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The purpose of this paper is to investigate steady state creep behavior of a functionally graded rotating disc under varying thermal gradient (TG).

The steady state creep in a rotating FGM disc with linearly varying thickness has been investigated by using von-Mises yield criterion. The disc under investigation is assumed to be made of FGM containing non-linear distribution of silicon carbide particle (SiC_p) in a matrix of pure aluminum along the radial distance. The creep behavior of the FGM composite disc is described by threshold stress-based law. The stresses and strain rates in the FGM disc have been estimated for different kinds of TG.

The results indicate that when the FGM disc is subjected to a radial TG, with temperature increasing with increasing radius, the radial stress in the disc increases over the entire disc but the tangential and effective stresses increase near the inner radius and decrease toward the outer radius. The imposition of such a radial TG in the FGM disc leads to significant reduction in the radial and tangential strain rates. With the increase in magnitude of TG in the FGM disc, the inhomogeneity in creep stresses increases but the inhomogeneity in strain rates decreases significantly, thereby reducing the chances of distortion in the FGM disc.

The creep strain rates in rotating FGM disc could be significantly reduced when the disc is subjected to a radial TG, with temperature increasing with increasing radius.

The purpose of this paper is to investigate the effect of anisotropy in terms of a single parameter indicating strengthening or weakening in the tangential direction in composite disc with hyperbolically varying thickness introduced presumably by processing or due to alignment of dispersed reinforcements during flow of the matrix.

Mathematical model to describe steady-state creep behavior in an anisotropic rotating disc made of Al-SiCp composite containing 30 vol% of SiC particles. The creep behavior of the composite has been described by Sherby's law. The creep parameters in the law have been determined using the regression equations developed on the basis of available experimental results in the literature. Stress and strain rate distributions for isotropic disc (a=1) have been compared with those obtained for anisotropic composites with characteristic parameters a=0.7 and 1.3.

The study revealed that the change in the stresses by anisotropy in composite disc is relatively small while anisotropy introduces significant change in the strain rates. It is concluded that the radial strain rate always remained compressive for the isotropic composite as well as the anisotropic disc with a greater than unity (a=1.3). However, it becomes tensile in the middle region of the disc when it is less than unity (a=0.7). If a is reduced from 1.3 to 0.7, the variation of tensile strain rate in the tangential direction remains similar, but the magnitude reduces, i.e. the strength in tangential direction is enhanced.

This study puts forward an analytical framework for the analysis of creep stresses and creep rates in an anisotropic rotating disc with hyperbolically varying thickness.

A mathematical model has been developed to predict steady state creep response of a rotating disc made of SiC (particle/whisker) reinforced 6061Al matrix composite. The model is used to investigate the effect of SiC morphology on the creep behavior of composite disc. The steady state creep behavior has been described by Sherby’s creep law. The creep stresses and creep rates are significantly affected by the morphology of SiC. The steady state creep rates in whisker reinforced disc are observed to be significantly lower than those observed in particle reinforced disc.

The purpose of this paper is to investigate the effect of imposing linear and quadratic composition gradients on the steady state creep behavior of a rotating functionally graded Al‐SiC_P disc operating under a radial thermal gradient.

Mathematical model to describe steady state creep behavior in rotating discs made of isotropic aluminum composite containing linear and quadratic distributions of Silicon Carbide (SiC_P) in the radial direction has been formulated. The discs are assumed to operate under a radial thermal gradient originating due to braking action as estimated by FEM analysis. The steady state creep behavior of the discs under stresses developing due to rotation has been determined following Sherby's law. Based on the developed model, the distributions of stresses and strain rates have been obtained and compared for various functionally graded material (FGM) discs containing the same average amount (20 vol per cent) of dispersoid. The creep response of a composite disc with uniform SiC_P content of 20 vol per cent and operating under a radial thermal gradient has also been computed for comparison with the results obtained for FGM discs.

The study reveals that the distribution of stresses and strain rates in a rotating composite disc operating under a radial thermal gradient are significantly affected by different particle distributions with in the disc. The creep stresses and steady state creep rates in a rotating FGM disc can be significantly reduced by employing more SiC_P particles in the middle compared to the inner and the outer radii.

The study provides an understanding of the required tailoring of composition in order to control creep stresses and creep rates in a rotating FGM disc operating under a radial thermal gradient.

