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Surface texturing has been effectively used to improve tribological performance of sliding surfaces. Reduction in friction, increase in hydrodynamic load carrying capacity, reduction in wear and increase in fluid film stiffness are few examples of the benefits that can be obtained by surface texturing. In order to obtain these benefits, several researchers have investigated the effects of surface...
A three-dimensional system of differential equations is considered that describes a thermoelastic equilibrium of homogeneous isotropic elastic materials, microelements of which, in addition to classical displacements and thermal fields, are also characterized by microtemperatures. In the Cartesian system of coordinates the general solution of this system of equations is constructed using harmonic...
In this article pulsatile nature of blood flow through unsymmetric stenosed tapered artery in the presence of catheter has been modelled. Blood is represented by micropolar fluid. The analytical solutions for velocity and microrotation components are obtained in terms of Bessel functions of the first and second kind. Flow parameters such as the resistance to flow (impedance) in the artery and wall...
Locally-resonant (LR) phononic meta-materials and structures have a potential for wide band-gaps of elastic wave attenuation in low frequency range. In this paper, we investigate a use of continuum beam resonators suspended periodically on an Euler–Bernoulli beam. In a mathematical analysis based on Floquet–Bloch’s theorem, we describe the dispersive characteristics of flexural wave attenuation. Our...
The present work deals with the analysis of free and forced vibrations of double viscoelastic piezoelectric nanobeam systems (DVPNBSs) incorporating nonlocal viscoelasticity theory and Euler–Bernoulli beam model. The two viscoelastic piezoelectric nanobeams (VPNBs) are coupled by visco-Pasternak medium. Viscoelastic property of VPNBs is simulated by Kelvin–Voigt and Maxwell models. In order to obtain...
In this study, thermo-mechanical vibration analyzes of functionally graded (FG) beams made of porous material subjected various thermal loadings are carried out by presenting a Navier type solution and employing a semi analytical differential transform method (DTM) for the first time. Three types of thermal loadings, namely, uniform, linear and nonlinear temperature rises through the thickness direction...
Forced convection of laminar nearly incompressible gaseous slip flow over an isothermal flat plate at low Mach number with viscous dissipation is considered. The non-similar solutions of hydrodynamical and thermal boundary layers equations with velocity-slip and temperature-jump at the wall are obtained numerically by using the implicit finite difference method. The effects of the modified boundary...
The nonlinear size-dependent dynamics of a geometrically imperfect Timoshenko microbeam subject to an axial load is investigated numerically based on the modified couple stress theory. Increasing the compressive axial load leads to an increase in the deflection (bending) amplitude of the microbeam. A distributed harmonic excitation load in the transverse direction is then applied to the microbeam...
The rotordynamics of a double-helical gear transmission system is investigated. The equation of motion of the system with bearing and gyroscopic effect is derived by using the finite element method, in which Timoshenko beam finite element is used to represent the shaft, a rigid mass for the gear. Natural frequencies, mode shapes and Campbell diagrams are illustrated to indicate the effects of gear...
Eringen’s nonlocal parameter is estimated for single-walled carbon nanotubes (SWCNTs) with arbitrary chirality. Analytical solution is presented by using molecular mechanics and nonlocal elasticity theory. The model is used to elucidate the effect of tube chirality, tube diameter, aspect ratio of the nanotube (length/diameter) and wave propagation mode shapes on the magnitude of the nonlocal parameter...
Models of three-dimensional lattices with long-range interactions of Grünwald–Letnikov type for fractional gradient elasticity of non-local continuum are suggested. The lattice long-range interactions are described by fractional-order difference operators. Continuous limit of suggested three-dimensional lattice equations gives continuum differential equations with the Grünwald–Letnikov derivatives...
In this paper, analytical solution has been obtained for a functionally graded, transversely isotropic, thermoelastic thick walled hollow cylinder (or disk) subjected to a thermal source. The linear theory of generalized thermoelasticity (Lord–Shulman model) has been employed to model the problem. The material stiffness and thermal conductivity have been assumed to vary as a simple power of the radial...
An analysis is performed for fully developed free convection flow of a viscous fluid in a vertical channel including the effect of viscous dissipation for the cases of separated effect of variable viscosity, variable thermal conductivity and combined effect of variable viscosity and variable thermal conductivity. The viscosity of the fluid is assumed to depend on the temperature and the thermal conductivity...
The present paper deals with the effects of nanofluids and thermal radiation over a stretching/shrinking sheet. The governing differential equations are transformed into a set of non-linear coupled ordinary differential equations which are then solved using numerical technique with appropriate boundary conditions for various values of physical parameters. The effects of various physical parameters...
Two general mixed formulations, i.e., the pressure-based mixed Ritz-differential quadrature method and the potential-based mixed Ritz-differential quadrature method, are proposed to study the free and forced vibration of Timoshenko beams in contact with fluid. The proposed mixed methods use the Ritz method and the differential quadrature method to discretize the governing partial differential equation...
We have analyzed peristaltic flow of an Oldroyd-B fluid in a curved channel. Assuming the flow to be incompressible, laminar and two-dimensional, the governing partial differential equations are reduced under long wavelength and low Reynolds number approximations into a single nonlinear ordinary differential equation in the stream function. Matlab built-in routine bvp4c is utilized to solve this nonlinear...
Friction stir welding is one of the newest methods of metal welding. The method is constantly being developed and friction stir spot welding (FSSW) is one of its varieties. The method is mainly used in the aircraft, automotive and shipbuilding industries. During the process, heat is generated as a result of friction between the tool and materials as well as plastic deformation of the joined materials...
Structure weight is a priority issue in the transport industry, especially in aviation, therefore the demand for drawn parts made of titanium has grown steadily. Titanium in comparison to steel and aluminium has a much more beneficial specific strength so it is used where high mechanical strength and low construction weight are especially essential. In view of its high melting temperature, titanium...
In recent years thanks to enhancements in design of advanced machines, laser metrology and computer control, ultra-precision machining has become increasingly important. In micromachining of metals the depth of cut is usually less than the average grain size of a polycrystalline aggregate; hence, a cutting process can occur entirely within a single crystal. The respective effect of crystallographic...
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