyze the role of fluid flow through a deformable porous matrix in the energy dissipation behavior of a poroelastic structure. For this purpose, we develop and use a nonlinear poroelastic computational model and apply it to the fluid–structure interaction simulations. We discretize the problem by means of the...
A modified version of Adomian decomposition method is presented and applied to solve linear elliptic differential equations in anisotropic domains in a recursive manner. A complementary constitutive decomposition, guided by a constitutive hierarchy, governs the superposition of the operator—a step of the Adomian’s method—and is defined as the original constitutive tensor being constructed by an isotropic...
The present paper explores two approaches which, based on the measurement of the two first natural frequencies, allow the identification of the tension force in cables with insulators. For this purpose, the nonlinear mathematical model of the mechanical system and its Finite Element discretization are firstly stated. Besides, free-vibrations experiments on both a laboratory and a real-scale simulated...
Wireless recharge of electric vehicles is an important field of research. Design of inductive power transfer systems involves the optimization of resonant coils coupled through mutually induced magnetic fields. Currently there is a big interest concerning both on optimization methods and on the research of innovative topologies able to maximize both power transfer and efficiency. In this work, authors...
We investigate propagation of waves in the Zener-type viscoelastic media through a model which involves fractional derivatives with a regular kernel. The restrictions on the coefficients in the constitutive equation that follow from the weak form of the dissipation principle are obtained. We formulate a problem of motion of a spatially one dimensional continuum in a dimensionless form. Then, it is...
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