This paper aims to explore the capabilities of artificial neural network (ANN) for predicting the creep response of a rotating Al‐SiC_P composite disc operating at elevated temperature.

Mathematical modeling of the steady state creep behavior, as described by Sherby's law, of a rotating disc made of isotropic aluminium‐silicon carbide particulate composite has been carried out. The creep response has been calculated for various combinations of particle size, particle content and temperature by extracting creep parameters from the limited experimental creep data available on similar material. The results thus obtained are used to train the ANN based on back propagation learning algorithm with particle size, particle content and temperature as input and stress and strain rates as output parameters. The trained network is used to predict the stresses and strain rates in the disc for the data set not covered in the training of network. The predictions obtained from the ANN model have been compared with the corresponding analytical values.

A nice agreement between the ANN predicted and analytical values of the creep stresses and strain rates has been observed.

ANN can be used as a reliable tool for investigating the effect of operating temperature and, reinforcement‐size and ‐content, on the creep behavior of a rotating composite disc to reach at optimum design code.

Rotating flows are very important because they are found in industrial and domestic applications. For a good performance, it is important to dimension correctly the energy efficiency and the lifespan of the apparatuses while studying, for example, the influence of their physical and geometrical characteristics on the various hydrodynamic constraints, thermal and mechanics which they will support. The purpose of this paper is to describe experiments and a numerical study of the inter‐disc space effects on the mean and the turbulent characteristics of a Von Karman isotherm steady flow between counter‐rotating disks.

Experimental results are obtained by the laser Doppler anemometer technique performed at IRPHE (Institute of Research on the Phenomena out Equilibrium) in Marseille, France. The numerical predictions are based on one‐point statistical modeling using a low Reynolds number second‐order full stress transport closure (RSM model).

It was found that the level of radial velocity increases with the aspect ratio near to the axis of rotation but this phenomenon is reversed far from this zone; the level of tangential velocity, of turbulence kinetic energy and of the torsion are definitely higher for the largest aspect ratio. The best contribution of this work is, at the same time, the new experimental and numerical database giving the effect of the aspect ratio of the cavity on the intensity of turbulence for Von Karman flow between two counter rotating disks.

The limitation of this work is that it concerns rotating flows with very high speeds because the phenomena of instability appear and the application of this model for cavities of forms is not obvious.

This work is of technological interest; it can be exploited by industrialists to optimize the operation of certain machines using this kind of flow. It can be exploited in the teaching of certain units of Masters courses: gathering experimental techniques; numerical methods; and theoretical knowledge.

This work can also have a social interest where this kind of simulation can be generalized with other types of flows responsible for certain phenomena of society, such as the phenomenon of pollution. This work can have a direct impact on everyday life by the exploitation of the rotary flows, such as being a very clean and very economic means to separate the undesirable components present in certain fluid effluents.

The best contribution of this work is the new experimental and numerical database giving the effect of the aspect ratio of the cavity on the intensity of turbulence for Von Karman flow between two counter rotating disks.

The present findings report a significant influence of disc profile and thickness on the order of excitation leading to critical speed condition. Certain transverse modes of vibration of the disc have been obtained to be more susceptible to get excited while recording the lowest critical speeds.

Numerical simulation using finite-element method has been adopted due to the complicated geometry, complex loadings and intricate analytical formulation. A comprehensive analysis of exclusive as well as combination of thermal and centrifugal loads has been taken up to determine the intensity and characteristics of the individual/combined effects.

The typical gas turbine disc profile has been analyzed to predict the critical speed under the factual working condition of an aero-engine. FEM analysis of uniform and variable thickness discs have been carried out under stationary, rotating and rotating-thermal considerations while emphasizing the effect of disc profile and thickness. Centrifugal stresses developed due to rotational effect result in unceasing stiffening of the discs with higher stiffening for a greater number of nodal diameters. On the other hand, a role reversal of thermal effect from stiffening to softening is figured out with increasing numbers of nodal diameters. However, the discs are subjected to an overall stiffening effect on account of the combined centrifugal and thermal loading, with the effect decreasing with an increase in disc thickness. Under the combined loading, the order of excitation leading to critical speed condition is dependent on disc profile and thickness. Moreover, the vibrational modes (0,1) and (0,2) are identified as more prominent adverse modes corresponding to lowest critical speeds.

