Travail de fin d'études et stage[BR]- Travail de fin d'études : Simulation-based comparative analysis of bolted and welded ladder frame chassis configurations with SOLIDWORKS[BR]- Stage d'insertion professionnelle : Glutton (Andenne, BE)

Abstract

Structural optimization remains a key objective for engineers as industrial performance standards evolve. This thesis evaluates, from a structural perspective, an alternative welded configuration for the ladder frame chassis of the Glutton® Zen® electric street sweeper, comparing it to the current bolted configuration. The comparison is performed using finite element analysis (FEA) with SOLIDWORKS, simulating the two chassis configurations under the most critical loading conditions: bending and torsion. Apreliminary analysis, including a 2D beam approximation and a simplified 3D beam model, identified the suspension mounting points and a region near the center of gravity as high-stress zones. A detailed finite element analysis using shell elements was conducted under both static and dynamic loading scenarios. In static bending, the welded chassis exhibited performance comparable to the bolted chassis, with a 7.14% increase in maximum von Mises stress and only a 1.04% increase in displacement. Under pure torsion, the welded chassis demonstrated superior torsional resistance, supported by modal analysis results showing a 7.6% higher natural torsional frequency for the welded configuration. For dynamic analysis, the load was modelled as the sum of the static load and the suspension-induced load, calculated using a simplified quarter-car model based on a max imum vehicle speed of 25 km/h. The dynamic load was found to be 2.14 times greater than the static load. During dynamic bending, the welded chassis experienced more pro nounced deformations due to its lower mass, while sustaining the same load as the bolted version. In dynamic torsion, the welded chassis exhibited marginally higher deflection but remained within 10% of the bolted chassis’ performance. Anoptimized welded design was proposed, reducing the front axle cross-member thick ness from 8 mm to 4 mm and adding an auxiliary cross member. These modifications achieved a 5 kg (10%) reduction in weight and a 30% increase in front-end torsional stiffness. Overall, this study validates the welded chassis as a structurally viable and lightweight alternative to the bolted configuration.