The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform

Suraj P. Harsha - One of the best experts on this subject based on the ideXlab platform.

  • The Effect of Surface Waviness and Number of Rolling Elements on the Dynamic Behavior of a Rotor-Bearing System
    Volume 1: 21st Biennial Conference on Mechanical Vibration and Noise Parts A B and C, 2007
    Co-Authors: Suraj P. Harsha, C. Nataraj
    Abstract:

    In the paper, the effects of the number of rolling elements and wave number of Surface Waviness on the nonlinear dynamic analysis of a rotor-bearing system has been studied. In the analytical formulation, the contacts between rolling elements and races are considered as nonlinear springs, whose stiffnesses are obtained by using Hertzian elastic contact deformation theory. The results are presented in the form of Fast Fourier Transformations (FFT) and Poincare maps, which show that the vibration characteristics of the rotor and its bearings change when the bearings operate in different regions of their nonlinear load deflection characteristics. The appearance of regions of periodic, sub-harmonic and chaotic behavior has been observed to be strongly dependent on number of rolling elements.Copyright © 2007 by ASME

  • stability analysis of a rotor bearing system due to Surface Waviness and number of balls
    International Journal of Mechanical Sciences, 2004
    Co-Authors: Suraj P. Harsha, P K Kankar
    Abstract:

    Abstract In the paper, the stability analysis of a rigid rotor supported by ball bearings has been studied. In the analytical formulation, the contacts between balls and races are considered as nonlinear springs, whose stiffnesses are obtained by using Hertzian elastic contact deformation theory. The implicit type numerical integration technique Newmark-β with Newton–Raphson method is used to solve the nonlinear differential equations iteratively. The effects of Surface Waviness and the varying number of balls on stability of rotor bearing system are observed. All results presented in form of fast fourier transformations show that the vibration characteristics of the rotor and its bearings change, when the bearings operate in different regions of their nonlinear load deflection characteristics. From the analysis, it is implied that the number of balls and number of waves in the ball bearing are two important governing parameters affecting its dynamic behavior.

  • Nonlinear Dynamic Response of a Rotor Bearing System Due to Surface Waviness
    Nonlinear Dynamics, 2004
    Co-Authors: Suraj P. Harsha, K. Sandeep, Ravi Prakash
    Abstract:

    In this paper, the radial vibrations of a rigid rotor supported by ball bearings are studied. In the analytical formulation, contacts between the balls and races are considered as nonlinear springs whose stiffnesses are obtained by using Hertzian elastic contact deformation theory. The implicit type numerical integration technique Newmark-β with the Newton-Raphson method is used to solve the nonlinear differential equations iteratively. The effect of bearing running Surface Waviness on the vibrations of rotor is investigated. The formulation predicts discrete spectrum with specific frequency components for each order of Waviness. Numerical results obtained from the simulation are validated with respect to those of prior researchers.

  • Non-linear dynamic behaviors of rolling element bearings due to Surface Waviness
    Journal of Sound and Vibration, 2004
    Co-Authors: Suraj P. Harsha, K. Sandeep, Ravi Prakash
    Abstract:

    Abstract An analytical model to predict non-linear dynamic responses in a rotor bearing system due to Surface Waviness has been developed. In the analytical formulation the contacts between the rolling elements and the races are considered as non-linear springs, whose stiffness are obtained by using Hertzian elastic contact deformation theory. The governing differential equations of motion are obtained by using Lagrange's equations. The implicit type numerical integration technique Newmark-β with Newton–Raphson method is used to solve the non-linear differential equations iteratively. A computer program is developed to simulate Surface Waviness of the components. Results presented in the form of fast Fourier transformation with agreement of various author's experimental researches.

P.h. Shipway - One of the best experts on this subject based on the ideXlab platform.

  • the effect of particle hardness and shape when abrasive water jet milling titanium alloy ti6al4v
    Wear, 2009
    Co-Authors: G Fowler, I. R. Pashby, P.h. Shipway
    Abstract:

    Abstract Legislative restriction on effluent disposal has resulted in an increase in the environmental costs of chemical milling and replacement methods are being sought. Abrasive water jet cutting (AWJ) is a mature process that is employed to through cut materials that are difficult to process by more conventional methods and the process is also being developed for controlled depth milling (CDM) to produce three-dimensional features which in the past might have been produced by chemical or etching processes. A major problem to be solved when using AWJ as a CDM technique is that of tolerance on depth, Surface Waviness and Surface roughness of the milled area. In the current work, the effects of milling parameters on the Surface characteristics are investigated when milling a titanium alloy (Ti6Al4V) with different abrasives, namely white and brown aluminium oxide, garnet, glass beads and steel shot. It has been demonstrated that the ratio between the hardness of the workpiece and the abrasive is more important than particle shape. Material removal rate and Surface roughness increased when particle hardness is increased. Shape factor and particle hardness have no significant effect on Surface Waviness. For the abrasives investigated; traverse speed is shown to govern the operative mechanism of material removal and thus the material removal rate. It is also shown that the Surface Waviness can be reduced as the traverse speed is increased whilst, the Surface roughness is not strongly dependent on traverse speed.

