Reverse engineering of geometrically complex automotive structures using X-ray-computed tomography and digital image-based finite element methods

摘要

Stress analyses of complex automotive components can be nearly impossible to achieve due to extreme difficulties in generating a realistic finite element model. A digital image-based finite element approach was used to generate a 3-D f element model from computed tomography (CT) scans of two automotive transmission cases. For the first case, original CT slices of 1024×1024×208 provided by ARACOR Inc. (Sunnyvale, CA) were used to generate a 3-D finite element model containing nearly 400,000 8-node brick elements. For the second case, 770×870×759 CT slices were used to generate a 3-D finite element model containing approximately 650,000 3-D elements. The mesh data generation from CT data for both cases took 6 minutes each on an engineering workstation. The resulting finite element meshes were analyzed using a specially designed finite element equation solver. Approximate solution time was 23 hours for the first case and 66 hours for the second case, again on a standard engineering workstation. Von Mises stress results for both cases under a wide open throttle reverse loading condition showed stress concentration in regions that correlated with experimental results. This analysis demonstrates the ability of a digital image-based finite element approach to realistically analyze complicated components. When combined with CT data, the digital image-based FE system can analyze already manufactured parts for comparison with product design data. The maximum total digital FE analysis turnaround time of 3 days including scan time represents a tremendous time savings over traditional finite element meshing techniques which, even if possible, often require an average turnaround time of over 90 days.