The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform

Dirk Bartel - One of the best experts on this subject based on the ideXlab platform.

  • transient thermal elastohydrodynamic simulation of a spiral bevel gear pair with an octoidal tooth profile under Mixed Friction conditions
    Tribology International, 2020
    Co-Authors: Lars Bobach, Ronny Beilicke, Dirk Bartel
    Abstract:

    Abstract A simulation model for the transient thermal elastohydrodynamic calculation of spiral bevel gears with octoidal toothing is presented. The three-dimensional contact geometry is derived directly from the precise geometrical definition of the tooth flank profiles. The tooth trace can be represented both as circular arc and as extended epicycloid. The simulation model is based on the numerical solution of the generalized Reynolds equation and includes models for mass conserving cavitation, non-Newtonian flow, Mixed Friction and microhydrodynamics. For the temperature calculation the energy equation for the fluid and the Fourier heat equation for the solid bodies are solved. Using the example of a spiral bevel gear pair with an extended epicycloid, the capability of the presented simulation model is shown.

  • Validation of a thermal elastohydrodynamic multibody dynamics model of the slipper pad by Friction force measurement in the axial piston pump
    Tribology International, 2017
    Co-Authors: Sohil Hashemi, Lars Bobach, Hendrik Friedrich, Dirk Bartel
    Abstract:

    Abstract The Friction force between one slipper pad and swash plate is measured from a newly developed axial piston pump. This developed pump has common axial piston pump kinematics and loads acting on slipper pad. The pump allows the measurement of the Friction force on the swash plate applied by one slipper pad only and the pressure in the piston chamber. The measurement results, taken from several test rig trails are presented and discussed here. The experiments are simulated by a thermal elastohydrodynamic multibody dynamics model of the slipper pad and swash plate considering mass conserving cavitation, non-Newtonian flow and a Mixed Friction model based on real-measured surface topologies. The simulated Friction forces show a good agreement with the measurements.

  • Simulating transient wear characteristics of journal bearings subjected to Mixed Friction
    Proceedings of the Institution of Mechanical Engineers Part J: Journal of Engineering Tribology, 2012
    Co-Authors: Dirk Bartel, Lars Bobach, T. Illner, L. Deters
    Abstract:

    This article describes a calculation model for the simulation of the transient wear characteristics of journal bearings subjected to Mixed Friction. For predetermined time steps the local wear is calculated for circumference and width. The resulting changes to the gap geometry then flow directly into the further calculation process. The solid contact load ratio and boundary Friction ratio in the Mixed Friction area are calculated on the basis of real rough surfaces. Modifications to the rough surfaces resulting from the running-in process are taken into consideration. In addition the microhydrodynamic effects, elastic deformations of the bearing environment and mass conserving cavitation are also recorded. The calculation model’s potential is demonstrated by means of an unsteady loaded conrod bearing.

  • Thermal elastohydrodynamic simulation of involute spur gears incorporating Mixed Friction
    Tribology International, 2012
    Co-Authors: Lars Bobach, Ronny Beilicke, Dirk Bartel, L. Deters
    Abstract:

    Abstract A model for calculating transient, three-dimensional, thermal elastohydrodynamic tooth flank contacts in spur gears with involute gearing is presented. The calculation model is based on the combined numerical solutions of the generalized Reynolds, energy and Fourier heat equations. Mass conserving cavitation, non-Newtonian flow and the real involute characteristics of the tooth flanks are incorporated. States of Mixed Friction and microhydrodynamic effects are ascertained integrally based on real-measured surface topographies. Straight spur gear pairs serve as an example to present the results of calculating the influence of surface roughness asperities and gearing geometry.

Lars Bobach - One of the best experts on this subject based on the ideXlab platform.

  • transient thermal elastohydrodynamic simulation of a spiral bevel gear pair with an octoidal tooth profile under Mixed Friction conditions
    Tribology International, 2020
    Co-Authors: Lars Bobach, Ronny Beilicke, Dirk Bartel
    Abstract:

    Abstract A simulation model for the transient thermal elastohydrodynamic calculation of spiral bevel gears with octoidal toothing is presented. The three-dimensional contact geometry is derived directly from the precise geometrical definition of the tooth flank profiles. The tooth trace can be represented both as circular arc and as extended epicycloid. The simulation model is based on the numerical solution of the generalized Reynolds equation and includes models for mass conserving cavitation, non-Newtonian flow, Mixed Friction and microhydrodynamics. For the temperature calculation the energy equation for the fluid and the Fourier heat equation for the solid bodies are solved. Using the example of a spiral bevel gear pair with an extended epicycloid, the capability of the presented simulation model is shown.