The present findings are expected to serve as guidelines during the design phase of gas turbine discs of aeroengine applications.

The present work deliberates on the simulation and analysis of gas turbine disc specific to aeroengine application. The real-life disc geometry has been analyzed with due consideration of major factual operating conditions to identify the critical speed. The identification of various critical speed using numerical analysis can help to reduce the number of experimental tests required for certification.

A ROTATING PLASTIC DISC, such as a Frisbee, indicates high lift coefficients. To examine this phenomenon, experimental research was conducted, using a specially‐constructed rotating water tank. Test results demonstrated both lift increase and drag decrease for rotating discs compared to values for nonrotating discs.

The purpose of this paper is to establish a rigid–flexible coupling model of wind turbine disc brake to simulate the actual working condition of the wind turbine brake and to study the dynamic characteristics of the compensation mechanism under different friction coefficients and braking force. It provides reference for the structure design and optimization of the compensation mechanism (compensation brake wear) in the wind turbine brake.

Based on multi-body contact dynamics theory, the rigid‒flexible coupling dynamic model of wind turbine brakes with compensation mechanism is established, in which the contact process of the components in the compensation mechanism and the phenomenon of rotation and return are described dynamically, and the rotation angle of the compensation nut and the axial displacement response of the compensation screw are calculated under different parameters.

The analysis results show that the braking reliability of the brake compensation mechanism can be effectively improved by increasing the friction coefficient of threads or increasing the friction of push rod contact surface; increasing the braking force can also improve the reliability of brake compensation mechanism, but when the braking force comes over a critical value, the effect of braking force on the reliability of the brake is very small. The braking test verifies the effectiveness of the simulation results.

Analyzing the influence of compensation mechanism on braking reliability in the braking process is of great practical significance for improving the braking efficiency and process safety of wind turbine brake.

Sliding wear is a common phenomenon in the iron ore handling industry. Large-scale handling of iron ore bulk-solids causes a high amount of volume loss from the surfaces of bulk-solids-handling equipment. Predicting the sliding wear volume from equipment surfaces is beneficial for efficient maintenance of worn equipment. Recently, the discrete element method (DEM) simulations have been utilised to predict the wear by bulk-solids. However, the sensitivity of wear prediction subjected to DEM parameters has not been systemically investigated at single particle level. To ensure the wear predictions by DEM are accurate and stable, this study aims to conduct the sensitivity analysis at the single particle level.

In this research, pin-on-disc wear tests are modelled to predict the sliding wear by individual iron ore particles. The Hertz–Mindlin (no slip) contact model is implemented to simulate interactions between particle (pin) and geometry (disc). To quantify the wear from geometry surface, a sliding wear equation derived from Archard’s wear model is adopted in the DEM simulations. The accuracy of the pin-on-disc wear test simulation is assessed by comparing the predicted wear volume with that of the theoretical calculation. The stability is evaluated by repetitive tests of a reference case. At the steady-state wear, the sensitivity analysis is done by predicting sliding wear volumes using the parameter values determined by iron ore-handling conditions. This research is carried out using the software EDEM^® 2.7.1.

Numerical errors occur when a particle passes a joint side of geometry meshes. However, this influence is negligible compared to total wear volume of a wear revolution. A reference case study demonstrates that accurate and stable results of sliding wear volume can be achieved. For the sliding wear at steady state, increasing particle density or radius causes more wear, whereas, by contrast, particle Poisson’s ratio, particle shear modulus, geometry mesh size, rotating speed, coefficient of restitution and time step have no impact on wear volume. As expected, increasing indentation force results in a proportional increase. For maintaining wear characteristic and reducing simulation time, the geometry mesh size is recommended. To further reduce simulation time, it is inappropriate using lower particle shear modulus. However, the maximum time step can be increased to 187% T_R without compromising simulation accuracy.

The applied coefficient of sliding wear is determined based on theoretical and experimental studies of a spherical head of iron ore particle. To predict realistic volume loss in the iron ore-handling industry, this coefficient should be experimentally determined by taking into account the non-spherical shapes of iron ore particles.

The effects of DEM parameters on sliding wear are revealed, enabling the selections of adequate values to predict sliding wear in the iron ore-handling industry.

The accuracy and stability to predict sliding wear by using EDEM^® 2.7.1 are verified. Besides, this research accelerates the calibration of sliding wear prediction by DEM.