Current version: v.3180rc7
CABARET – Ball Bearing Analysis Software
CABARET v.3
CABARET is a bearing analysis code which is applicable to analysis of ball bearings operating at all speeds under general loading. Its use permits design and selection of ball bearings, materials and lubricants as well as prediction of bearing performance for a range of applications from low-speed mechanisms to high-speed turbopumps (the application for which it was originally develop).
CABARET was originally developed by ESTL, part of ESR Technology, under ESA contract no 8280/89/NL/FG and has since been maintained and extended under various ESA contracts, most recently 4000134269/21/NL/MG. Under the terms of these contracts, companies or institutions within ESA member states are entitled to a free-of-charge sub-licence for use of Version 3. In accordance with the terms of the ESA sub-licence, use of the software is limited to its application for peaceful purposes within the field of space research and technology. CABARET can also be licensed by organisations outside the ESA member states, and for other applications.
CABARET integrates analyses for a number of features important in ball-bearing performance in a single code.
CABARET has been originally developed for bearing analysis tailored to the environment of a cryogenic rocket engine turbopump. This application is characterised by high bearing rotational speed, and heavy bearing loads, together with lubrication by thin solid films and cooling by the flow of liquid cryogen through the bearings.
CABARET v.3 retains in full the turbopump specific features, but now also permits a more generalised application of the same bearing analysis tools, by extending its applicability.
User Interface
CABARET v3 aims for ease-of-use, with a modern GUI and a 2D graphical representation of the bearing assembly. As a Matlab Standalone Application, it produces results compatible with Matlab for further analysis, however it does not require a Matlab license to operate.
Quasi-Static Analysis
The basis of CABARET is the so-called “quasistatic analysis” of bearing internal loads and motions. This enables the prediction of stiffness (or deflection) and contract stresses within single bearings or bearing pairs under generalised loading.
Coulombic Torque
This is the load-dependent torque primarily applicable to solid-lubricated ball bearings, but also relevant in liquid lubricated bearings under low speed conditions where viscous losses are negligible.
Fluid traction
For fluid-lubricated bearings, CABARET performs calculations of rolling and sliding resistance of the fluid at the contacts, allowing to extend torque calculations in to the mixed and EHL regimes. It also provides bearing-level torque estimations using the Palmgren-Harris and SKF empirical models.
Fluid Power Losses
For bearings immersed in fluid (e.g. LOX or LH2 in turbopump bearings), CABARET has the ability to estimate the fluid power losses based on empirical equations.
Flash Temperature
The localised “flash temperatures” generated at asperity contacts due to both microslip and skidding can also be estimated.
Thermal and Centrifugal Strain Effects
These modify bearing/shaft or housing fits and so the effective bearing preload. CABARET can predict both these changes and the resulting bearing torque.
Sensitivity Analysis
One of the most useful features of CABARET is the ability to carry out a sensitivity analysis. This feature allows designers to quickly generate curves which show the sensitivity of predicted output values to single input parameters (e.g. to predict the effects of variation of bearing conformity number on torque or deflection).
Libraries
CABARET v.3 includes libraries for Material and Fluid Properties, the latter extended with pressure- and temperature-dependent rheological properties. It also includes a new bearing library, which allows quick introduction of bearing manufacturer data into CABARET assemblies.
Cage Motion
CABARET has a 3 degree of freedom cage motion simulation which enables qualitative assessment cage stability and indication of cage-ball and cage-land collision forces, in both solid- and fluid-lubricated bearings.
Fatigue Life
CABARET can estimate the fatigue life of bearings based on both the classical Lundberg-Palmgren method and the more recent SKF model which incorporates the effects of material properties and the sub-surface contact stress distribution.
Vibration Analysis
CABARET has a basic vibration analysis capability, which predicts the vibration frequency and forces generated by lobing of inner or outer races, together with the effects of variable compliance vibration.
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Getting access to CABARET
To obtain access under and ESA sub-licence for space applications and if your company or institution is in an ESA member state and Canada, please fill in and sign the following form and send it to Dr Achilleas Vortselas: achilleas.vortselas@esrtechnology.com
For any other queries, please contact Mr Simon Lewis.