  • Validation of a thermal elastohydrodynamic multibody dynamics model of the slipper pad by Friction force measurement in the axial piston pump
    Tribology International, 2017
    Co-Authors: Sohil Hashemi, Lars Bobach, Hendrik Friedrich, Dirk Bartel
    Abstract:

    Abstract The Friction force between one slipper pad and swash plate is measured from a newly developed axial piston pump. This developed pump has common axial piston pump kinematics and loads acting on slipper pad. The pump allows the measurement of the Friction force on the swash plate applied by one slipper pad only and the pressure in the piston chamber. The measurement results, taken from several test rig trails are presented and discussed here. The experiments are simulated by a thermal elastohydrodynamic multibody dynamics model of the slipper pad and swash plate considering mass conserving cavitation, non-Newtonian flow and a Mixed Friction model based on real-measured surface topologies. The simulated Friction forces show a good agreement with the measurements.

  • Simulating transient wear characteristics of journal bearings subjected to Mixed Friction
    Proceedings of the Institution of Mechanical Engineers Part J: Journal of Engineering Tribology, 2012
    Co-Authors: Dirk Bartel, Lars Bobach, T. Illner, L. Deters
    Abstract:

    This article describes a calculation model for the simulation of the transient wear characteristics of journal bearings subjected to Mixed Friction. For predetermined time steps the local wear is calculated for circumference and width. The resulting changes to the gap geometry then flow directly into the further calculation process. The solid contact load ratio and boundary Friction ratio in the Mixed Friction area are calculated on the basis of real rough surfaces. Modifications to the rough surfaces resulting from the running-in process are taken into consideration. In addition the microhydrodynamic effects, elastic deformations of the bearing environment and mass conserving cavitation are also recorded. The calculation model’s potential is demonstrated by means of an unsteady loaded conrod bearing.

  • Thermal elastohydrodynamic simulation of involute spur gears incorporating Mixed Friction
    Tribology International, 2012
    Co-Authors: Lars Bobach, Ronny Beilicke, Dirk Bartel, L. Deters
    Abstract:

    Abstract A model for calculating transient, three-dimensional, thermal elastohydrodynamic tooth flank contacts in spur gears with involute gearing is presented. The calculation model is based on the combined numerical solutions of the generalized Reynolds, energy and Fourier heat equations. Mass conserving cavitation, non-Newtonian flow and the real involute characteristics of the tooth flanks are incorporated. States of Mixed Friction and microhydrodynamic effects are ascertained integrally based on real-measured surface topographies. Straight spur gear pairs serve as an example to present the results of calculating the influence of surface roughness asperities and gearing geometry.

Andres Soom - One of the best experts on this subject based on the ideXlab platform.

  • A Two-Component Mixed Friction Model for a Lubricated Line Contact
    Journal of Tribology, 1996
    Co-Authors: Andreas A. Polycarpou, Andres Soom
    Abstract:

    A two-component, two-dimensional Friction model for a lubricated line contact, operating in boundary and Mixed lubrication regimes, is developed. The Friction is explicitly decomposed into the solid and the fluid shear components. The solid component is due to the asperity interactions and the fluid shear arises from the lubricant present at the interface. The Friction model includes the sliding velocity, the instantaneous separation of the sliding bodies, normal to the sliding direction, the normal load and fluid properties. The model is based on unsteady Friction experiments carried out under constant normal loads and time-varying sliding velocities. The model is applied to quasi-steady sliding, unsteady continuous and intermittent sliding, including sticking and momentary reversals of motion. In each case it becomes possible to track the instantaneous fluid shear and solid Friction components.

  • Boundary and Mixed Friction in the Presence of Dynamic Normal Loads: Part I—System Model
    Journal of Tribology, 1995
    Co-Authors: Andreas A. Polycarpou, Andres Soom
    Abstract:

    The instantaneous normal motion between bodies in a sliding contact is an important variable in determining dynamic Friction under unsteady sliding conditions. In order to model Friction under dynamic conditions, it is therefore necessary to combine a dynamic model of the sliding system with an accurate model of thes Friction process. In the present work, the nonlinear normal dynamics of a Friction test apparatus are described by a linearized model at a particular steady loading and sliding condition in a Mixed or boundary-lubricated regime. The geometry is a line contact. The Hertzian bulk contact compliance and film and asperity damping and stiffness characteristics are included as discrete elements. In Part I of the paper , a fifth-order model is developed for the normal dynamics of the system, using both the Eigen-system Realization Algorithm (ERA) and classical experimental modal analysis techniques. In Part II, this system model is combined with a Friction model, developed independently, to describe dynamic Friction forces under both harmonic and impulsive applied normal loads

  • Boundary and Mixed Friction in the Presence of Dynamic Normal Loads: Part II—Friction Transients
    Journal of Tribology, 1995
    Co-Authors: Andreas A. Polycarpou, Andres Soom
    Abstract:

    The normal dynamic model of the sliding system developed in Part I of this paper is combined with a Friction model, obtained separately from the same apparatus, to provide estimates of the Friction under dynamic loading conditions. The two-dimensional Friction model, developed from measurements at constant normal load and slowly varying sliding speeds, includes the normal approach of the sliding bodies as a key variable. From the combined model, estimates of Friction under harmonic loading and of Friction transients associated with short duration impacts are compared with measurements. The very good agreement between estimates and measurements indicates that, while a good Friction model is required, the crucial and most variable aspect of the modeling of dynamic Friction is the representation of the normal dynamics of the sliding system.

