A comprehensive numerical model for double-layered porous air journal bearing at higher bearing numbers

Kumar, Mandeep; De, S. K.; Samanta, Pranab; Murmu, Naresh Chandra

doi:10.1177/1350650117724054

Cited by 5 publications

(5 citation statements)

References 21 publications

(32 reference statements)

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“…Furthermore, the critical mass parameter values obtained based on nonlinear transient were compared with the values realized using linear perturbation analysis [16]. Figure 11 presents the compassion of the critical mass parameter values for the same operating conditions using both the methods.…”

Section: Effect Of Anisotropymentioning

confidence: 99%

“…It is observed that in-spite of the importance to consider nonzero velocity condition at the vicinity of film and porous region interface, very few studies are reported in the open literature for a hybrid gas journal bearing with double-layered porous bushing. One such study using the velocity slip boundary condition proposed by Beavers-Joseph at porousfilm interface was presented by Kumar et al [16]. Analysis for the steady-state performance characteristics was carried out for a two-layered porous gas journal bearing.…”

Section: Introductionmentioning

confidence: 99%

“…It is also customary to use Newton-Raphson iterative scheme to solve the nonlinear governing equations. However, this method fails to converge at higher bearing number values [16,17]. Hence, it is proposed to use third-order total variation diminishing (TVD) Runge-Kutta scheme to solve the governing equation at porous and film regions.…”

Section: Introductionmentioning

confidence: 99%

“…Comparison of steadystate characteristics of doublelayered porous bearing with the available data from Ref [16]…”

mentioning

confidence: 99%

See 3 more Smart Citations

Nonlinear transient analysis of rigid rotor mounted on externally pressurized double-layered porous gas journal bearings accounting velocity slip

Mallisetty

Samanta

Murmu

2020

J Braz. Soc. Mech. Sci. Eng.

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The present work aims at estimating the journal center trajectories of a rigid rotor mounted on a hybrid, finite gas lubricated journal bearings with double-layered porous bushing using nonlinear transient analysis. To consider velocity slip in the film at the interface between film and porous region, Reynolds equation is modified using the Beavers-Joseph boundary condition. The governing equations of flow at clearance, porous regions are discretized using finite volume method. The variable values at cell-face centers are obtained using interpolation scheme of third order. Those discretized equations coupled with equations of rigid rotor motion are solved by third-order total variation diminishing Runge-Kutta scheme. Influence of velocity slip and design parameters on critical mass parameter values were explored. The observations are presented in the form of graphs that serves as a reference during the design of such bearings.

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Section: Effect Of Anisotropymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Comparison of steadystate characteristics of doublelayered porous bearing with the available data from Ref [16]…”

mentioning

confidence: 99%

See 2 more Smart Citations

Nonlinear transient analysis of rigid rotor mounted on externally pressurized double-layered porous gas journal bearings accounting velocity slip

Mallisetty

Samanta

Murmu

2020

J Braz. Soc. Mech. Sci. Eng.

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show abstract

“…Till date various work have been done on the steady-state aligned or misaligned double-layered porous journal bearings. 7–10…”

Section: Introductionmentioning

confidence: 99%

Non-linear stability analysis of two-layered porous journal bearings with velocity slip and percolation effect of additives of coupled-stress lubricant

Some

Guha

2020

Proceedings of the Institution of Mechanical Engineers, Part J:

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In this paper a non-linear stability analysis of the two-layered porous journal bearing under coupled-stress lubricant has been presented with velocity slip phenomenon and additive’s percolation effect. In this non-linear transient analysis, system stability is determined by tracing the locus of the journal center and various trajectories of journal center locus have been represented in graphical form for different operating conditions. Furthermore, stability characteristics in respect of critical mass parameter and whirl ratio have been studied under various parametric conditions and a comparison between the linear and non-linear stability analysis have been demonstrated. To acquire the non-dimensional pressure values, non-dimensional transient Reynolds equation has been solved and with these pressure values, bearing load carrying capacity are derived. Fourth order Runge-Kutta method is used to solve the second order equations of motion for journal bearing system to obtain the stability characteristics. Results of this analysis may be helpful for designing such bearings.

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Iterative assist-as-needed control with interaction factor for rehabilitation robots

Cao

Cheng

Yang

et al. 2021

Sci. China Technol. Sci.

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Rehabilitation robots for stroke patients have drawn considerable attention because they can reduce the economic and labor costs brought by traditional rehabilitation. Control methods for rehabilitation robots have been developed to stimulate the active motion of patients and to improve the effectiveness of rehabilitation care. However, current control methods can only roughly adjust the system's stiffness and may fail in achieving satisfactory performance. To this end, this paper introduces a novel cost function consisting of the tracking error term and the stiffness term. The cost function contains an interaction factor that represents the patient's motion intention to balance the weight of these two terms. When the patients try to actively do training tasks, the weight of stiffness term increases, which leads to the larger allowable tracking error and lower stiffness eventually. An iterative updating law of the stiffness matrix is given to reduce the proposed cost function. Theoretical analysis based on the Lyapunov theory is given to ensure the feasibility of the proposed algorithm. Furthermore, a force estimation is used to improve interaction control performance. Finally, simulation experiments are provided to show the effectiveness of the proposed algorithm.

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A comprehensive numerical model for double-layered porous air journal bearing at higher bearing numbers

Cited by 5 publications

References 21 publications

Nonlinear transient analysis of rigid rotor mounted on externally pressurized double-layered porous gas journal bearings accounting velocity slip

Nonlinear transient analysis of rigid rotor mounted on externally pressurized double-layered porous gas journal bearings accounting velocity slip

Non-linear stability analysis of two-layered porous journal bearings with velocity slip and percolation effect of additives of coupled-stress lubricant

Iterative assist-as-needed control with interaction factor for rehabilitation robots

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