  • abrasive water jet controlled depth milling of ti6al4v alloy an investigation of the role of jet workpiece traverse speed and abrasive grit size on the characteristics of the milled material
    Journal of Materials Processing Technology, 2005
    Co-Authors: G Fowler, P.h. Shipway, I. R. Pashby
    Abstract:

    Abstract Due to difficulties in the use of traditional mechanical methods to mill of difficult-to-machine materials (especially in thin section), methods such as chemical milling or etching have commonly been employed. However, increasing legislative restriction on disposal of effluent has resulted in an increase in the environmental costs of such processes, and has prompted examination of alternative processes for milling to a controlled depth. Abrasive water-jet (AWJ) technology is used in a routine manner in manufacturing industry to cut materials that are difficult to cut by other methods. A similar process, where AWJ is used for controlled depth milling (CDM) is thus considered here. The main problem to be solved in the use of AWJ as a CDM technique is that of tolerance on depth, Surface Waviness and Surface roughness of the milled area. In the current work, the effects of jet–workpiece traverse speed, number of passes of the jet and abrasive grit size on the material removal rate, Surface Waviness and Surface roughness are investigated. Traverse speed is shown to govern the operative mechanism of material removal and thus the material removal rate. It is also shown that the Surface Waviness can be reduced as the traverse speed is increased, but it should be noted that Waviness increases with number of passes of the jet over the workpiece. The Surface roughness is not strongly dependent on traverse speed. Smaller sized grit leads to a reduction in material removal rate but also to a decrease in both Waviness and roughness.

I. R. Pashby - One of the best experts on this subject based on the ideXlab platform.

  • the effect of particle hardness and shape when abrasive water jet milling titanium alloy ti6al4v
    Wear, 2009
    Co-Authors: G Fowler, I. R. Pashby, P.h. Shipway
    Abstract:

    Abstract Legislative restriction on effluent disposal has resulted in an increase in the environmental costs of chemical milling and replacement methods are being sought. Abrasive water jet cutting (AWJ) is a mature process that is employed to through cut materials that are difficult to process by more conventional methods and the process is also being developed for controlled depth milling (CDM) to produce three-dimensional features which in the past might have been produced by chemical or etching processes. A major problem to be solved when using AWJ as a CDM technique is that of tolerance on depth, Surface Waviness and Surface roughness of the milled area. In the current work, the effects of milling parameters on the Surface characteristics are investigated when milling a titanium alloy (Ti6Al4V) with different abrasives, namely white and brown aluminium oxide, garnet, glass beads and steel shot. It has been demonstrated that the ratio between the hardness of the workpiece and the abrasive is more important than particle shape. Material removal rate and Surface roughness increased when particle hardness is increased. Shape factor and particle hardness have no significant effect on Surface Waviness. For the abrasives investigated; traverse speed is shown to govern the operative mechanism of material removal and thus the material removal rate. It is also shown that the Surface Waviness can be reduced as the traverse speed is increased whilst, the Surface roughness is not strongly dependent on traverse speed.

  • abrasive water jet controlled depth milling of ti6al4v alloy an investigation of the role of jet workpiece traverse speed and abrasive grit size on the characteristics of the milled material
    Journal of Materials Processing Technology, 2005
    Co-Authors: G Fowler, P.h. Shipway, I. R. Pashby
    Abstract:

    Abstract Due to difficulties in the use of traditional mechanical methods to mill of difficult-to-machine materials (especially in thin section), methods such as chemical milling or etching have commonly been employed. However, increasing legislative restriction on disposal of effluent has resulted in an increase in the environmental costs of such processes, and has prompted examination of alternative processes for milling to a controlled depth. Abrasive water-jet (AWJ) technology is used in a routine manner in manufacturing industry to cut materials that are difficult to cut by other methods. A similar process, where AWJ is used for controlled depth milling (CDM) is thus considered here. The main problem to be solved in the use of AWJ as a CDM technique is that of tolerance on depth, Surface Waviness and Surface roughness of the milled area. In the current work, the effects of jet–workpiece traverse speed, number of passes of the jet and abrasive grit size on the material removal rate, Surface Waviness and Surface roughness are investigated. Traverse speed is shown to govern the operative mechanism of material removal and thus the material removal rate. It is also shown that the Surface Waviness can be reduced as the traverse speed is increased, but it should be noted that Waviness increases with number of passes of the jet over the workpiece. The Surface roughness is not strongly dependent on traverse speed. Smaller sized grit leads to a reduction in material removal rate but also to a decrease in both Waviness and roughness.

