The roll cage is a key passive safety element in rally vehicles, as it must preserve the crew’s survival space during frontal, lateral, and roof-loading scenarios while significantly influencing the vehicle’s mass and structural stiffness. This study presents a comparative analysis of three materials: structural steel E355, high-strength steel 25CrMo4, and aluminium alloy 7075 T6. A numerical roll cage model was developed in ANSYS using shell elements, parametrically defined tube thicknesses, and load cases representing frontal impact, side impact, and rollover. The results show that steels E355 and 25CrMo4 maintain deformations below allowable limits in frontal loading and rollover, whereas aluminium fails under frontal and lateral loading. Steel 25CrMo4 demonstrates the highest stiffness, lowest deformation, and greatest safety margin, while aluminium, despite its low mass, does not meet safety requirements. The parametric analysis confirms a linear relationship between tube thickness, mass, and deformation, identifying 25CrMo4 as the optimal material for further structural optimization.
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