Development of a fast finite element modelling methodology based on geometric simplification for industrial structural assessment Integration Internship Global Design Technology SA

Abstract

This thesis develops a structured finite element modelling methodology to reduce preprocessing time for industrial structural assessments while maintaining sufficient accuracy. The work addresses a common bottleneck: lengthy geometric preparation and meshing of complex CAD assemblies containing numerous small features.

The methodology combines global and local geometric simplifications guided by load path analysis, not purely geometric criteria. Global simplifications replace negligible bodies or fasteners with lumped masses or equivalent connections. Local simplifications remove small features outside primary load transfer zones while preserving critical features such as internal blends and holes on load paths with dedicated mesh refinement. A thickness based global mesh sizing using quadratic tetrahedral elements is validated through convergence studies on benchmark bending problems.

The methodology is applied to an industrial case study (SNCB air conditioning lift trolley) under two loading configurations. Results are compared against an unsimplified solid model and an industrial shell model. The proposed approach preserves overall deformation modes, load transfer mechanisms and critical zone identification. Local stress differences are limited and attributable to well identified modelling choices. Pre/Post processing time is reduced from approximately 20 hours to 3 hours.

The methodology is well suited for preliminary design phases and global structural assessments where rapid iteration is essential. Limitations include sensitivity of local stress predictions to mesh refinement and lack of experimental validation. Perspectives include semi automated simplification scripts and calibration against experimental data.