The correct materials selection in the design of aerospace structures reduces the weight and increases structural efficiency. Since the rotor in gas turbine engines has a significant weight, it is important to reduce its weight. The Rotating disks in these rotors are subjected to mechanical and thermal loads and experience high-temperature gradients and angular velocities. This work aims to analyze the stress of a Rotating disk made of carbon-carbon (C/C) composite to withstand mechanical and thermal loads and reduce the weight of the rotor. The behavior of constant thickness C/C composite disks is studied based on the Tsai-Wu Failure Theory. To do so, first, the basic properties of the material, disk size, rotation speed, temperature distribution, and other requirements are determined. The differential governing equations are obtained by assuming the plane stress state, Hooke's law, and compatibility condition, and the stresses, strains, and displacements are obtained. Considering the safety factors of 1 and 1.5, the critical velocities are calculated using the Tsai-Wu failure theory. Finally, according to the information obtained from the analysis, the evaluation of disks with different layers is compared with other similar disks made with different materials.

In this paper, thermoelastic stress analysis of a laminated composite Rotating disk has been studied using analytical and finite element methods. The governing equations of motion for a composite Rotating disk are derived based on circular disk theory of plates in conjuncture with the minimum potential energy principle. The governed equations of motions are solved analytically using Differential Quadrature Method (DQM). Moreover, for the numerical simulations in FEM, ABAQUS software is used. Two models are considered in the numerical simulations for laminated solid and annular disks as, a) a disk with only one layer in longitudinal direction and layer wise in radial direction, b) a layer wise disk in both longitudinal and radial directions, respectively. After convergence study of the solutions, the results for stress distribution in radial and circumferential directions are obtained and then compared.

In this paper energy method is used to calculate rotor response with loose Rotating disk on it. System equation of motion is obtained based on energy method and Lagrange equation. Mathematical modeling of loose disk in a rotor bearing system has resulted in terms similar to unbalance and gyroscopic effect in the system equation of motion. The effect of loose disk axial position and orthotropic bearing has been considered in this investigation. By assuming that shaft and loose disk are always in contact, the results of these study shows that clearance between loose disk and shaft, shaft speed, mass and mass moment of inertia of disk have a major effect on a rotor response and beating phenomena.

Vibration analysis of Rotating disks is one of the most important problems in turbomachines. In this study, a new method has been presented which analyzed the radial vibration of a turbo-pump Rotating disk carrying two annular concentrated masses located on the disk and at its end. Natural frequencies have been calculated in different Rotating speeds, then results have been compared with each other. The effects of concentrated masses position and intensity on natural frequencies have been investigated. The results show that concentrated masses always have been decreased the value of first natural frequency, but in the case of second and third natural frequencies, depending on the mass concentration magnitude and its position, the magnitude of natural frequency has been increased or decreased. The vibration of the Rotating disk without considering the concentrated mass, was examined. Then the resulting solution was generalized for two connected disks in internal concentrated mass location. The effect of concentrated masses, one on the disk body and the other on the outside of the disk, is considered as boundary conditions in the two disk Equations. The results show that increasing in angular velocity of Rotating disk reduces the natural frequency. Concentrated masses always reduce the first natural frequency. At the second and third natural frequencies, concentrated masses may increase or decrease the natural frequency, which depends on the value and position of concentrated mass. Concentrated mass has the most impact when it is in a position that has the most radial displacement.

This article presents an exact solution for an axisymmetric functionally graded piezoelectric (FGP) Rotating disk with constant thickness subjected to an electric field and thermal gradient. All mechanical, thermal and piezoelectric properties except for Poisson's ratio are taken in the form of power functions in radial direction. After solving the heat transfer equation, first a symmetric distribution of temperature is produced. The gradient of displacement in axial direction is then obtained by assuming stress equation in axial direction to be zero. The electric potential gradient is attained by charge and electric displacement equations. Substituting these terms in the equations for the dimensionless stresses in the radial and circumferential directions yield these stresses and using them in the mechanical equilibrium equation a nonhomogeneous second order differential equation is produced that by solving it, the dimensionless displacement in radial direction can be achieved. The study results for a FGP Rotating hollow disk are presented graphically in the form of distributions for displacement, stresses and electrical potential.

The analysis of the bending behavior of Rotating porous disks with exponential thickness variation consisting of viscoelastic functionally graded material is illustrated. The study of bending in the porous disk was done using the first-order shear deformation theory. The porous disk is under the effect of a combination of mechanical stresses and thermal distribution. All material factors for the porous disk change across the thickness as a power law of radius. To solve the mathematical structure by using the semi-analytical technique for displacements in the porous disk, and then to treat the structure model with viscoelastic material by the correspondence principle and Illyushin’s approximation manner. Numerical outcomes including the effect of porosity parameter, inhomogeneity factor, and relaxation time are presented with three different sets of boundary conditions for the solid and hollow disks. A comparison between porous and perfect disk with numerous values of porosity parameters and different inhomogeneity factors have been shown to emphasize the importance of complex mathematical structure in modern engineering mechanical designs.

Due to the crisis of water shortage, the importance of wastewater treatment and the reuse of wastewater, today, the application of advanced methods of wastewater treatment has been considered. Therefore, in the present study, a Rotating bio-disk system has been used to treat municipal wastewater. To conduct the research, a laboratory-scale reactor unit made of Plexiglas with 35 discs was used, and initially the system used a 20-liter tank in a completely anaerobic manner to increase the reactor efficiency. The aerobic sludge of the wastewater treatment plant of the slaughterhouse has been used for the initial inoculation of the reactor and sugar, urea and potash fertilizer have been used to feed the reactor. The study lasted 96 days in three periods. During the study, the COD level increased from 575 mg/l.d to 1250 mg/l.d. The reactor temperature is in the mesophilic and psychrophilic temperature range for two periods. The results showed that the thickness of the biofilm on the surface of the disks is 2 mm and the pH changes are in the range of 9 to 7. COD removal efficiency during the second period is between 19.13-48% and during the third period is between 50-92%. During the study of the hydraulic retention time factor and the change in the rotation speed of the disk, the highest efficiency was obtained at 93% in 24 hours and 92% at 12 rpm, respectively. Experiment with real wastewater has an efficiency of 80%, which is 12% different from the efficiency of laboratory wastewater.

This paper is dealing with the Elastoplastic analysis of Rotating disks of variable thickness made of functionally graded materials based on Tresca's yield criterion. To do so, the governing equations of Rotating annular disks are established based on the elasticity theory. Then, using Tresca's yield criterion and the elastic-perfectly plastic flow law, the displacement equations and stresses are obtained in the plastic region. In order to find the effects of the shape of the disk profile on its stress distribution, the thickness of the disk cross-section is supposed to vary as an exponential function of the radius. In addition, considering different places at which the yielding starts, the process of expanding the plastic flow is investigated. The obtained results are validated against those reported for homogeneous as well as constant thickness FGM disks, showing good agreement. The findings also demonstrate that taking the variable thickness for the disk cross-section into account has a significant effect on the stress distribution and prediction of the place where the yielding initiate.

The three-dimensional problem of steady fluid deposition on an inclined Rotating disk is illustrated in this study. The governing non-linear partial differential equations are reduced to the nonlinear ordinary differential equations system by similarity transform. The analytical solution applied to solve this system is the Homotopy Perturbation Method (HPM). The velocity and temperature profiles are shown and the influence of Prandtl number and rotation ratio on the flow field and the Nusselt number are discussed in detail. The validity of our solutions is verified by the numerical results.