- Dettagli della rivista
- Formato
- Rivista
- eISSN
- 2353-9003
- Pubblicato per la prima volta
- 19 Apr 2013
- Periodo di pubblicazione
- 4 volte all'anno
- Lingue
- Inglese

#### Cerca

Accesso libero

#### Finite Element Dynamic Analysis Of Non-Uniform Beams On Variable One-Parameter Foundation Subjected To Uniformly Distributed Moving Loads

Pagine: 693 - 715

#### Astratto

A general numerical analysis theory capable of describing the behaviour of a non-uniform beam resting on variable one parameter (Winkler) foundation under a uniform partially distributed moving load is developed. The versatile numerical solution technique employed is based on the finite element and Newmark integration methods. The analysis is carried out in order to evaluate the effect of the following parameters (i) the speed of the moving load (ii) the span length of the beam (iii) two types of vibrating configurations of the beam (iv) the load’s length and (v) the elastic foundation modulus, on the dynamic behaviour of the non-uniform beam resting on the variable one-parameter foundation. Numerical examples which showed that the above parameters have significant effects on the dynamic behaviour of the moving load problem are presented.

#### Parole chiave

- finite element
- dynamic analysis
- non-uniform beams
- one-parameter foundation

Accesso libero

#### Plane Strain Deformation In A Thermoelastic Microelongated Solid With Internal Heat Source

Pagine: 717 - 731

#### Astratto

The purpose of this paper is to study the two dimensional deformation due to an internal heat source in a thermoelastic microelongated solid. A mechanical force is applied along an overlaying elastic layer of thickness

#### Parole chiave

- thermoelasticity
- microelongation
- heat source
- normal mode analysis

Accesso libero

#### Numerical Study Of The Heat Transfer Phenomenon Of A Rectangular Plate Including Void, Notch Using Finite Difference Technique

Pagine: 733 - 756

#### Astratto

In the present study, we have developed a code using Matlab software for solving a rectangular aluminum plate having void, notch, at different boundary conditions discretizing a two dimensional (2D) heat conduction equation by the finite difference technique. We have solved a 2D mixed boundary heat conduction problem analytically using Fourier integrals (Deb Nath

#### Parole chiave

- transient
- steady state
- finite-difference method
- analytical method
- rectangular plate
- void
- notch

Accesso libero

#### Review Of Applied Mathematical Models For Describing The Behaviour Of Aqueous Humor In Eye Structures

Pagine: 757 - 772

#### Astratto

In the paper, currently used methods for modeling the flow of the aqueous humor through eye structures are presented. Then a computational model based on rheological models of Newtonian and non-Newtonian fluids is proposed. The proposed model may be used for modeling the flow of the aqueous humor through the trabecular meshwork. The trabecular meshwork is modeled as an array of rectilinear parallel capillary tubes. The flow of Newtonian and non-Newtonian fluids is considered. As a results of discussion mathematical equations of permeability of porous media and velocity of fluid flow through porous media have been received.

#### Parole chiave

- porous medium
- Newtonian fluid
- non-Newtonian fluid
- coupe stress fluid
- generalized second grade fluid
- Darcy’s rule
- aqueous humor flow
- trabecular meshwork
- intraocular pressure
- glaucoma

Accesso libero

#### Impact Of The Pulse Width Modulation On The Temperature Distribution In The Armature Of A Solenoid Valve

Pagine: 773 - 786

#### Astratto

In order to estimate the inductive power set in the armature of the high-speed solenoid valve (HSV) during the open loop control (OLC) using pulse width modulation (PWM) an analytical explicit formula has been derived. The simplifications taken both in the geometry and in the physical behavior of the HSV were described. The inductive power was calculated for different boundary conditions and shown as a function of the frequency of the coil current. The power set in the armature was used as an input to the thermal calculation. The thermal calculation had an objective to estimate the time dependent temperature distribution in the armature of the HSV. All the derivation steps were presented and the influence of different boundary conditions was shown and discussed. The increase of the temperature during the heating with inductive power has been evaluated both in the core and on the side surface of the HSV.