G Fowler - One of the best experts on this subject based on the ideXlab platform.

  • the effect of particle hardness and shape when abrasive water jet milling titanium alloy ti6al4v
    Wear, 2009
    Co-Authors: G Fowler, I. R. Pashby, P.h. Shipway
    Abstract:

    Abstract Legislative restriction on effluent disposal has resulted in an increase in the environmental costs of chemical milling and replacement methods are being sought. Abrasive water jet cutting (AWJ) is a mature process that is employed to through cut materials that are difficult to process by more conventional methods and the process is also being developed for controlled depth milling (CDM) to produce three-dimensional features which in the past might have been produced by chemical or etching processes. A major problem to be solved when using AWJ as a CDM technique is that of tolerance on depth, Surface Waviness and Surface roughness of the milled area. In the current work, the effects of milling parameters on the Surface characteristics are investigated when milling a titanium alloy (Ti6Al4V) with different abrasives, namely white and brown aluminium oxide, garnet, glass beads and steel shot. It has been demonstrated that the ratio between the hardness of the workpiece and the abrasive is more important than particle shape. Material removal rate and Surface roughness increased when particle hardness is increased. Shape factor and particle hardness have no significant effect on Surface Waviness. For the abrasives investigated; traverse speed is shown to govern the operative mechanism of material removal and thus the material removal rate. It is also shown that the Surface Waviness can be reduced as the traverse speed is increased whilst, the Surface roughness is not strongly dependent on traverse speed.

  • abrasive water jet controlled depth milling of ti6al4v alloy an investigation of the role of jet workpiece traverse speed and abrasive grit size on the characteristics of the milled material
    Journal of Materials Processing Technology, 2005
    Co-Authors: G Fowler, P.h. Shipway, I. R. Pashby
    Abstract:

    Abstract Due to difficulties in the use of traditional mechanical methods to mill of difficult-to-machine materials (especially in thin section), methods such as chemical milling or etching have commonly been employed. However, increasing legislative restriction on disposal of effluent has resulted in an increase in the environmental costs of such processes, and has prompted examination of alternative processes for milling to a controlled depth. Abrasive water-jet (AWJ) technology is used in a routine manner in manufacturing industry to cut materials that are difficult to cut by other methods. A similar process, where AWJ is used for controlled depth milling (CDM) is thus considered here. The main problem to be solved in the use of AWJ as a CDM technique is that of tolerance on depth, Surface Waviness and Surface roughness of the milled area. In the current work, the effects of jet–workpiece traverse speed, number of passes of the jet and abrasive grit size on the material removal rate, Surface Waviness and Surface roughness are investigated. Traverse speed is shown to govern the operative mechanism of material removal and thus the material removal rate. It is also shown that the Surface Waviness can be reduced as the traverse speed is increased, but it should be noted that Waviness increases with number of passes of the jet over the workpiece. The Surface roughness is not strongly dependent on traverse speed. Smaller sized grit leads to a reduction in material removal rate but also to a decrease in both Waviness and roughness.

Ravi Prakash - One of the best experts on this subject based on the ideXlab platform.

  • Nonlinear Dynamic Response of a Rotor Bearing System Due to Surface Waviness
    Nonlinear Dynamics, 2004
    Co-Authors: Suraj P. Harsha, K. Sandeep, Ravi Prakash
    Abstract:

    In this paper, the radial vibrations of a rigid rotor supported by ball bearings are studied. In the analytical formulation, contacts between the balls and races are considered as nonlinear springs whose stiffnesses are obtained by using Hertzian elastic contact deformation theory. The implicit type numerical integration technique Newmark-β with the Newton-Raphson method is used to solve the nonlinear differential equations iteratively. The effect of bearing running Surface Waviness on the vibrations of rotor is investigated. The formulation predicts discrete spectrum with specific frequency components for each order of Waviness. Numerical results obtained from the simulation are validated with respect to those of prior researchers.

  • Non-linear dynamic behaviors of rolling element bearings due to Surface Waviness
    Journal of Sound and Vibration, 2004
    Co-Authors: Suraj P. Harsha, K. Sandeep, Ravi Prakash
    Abstract:

    Abstract An analytical model to predict non-linear dynamic responses in a rotor bearing system due to Surface Waviness has been developed. In the analytical formulation the contacts between the rolling elements and the races are considered as non-linear springs, whose stiffness are obtained by using Hertzian elastic contact deformation theory. The governing differential equations of motion are obtained by using Lagrange's equations. The implicit type numerical integration technique Newmark-β with Newton–Raphson method is used to solve the non-linear differential equations iteratively. A computer program is developed to simulate Surface Waviness of the components. Results presented in the form of fast Fourier transformation with agreement of various author's experimental researches.