  • Two-Dimensional Models of Boundary and Mixed Friction at a Line Contact
    Journal of Tribology, 1995
    Co-Authors: Andreas A. Polycarpou, Andres Soom
    Abstract:

    Two-dimensional dynamic Friction models at a lubricated line contact, operating in boundary and Mixed lubrication regimes, are developed. The Friction coefficient is shown to be a function of the sliding velocity and the instantaneous separation of the sliding bodies, normal to the sliding direction. The models are based on unsteady Friction experiments carried out under constant normal loads and under time-varying sliding velocities. The normal motions at the sliding contact were detected indirectly by contact resistance measurements. The contact resistance is related to the theoretical central film thickness for smooth surfaces. An advanced system identification technique (Minimum Model Error) is implemented to identify the most important terms in a number of nonlinear Friction models. Two Friction models are then nondimensionalized and parameterized. The validity and range of application of the models are then tested, by comparing them with experiments and with selected models proposed by other researchers.

Jinjin Wang - One of the best experts on this subject based on the ideXlab platform.

  • Sliding bifurcation research of an electromechanical coupling drive system containing Friction under external excitation
    International Journal of Applied Electromagnetics and Mechanics, 2016
    Co-Authors: Shuang Liu, Yatao Shi, Jinjin Wang
    Abstract:

    This paper focuses on sliding bifurcation of an electromechanical coupling drive system drived by AC synchronous motor containing Friction under external excitation along with the changes of external excitation frequency. Considering the Mixed Friction on load side, the electromagnetic coupling torque provided by motor side and the external disturbance torque on load side, the dynamical equation of an electromechanical coupling drive system containing Friction under external excitation can be deduced according to Newton’s laws. The stability of periodic solutions in the system is analyzed with Floquet theory. The Filippov convex method is used to extend the system and theoretical conditions of the stick-slip motion are given to numerically predict the sliding bifurcation. The influence of external excitation frequency on the dynamic behavior of drive system is observed and the dynamic behavior of system is verified whether it meets the conditions of sliding bifurcation. Numerical simulations are also given to confirm the results.

  • Sliding bifurcation research of a horizontal–torsional coupled main drive system of rolling mill
    Nonlinear Dynamics, 2015
    Co-Authors: Shuang Liu, Zhao-long Wang, Jinjin Wang
    Abstract:

    Sliding bifurcation of a horizontal–torsional coupled main drive system of rolling mill along with the change of Mixed Friction coefficient under the conditions of autonomy and non-autonomy is studied in this paper. Considering the Friction between the roller and the strip, the torsional vibration of gear pair and the horizontal vibration of the roller, the dynamical equation of a horizontal–torsional coupled main drive system of rolling mill is deduced. The stability of the equilibrium point in the autonomous system is analyzed by using the Hopf bifurcation theorem. The Filippov convex method is used to extend the system. The theoretical conditions of the stick–slip motion are given, which are used to numerically predict the sliding bifurcation. The stability of periodic solutions in the non-autonomous system is analyzed by using the Floquet theory. The influences of Mixed Friction coefficient on the dynamic behaviors of the system under the conditions of autonomy and non-autonomy are compared. Numerical simulations are also given, which confirm the analytical results.

L. Deters - One of the best experts on this subject based on the ideXlab platform.

  • Simulating transient wear characteristics of journal bearings subjected to Mixed Friction
    Proceedings of the Institution of Mechanical Engineers Part J: Journal of Engineering Tribology, 2012
    Co-Authors: Dirk Bartel, Lars Bobach, T. Illner, L. Deters
    Abstract:

    This article describes a calculation model for the simulation of the transient wear characteristics of journal bearings subjected to Mixed Friction. For predetermined time steps the local wear is calculated for circumference and width. The resulting changes to the gap geometry then flow directly into the further calculation process. The solid contact load ratio and boundary Friction ratio in the Mixed Friction area are calculated on the basis of real rough surfaces. Modifications to the rough surfaces resulting from the running-in process are taken into consideration. In addition the microhydrodynamic effects, elastic deformations of the bearing environment and mass conserving cavitation are also recorded. The calculation model’s potential is demonstrated by means of an unsteady loaded conrod bearing.

  • Thermal elastohydrodynamic simulation of involute spur gears incorporating Mixed Friction
    Tribology International, 2012
    Co-Authors: Lars Bobach, Ronny Beilicke, Dirk Bartel, L. Deters
    Abstract:

    Abstract A model for calculating transient, three-dimensional, thermal elastohydrodynamic tooth flank contacts in spur gears with involute gearing is presented. The calculation model is based on the combined numerical solutions of the generalized Reynolds, energy and Fourier heat equations. Mass conserving cavitation, non-Newtonian flow and the real involute characteristics of the tooth flanks are incorporated. States of Mixed Friction and microhydrodynamic effects are ascertained integrally based on real-measured surface topographies. Straight spur gear pairs serve as an example to present the results of calculating the influence of surface roughness asperities and gearing geometry.