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.

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.

This paper investigates the porosity effect on ROTATING functionally graded piezoelectric (FGP) variable-thickness ANNULAR DISK. Even and uneven porosity distributions for the DISK are approximated. The porous ANNULAR DISK is subjected to the influence of electromagnetic, thermal, and mechanical loadings. Material coefficients are graded and described as a power law in the radial direction of the ANNULAR ROTATING DISK. The resulting differential equation with boundary conditions is solved using the semi-analytical technique. Two cases are studied for the porous ANNULAR DISK, circular DISK, and mounted DISK. The effectiveness of the porosity factor and grading index on the temperature, stresses, and displacement are reported. Comparisons between non-porous and porous ANNULAR DISKs for even and uneven porosity are executed and discussed. The obtained results are presented to conclude the important role of porosity on the ROTATING variable-thickness ANNULAR DISK for the purpose of engineering mechanical design.

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.

This paper deals with the analysis of temperature, deflection and thermal stresses of a multilayered ANNULAR DISK. The thermomechanical properties of the DISK are taken to be temperature dependent. Using Kirchhoff’, s variable transformation, the nonlinear heat conduction equation is reduced to a linear form. Finite integral transform, Fourier series and Fourier transform techniques are used to solve the heat conduction equation and the desired solution is obtained in series form. Deflection, thermally induced resultant moments and the corresponding thermal stresses are determined. Numerical analysis is carried out for a three layered ANNULAR DISK and the results are depicted graphically. Thermosensitivity plays a vital role in the thermal profile of the multilayered DISK. In the temperature dependent case, the radial stress suddenly becomes compressive in the middle region, whereas it is tensile throughout all the regions in the temperature independent case. Due to the inhomogeneous thermal conductivity considered in the form of exponential function, the temperature and the corresponding thermoelastic quantities shows the lag along radial direction.

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 present study deals with the elastic analysis of concave thickness ROTATING DISKs made of functionally graded materials (FGMs).The analysis is carried out using element based gradation of material properties in radial direction over the discretized domain. The resulting deformation and stresses are evaluated for free-free boundary condition and the effect of grading index on the deformation and stresses is investigated and presented. The results obtained show that there is a significant reduction of stresses in FGM DISKs as compared to homogeneous DISKs and the DISKs modeled by power law FGM have better strength.

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.

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.