#### Parole chiave

- solenoid valve
- armature
- inductive power
- PWM
- temperature

Accesso libero

#### Transient Velocity And Steady State Entropy Generation In A Microfluidic Couette Flow Containing Charged Nano Particles

Pagine: 787 - 804

#### Astratto

An analysis has been provided to determine the transient velocity and steady state entropy generation in a microfluidic Couette flow influenced by electro-kinetic effect of charged nanoparticles. The equation for calculating the Couette flow velocity profile is derived for transient flow. The solutions for momentum and energy equations are used to get the exact solution for the dimensionless velocity ratio and dimensionless entropy generation number. The effects of the dimensionless entropy generation number, Bejan number, irreversibility ratio, entropy generation due to fluid friction and due to heat transfer on dimensionless time, relative channel height, Brinkman number, dimensionless temperature ratio, nanoparticle volume fraction are analyzed.

#### Parole chiave

- transient velocity
- steady state entropy generation
- microfluidic Couette flow
- charged nanoparticles
- Bejan number and Brinkman number

Accesso libero

#### Cable-Stayed Cantilever Structures As An Expat Of Unique Application In The Construction Of A Building Located In Seismic Area – An Author’s Project Of Multifunctional Building In Lisbon, Portugal

Pagine: 805 - 816

#### Astratto

The article presents numerical simulations for the modelling of seismic impact on the structure of unique cantilever cablestayed structure with the application of two methods. The Response Spectrum method, in which a spectrum of the structure’s responses to an earthquake’s impact is generated, and the Accelerogram method, in which we generate dynamic load in the form of a diagram of the connection between acceleration and time for the actual readings during a real earthquake. Both methods have been presented for the El Centro earthquake spectrum. This unique application of a cantilever cablestayed structure in public buildings will allow to assess the safety of this kind of load-bearing system in areas of increased risk of seismic activity. Cantilever cablestayed structures have so far never been designed or analyzed on seismically active areas. Based on numerical simulation we determined the effect of stiffness of load-bearing lines on the increase of stresses and displacements at cable stays joint with the end of the cantilever part of a building.

#### Parole chiave

- cantilever structures
- seismic and dynamic analysis
- cable-stayed structures

Accesso libero

#### Radiation Effect On Three Dimensional Vertical Channel Flow Through Porous Medium

Pagine: 817 - 833

#### Astratto

The flow of a viscous incompressible fluid through a vertical channel in the presence of radiation immersed in a porous medium has been studied. Approximate solutions have been obtained for the velocity and temperature fields, shear stresses and rate of heat transfer using the perturbation technique. It is found that the primary velocity decreases with an increase in the radiation parameter as well as the Prandtl number for cooling of the plate. It is also found that with an increase in the permeability parameter, the primary velocity increases for cooling of the plate. The magnitude of the secondary velocity decreases near the plate

#### Parole chiave

- three-dimensional
- injection
- periodic suction
- permeability
- porous medium

Accesso libero

#### The Effect Of Randomness On The Stability Of Capillary Gravity Waves In The Presence Of Air Flowing Over Water

Pagine: 835 - 855

#### Astratto

A nonlinear spectral transport equation for the narrow band Gaussian random surface wave trains is derived from a fourth order nonlinear evolution equation, which is a good starting point for the study of nonlinear water waves. The effect of randomness on the stability of deep water capillary gravity waves in the presence of air flowing over water is investigated. The stability is then considered for an initial homogenous wave spectrum having a simple normal form to small oblique long wave length perturbations for a range of spectral widths. An expression for the growth rate of instability is obtained; in which a higher order contribution comes from the fourth order term in the evolution equation, which is responsible for wave induced mean flow. This higher order contribution produces a decrease in the growth rate. The growth rate of instability is found to decrease with the increase of spectral width and the instability disappears if the spectral width increases beyond a certain critical value, which is not influenced by the fourth order term in the evolution equation.

#### Parole chiave

- capillary gravity waves
- randomness
- evolution equation
- instability

#### AMS Mathematics subject classification:

- 76B15
- 76E17

#### Astratto

This paper reports some results of turbulent boundary layer computation. The calculation is made assuming that law of the wall is valid throughout the boundary layer. Simple relations are proposed for friction for a smooth pipe and a flat plate at zero incidence. The results are compared with recent measurements. Encouraging results are obtained for both the cases of flows.

#### Parole chiave

- boundary layer
- flat plate
- friction factor
- skin friction

Accesso libero

#### Mixed Convection In The Stagnation-Point Flow Over A Vertical Stretching Sheet In The Presence Of Thermal Radiation

Pagine: 871 - 888

#### Astratto

An unsteady two-dimensional stagnation-point mixed convection flow of a viscous, incompressible dusty fluid towards a vertical stretching sheet has been examined. The stretching velocity and the free stream velocity are assumed to vary linearly with the distance from the stagnation point. The problem is analyzed using similarity solutions. The similarity ordinary differential equations were then solved numerical by using the RKF-45 method. The effects of various physical parameters on the velocity profile and skin-friction coefficient are also discussed in this paper. Some important findings reported in this work reveal that the effect of radiation has a significant impact on controlling the rate of heat transfer in the boundary layer region.

