The Importance of 3D scanned mesh processing in FEM simulation results

There are many times when working with mesh elements is unavoidable, and what is more, necessary to obtain a reliable geometry. One of the most common situations of mesh working is reverse engineering, especially if the parts are composed of complex surfaces. When this happens, the reproduction of the product is not an easy task. In those scenarios, it is useful to follow a solid methodology in order to generate the most accurate model from 3D scanned meshes. In this paper, the main differences between the use of parametric models (CAD models) and scanned 3D meshes are discussed. For the parametric design, a complete footwear sole made in Rhinoceros was used. The sole was divided in two well differentiated parts: an outer part made in Nitrile Butadiene Rubber (NBR), and an inner part made in Expanded Polyurethane (E-PUR). The 3D scanned model was obtained with a structured light scanner from the complete sole once it was manufactured. The final scanned model was exported from IDEA software after combining 19 scans, and then modified with Geomagic to separate both parts (outer and inner parts). Both meshes (from parametric models and scanned 3D) were imported in a Finite Element Analysis (FEA) software in order to compare their mechanical behavior. In this case, the FEA was used for determining the stress levels into the complete footwear sole during a slip test in both meshes. Stress results showed no significant differences between the two FEA for the same load values. It can be confirmed therefore, that, the use of a 3D scanned model instead of the original CAD is not a cause of significant error if mesh geometry has a minimum quality.