Abstract

Simulation models are laying the fundamentals for understanding system characteristics, predicting real components behaviour and thus design improvements. For this purpose, adequate simulation models have to be developed which are commonly derived from geometry, e.g. CAD, parts. Design studies as sensitivity studies using parametric geometry models can significantly support the building of model and assembly understanding. Knowledge about the influence of specific substructures on the component behaviour is decisive especially in early design phases and besides of interest for model simplifications. The desire for simplifications in order to reduce computational simulation effort is still present even in times of increasing computational resources. However, CAD model structure can differ between application cases and does not inherit a parametric set-up in most of the cases due to the implied significant effort. This in turn depicts an obstacle for previously mentioned design studies of various types. For this reason, the presented work describes an approach to automatically rebuild quasi-axisymmetric geometries in form of a hierarchical feature-based and semi-parametric CAD model. To achieve this goal, silhouette information is used for accessing geometric properties. Methods combine three dimensional information with the approximated two dimensional data. Further algorithms map the cross-section to CAD entities to increase its accuracy. This cross-section in turn supports the segmentation of the geometry model. The resulting segmented substructures and intersections are analysed in detail and grouped using the gathered geometry information. On the basis of this information, the model can be rebuild using common CAD features associated with introduced parameters, serving as digital interface for external accessibility. This semi-parametrized model can serve as starting point for fundamental design sensitivity studies, offer substructure information for FE transfer purposes and can be the basis for an automated full-parametrized geometry approach. With the presented automated approach, the manual effort for building a feature-based model, for implementing major parameter and also for simplifying a geometry is reduced while it paves the way for further opportunities regarding automated product development.