#### Parole chiave

- boundary layer flow
- stretching porous surface
- mixed convective parameter
- thermal radiation
- numerical solution
- dusty fluid
- free stream velocity

#### AMS Subject Classification (2000):

- 76T15
- 80A20

Accesso libero

#### Stability Of Superposed Fluids Through Magnetic Field With Suspended Particles Of Different Permeability Saturated Through Porous Layer

Pagine: 889 - 898

#### Astratto

The instability of plane interface between two superposed Rivlin-Ericksen elastico-viscous fluids saturated through a porous medium has been studied to include the suspended (dust) particles effect. Following the linearized stability theory and normal mode analysis the dispersion relation is obtained. For stationary convection, the Rivlin-Ericksen elastico-viscous fluid behaves like Newtonian fluids. It found that for a potentially stable arrangement the Rivlin-Ericksen elastico-viscous fluid of different permeabilities in the presence of suspended particles in a porous medium is stable, whereas in a potentially unstable case instability of the system occurs. In the presence of a magnetic field for a potentially stable arrangement the system is always stable and for the potentially unstable arrangement, the magnetic field succeeds in stabilizing certain wave-number band which was unstable in the absence of the magnetic field.

#### Parole chiave

- porous medium
- suspended particles
- Rivlin-Ericksen fluid and magnetic field

Accesso libero

#### Parametric Studies Of Failure Mechanisms In Thermal Barrier Coatings During Thermal Cycling Using FEM

Pagine: 899 - 915

#### Astratto

Thermal barrier coatings (TBCs) are widely used on different hot components of gas turbine engines such as blades and vanes. Although, several mechanisms for the failure of the TBCs have been suggested, it is largely accepted that the durability of these coatings is primarily determined by the residual stresses that are developed during the thermal cycling. In the present study, the residual stress build-up in an electron beam physical vapour deposition (EB-PVD) based TBCs on a coupon during thermal cycling has been studied by varying three parameters such as the cooling rate, TBC thickness and substrate thickness. A two-dimensional thermomechanical generalized plane strain finite element simulations have been performed for thousand cycles. It was observed that these variations change the stress profile significantly and the stress severity factor increases non-linearly. Overall, the predictions of the model agree with reported experimental results and help in predicting the failure mechanisms.

#### Parole chiave

- thermal barrier coatings
- residual stress
- failure mechanisms
- modeling and simulation

Accesso libero

#### Conditions Of Stability Loss During The Test Of Hydraulic Forming Of Drawpieces

Pagine: 917 - 938

#### Astratto

The paper contains two parts. In the first part, basic relationships were derived and some problems connected with stability loss during hydraulic forming of round metallic drawpieces with liquid pressure were discussed. The aim of the considerations is to test drawability of sheets by estimation of acceptable values of plastic strains and the corresponding heights of spherical shells. The analysis was based on some selected real conditions of stability loss. The influence of the coefficient of material hardening for the drawpiece, the coefficient of normal anisotropy and coefficients of plane anisotropy on acceptable values of plastic strains and heights of the formed drawpieces corresponding to the given condition of stability loss was also tested.

#### Parole chiave

- hydraulic forming
- stability loss
- boundary strains
- height of drawpieces
- normal and plane anisotropy

Accesso libero

#### Green’s Function In Free Axisymmetric Vibration Analysis Of Annular Thin Plates With Different Boundary Conditions

Pagine: 939 - 951

#### Astratto

Free vibration analysis of homogeneous and isotropic annular thin plates by using Green’s functions is considered. The formula of the influence function for uniform thin circular and annular plates is presented in closed-form. The limited independent solutions of differential Euler equation were expanded in the Neumann power series based on properties of integral equations. The analytical frequency equations as power series were obtained using the method of successive approximations. The natural axisymmetric frequencies for singularities when the core radius approaches zero are calculated. The results are compared with selected results presented in the literature.

#### Parole chiave

- annular plates
- Green’s function
- singularities

Accesso libero

#### Report: on the 14^{th} IFToMM 2015 WORLD CONGRESS - (International Federation for the Promotion of Mechanism and Machine Science IFToMM) which was HELD ON OCTOBER 25 - 30, 2015, TAIPEI, TAIWAN

Pagine: I - VI