Development of a Methodology for Efficient FEM Pre-processes to Aid Simulation-driven Design
Abstract: With both tougher competition and legislations, companies always strive to improve their products while cutting unnecessary costs. This master’s thesis investigates if the after-treatment systems department at the heavy-duty vehicle company Scania CV AB in Södertälje, Sweden can improve their development process by implementing automated FEM pre-processes for welded sheet metal components. The research is based upon theory from various fields within product development, knowledge-based engineering, FEM and design optimization, contributing to an understating of what effects this project could have on the development process as a whole. Large parts of the pre-processes used at the department today were identified as repetitive and suitable for automation. Using a simplified CAD model of an after-treatment system as a case study, a methodology for more efficient FEM pre-processes was developed. The methodology includes changes to the workflow between the design engineer and the CAE engineer as well as a software that automatically meshes welded sheet metal products. First of all, the design engineer inserts lines representing the weld positions in the CAD model and exports the model to the CAE engineer. Hereafter, the CAE engineer simply selects necessary settings for the mesh and launches the developed software that automatically meshes the sheet metal components as well as identifies and meshes the welds. The technique used to mesh the welds in HyperMesh fails for certain weld characteristics, resulting in a robustness of 54 % of the total weld length for the worst case in the case study. These characteristics are welds crossing other welds, welds adjacent to a sharp corner and welds containing a sharp corner. By excluding these problem areas when defining the lines in CATIA, the robustness increases substantially to between 72 % and 88 % of the total weld length in the case study, where the exclusion zones represent 3 % of the total weld length. Based on the case study, the developed methodology could potentially shorten the iterative development process between the design and CAE engineer with a total of 25 %, while the CAE engineer’s tasks in the development process can be cut with up to 60 %. This allows for more time being focused on value-adding tasks, resulting in higher quality products and an increased profit for the company.
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