COBRA™ Software Family

(Computer Optimized Ball and Roller bearing Analysis software)

In close cooperation with our partners RBTS, Inc. (USA) and J.V. Poplawski & Associates (USA) ARLA offers powerful software packages including engineering services concerning rolling element bearing analysis and optimization. Further information are available on request.

COBRA-EHL™

(ElastoHydrodynamic Lubrication)

This entry-level software package is designed for the mechanical designer and engineer. COBRA-EHL analyzes the interaction of up to 6 bearing rows on a rigid shaft under combined Radial, Thrust, and Moment Loading in 3 degrees of freedom. The program has a visual front end that allows the user to interactively change input data and preview results without having to exit the program. Lubricant Film Thickness and associated Life Adjustment Factors are internally computed. COBRA-EHL can analyze both solid and spring preloaded bearings. Misalignment, axial float and hybrid bearings are included. The program includes Radial and Angular Contact ball bearings plus Cylindrical, Tapered and Spherical roller bearings. Bearing and System Classical L10 Fatigue Life is calculated using the ANSI/ISO Standard Rating Method. Timken BRR and Life are computed for Tapered Roller bearings. COBRA-EHL also contains internal geometry estimation based on envelope size of the bearing. The current version also includes full element results output and analysis of crowned rollers using the laminated roller model. COBRA-EHL is available as integrated part "Rolling Element" of the  ARMD™ software.

Limitation: shaft speeds under 1 million DN,
where DN = bearing bore [mm] x shaft speed [rpm].

Example 1
Example 2
Example 3

COBRA-AHS™

(Advanced High Speed)

COBRA-AHS analyzes up to 6 bearing rows on a flexible or rigid shaft loaded in 5 degrees of freedom. Bearing models include high-speed ball, cylindrical roller and tapered roller bearings. Housing and shaft distortion effects due to out-of-round, out-of-flat and local slope at each rolling element are included. Bearing heat generation and cage forces are calculated. Roller edge stress concentration is calculated due to local roller misalignment for crowned rollers and displayed as a 3D color contour plot. Bearing fit-up analysis is performed using classical thick ring press fit theory as well as a seamless interface to ANSYS FEA models of the bearing row that are automatically constructed and analyzed with results returned to COBRA. Shaft and housing sleeves are also included if present. Data I/O is easy via a visual front end and numerous pre-defined results plots. Skid load estimates and duty cycle analysis are included. Individual bearing temperature models are in the process of being completed for estimating inner and outer race operating temperatures using the pre-described ANSYS models. An iterative thermal / dimensional interaction analysis option is also available. A copy of ANSYS-ED is included with the package and used for the automatic fit-up and thermal analysis. COBRA-AHS is available in 3 versions: Baseline, Intermediate and Full.

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