Bernhard Schweizer
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Analysis of Air Foil Thrust Bearings under Misalignment Conditions Featuring Performance Limit Curves Open
This paper explores the performance of foil thrust bearings under misalignment conditions, highlighting the need for a fully coupled simulation model to capture their thermo-mechanical behavior. The in-depth multiphysical nonlinear finite …
View article: Passively Enhancing Gas Thrust Bearing Performance Through an Inexpensive and Straightforward Design Optimization of the Rotor Disk
Passively Enhancing Gas Thrust Bearing Performance Through an Inexpensive and Straightforward Design Optimization of the Rotor Disk Open
This article presents an inexpensive passive approach for reducing the thermal bending deformations of rotor disks in gas thrust bearings, featuring an optimized design for the rotor disk. Small geometry changes are incorporated and inerti…
View article: Rigid Air Bearings With 3-Lobe Bore Geometry: Stability and Rotor Dynamics for High-Speed Turbosystems
Rigid Air Bearings With 3-Lobe Bore Geometry: Stability and Rotor Dynamics for High-Speed Turbosystems Open
This paper considers rigid air bearings with a three-lobe bore geometry. They usually exhibit very poor stability characteristics, which make them unsuitable for practical highspeed rotor systems. However, the stability of these bearings m…
View article: Passively Enhancing Gas Thrust Bearing Performance Through an Inexpensive and Straightforward Design Optimization of the Rotor Disk
Passively Enhancing Gas Thrust Bearing Performance Through an Inexpensive and Straightforward Design Optimization of the Rotor Disk Open
This article presents an inexpensive passive approach for reducing the thermal bending deformations of rotor disks in gas thrust bearings, featuring an optimized design for the rotor disk. Small geometry changes are incorporated and inerti…
View article: Compensating thermal bending of the runner disk in hydrodynamic thrust bearings: Simple approach for passively improving the performance of gas bearings
Compensating thermal bending of the runner disk in hydrodynamic thrust bearings: Simple approach for passively improving the performance of gas bearings Open
This paper presents a method for passively compensating thermal bending distortions of the thrust disk in gas thrust bearings by passive approaches. Thermal bending displays a prominent problem in hydrodynamic thrust bearings, especially i…
View article: Thermo-elasto-hydrodynamic analysis of bump-type air foil thrust bearings considering misalignment
Thermo-elasto-hydrodynamic analysis of bump-type air foil thrust bearings considering misalignment Open
In this study, a multi-pad bump-type foil thrust bearing with a taper-land height profile is investigated. A detailed thermo-elastohydrodynamic (TEHD) finite element (FE) model is used comprising all bearing pads instead of only a single p…
View article: Numerical and experimental analysis of margin geometries of twist drills in deep hole machining operations
Numerical and experimental analysis of margin geometries of twist drills in deep hole machining operations Open
In deep hole machining operations with twist drills, whirling vibrations lead to a significant increase in hole diameter deviation and circularity error. In this article, a nonlinear physical model with special consideration of the contact…
View article: Numerical investigations on high-speed turbo-compressor rotor systems with air ring bearings: Nonlinear vibration behavior and optimization
Numerical investigations on high-speed turbo-compressor rotor systems with air ring bearings: Nonlinear vibration behavior and optimization Open
Regarding aerodynamic bearings, mainly two basic types can be distinguished: air bearings with a rigid housing and air foil bearings with an elastic supporting structure. Here, a modified bearing concept -- called air ring bearing -- is in…
View article: Co-simulation with variable approximation order: order control algorithm for solver coupling approaches
Co-simulation with variable approximation order: order control algorithm for solver coupling approaches Open
Considering co-simulation and solver coupling approaches, the coupling variables have to be approximated within a macro-time step (communication-time step), e.g., by using extrapolation/interpolation polynomials. Usually, the approximation…
View article: Numerical Analysis of Fluid‐Film‐Cavitation on Rotordynamic Vibration and Stability Behavior
Numerical Analysis of Fluid‐Film‐Cavitation on Rotordynamic Vibration and Stability Behavior Open
The dynamic vibration and stability behavior of a rotor supported in journal bearings is investigated. In the lubricating film of a hydrodynamic bearing, different cavitation phenomena may occur. Cavitation in hydrodynamic bearings is most…
View article: Higher‐Order Index‐1 Co‐Simulation Approach: Solver Coupling for Multibody Systems
Higher‐Order Index‐1 Co‐Simulation Approach: Solver Coupling for Multibody Systems Open
This paper attends to a co‐simulation approach for solver coupling in time domain. A general multibody system is divided into several subsystems, which are coupled by algebraic constraints. The coupling technique analyzed here is a linear‐…
View article: Reduction of Computation Time by Parallelization and Incorporating Co-Simulation Techniques
Reduction of Computation Time by Parallelization and Incorporating Co-Simulation Techniques Open
The co-simulation methods considered here are based on the idea of splitting an overall model into different subsystems; the subsystems are then simulated as a coupled problem. Such an approach can be used advantageously for analyzing comp…
View article: Numerical stability of explicit and implicit co-simulation methods
Numerical stability of explicit and implicit co-simulation methods Open
Within a co-simulation approach, the subsystems are integrated by specific solvers; data exchange is accomplished only at certain user-defined macro-time points. Due to the approximation of the coupling variables by polynomials and as a re…
View article: Transient Run-Up Simulations of Rotors in Journal Bearings Considering Mass-Conserving Cavitation Approaches
Transient Run-Up Simulations of Rotors in Journal Bearings Considering Mass-Conserving Cavitation Approaches Open
The influence of mass-conserving cavitation modeling approaches on the stability of rotors in journal bearings is investigated. The model consists of a rotor represented by a flexible multibody system and the bearings discretized with fini…