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SKF BEAST simulates the behavior of a complete bearing, including cages, using a fully 3D, specialized tribological contact model (which also accounts for the effects of small-scale geometric variations, such as surface roughness). SKF BEAST places special focus on the dynamic behavior of all bearing components and their individual contacts. This allows for studies of a bearing’s internal motions and forces under any loading condition.

Many commercial simulation tools offer a simplified bearing model represented by stiffness matrices (or even disregard the bearing completely). With an advanced bearing model, users can account for the non-linear stiffness behavior that can influence the design of other critical design parameters, such as shaft misalignment and gear mesh accuracy.

The SKF simulation programs can build upon or otherwise augment commercial CAD/FEA/CFD systems, enabling importing and exporting of system information that may help provide an accurate description of the bearing dynamics.

SKF BEAST further utilizes fully transient models, compensating for flexibility in bearing geometry, and accommodating all bearing types to develop accurate and detailed bearing models.

Principal output data from SKF BEAST relates to the movements of all bearing components, the contact forces between the components, and the force interaction with the environment. Detailed data from the contacts of all components are produced.

The output data can be studied in several ways. Animation of bearing components can serve as a good visual starting point. Force or velocity vectors can be added to the animation. Some parameters, such as contact pressure, can be displayed as 3D images on the bodies or on parametric surfaces. Output data can be reviewed using graphical formats.

Integrating design for six-sigma

Engineers who are involved in simulation constantly confront the challenges of building an accurate and valid model, as well as determining the specific inputs that should be used, how many and what runs should be made, and what the outputs really mean. The integration of Design for Six Sigma (DfSS) into the modeling process will introduce a framework for optimized evaluation of selected bearing arrangements and contribute to a structured approach to identify critical-to-performance operating parameters.

Moving forward, the combination of virtual simulation and DfSS can generate a virtual design of experiments (DoE). The DoE methodology opens the door to an organized set of simulation runs clearly linked to specific parameters. Through a statistical analysis of DoE results, the robustness of a bearing system can be ascertained along with the influences that design parameters exert on performance.

In a DoE, different calculation runs will be made to rank the parameters in terms of their influence on the bearing’s performance. The model allows more parameters to be analyzed independently, compared with physical assembly and testing. This analysis can help optimize system settings to increase robustness and reduce performance variability.

In the near future, advances in computers and simulation technology can be expected to increase capabilities and provide OEMs with even keener insights into how off-highway vehicle systems can and should perform.

While virtual simulation and testing cannot necessarily replace all physical testing and prototyping, VPD technologies offer a practical methodology to investigate parameters and test conditions too difficult to achieve otherwise. Along the way, the number of iterations on the road to a viable design can be reduced significantly and equipment performance can travel on a smoother path.

Greg Zimmerman is manager of Platform Integration & Engineering Consultancy Services at SKF USA Inc.