A Comparison of CATIA V5 and ANSYS for the Design and Finite Element Analysis of a Standard Wing Rib for Passenger Aircraft

Abstract

Under flight stress, an aircraft wing's aerodynamic shape shouldn't deform too much, and the skin-stringer panels shouldn't buckle locally under compressive force if the wing is supported at close enough intervals. During normal flight, the wing ribs—which are transverse structural members—meet these requirements by maintaining the aerofoil section, transferring aerodynamic and concentrated loads from the stringers and skin to the spars, and resisting in-plane shear, rib-crushing (Brazier), and Poisson-ratioinduced bending loads. This study details the design, 3D modeling, and finite element stress analysis of a typical passenger aircraft wing rib with lightning holes. It compares the structural performance of three potential rib materials, namely structural steel, aluminum alloy 7075-T6, and a longcarbon-fiber-reinforced epoxy composite, under a standard static load scenario. The three-dimensional rib geometry was created using CATIA V5 Part Design. It is composed of an aerofoil-shaped web with flanged edges, integral stiffening flanges between bays, and six circular lightening holes with graduated diameters. After that, it was imported into ANSYS Workbench, mesh-modified, and analyzed statically for each material candidate using a representative distributed load and fixed-support boundary condition. A peak equivalent (von Mises) stress of 340-354 MPa, concentrated at the sharp reentrant corners between the lightening holes and the stiffening flanges, is observed in all three materials; structural steel has the lowest total deformation (2.65 mm) but the highest mass, aluminum 7075-T6 has an intermediate deformation (7.51 mm) at about 35% of the steel mass, and the carbon-epoxy composite has the highest deformation (9.19 mm) at about 19% of the steel mass. Due to the idealized, unfilleted flange-hole geometry and mesh-density effects at these singular features, the peak stress at these local stress-concentration locations exceeds the quoted yield strength of all three materials. The paper discusses the filletradius and mesh-refinement work that was necessary before any material could be considered structurally qualified for the load case examined. The carbon-epoxy composite provides the highest weight savings, but at the expense of significantly higher deformation—a trade-off that is directly relevant to weight-critical wing-structure design—as compared to the other two materials, aluminum 7075-T6 offers the most balanced stiffness-to-weight trade-off. Keywords - Aircraft Structures, Carbon Fiber Reinforced Polymer, Finite Element Analysis, ANSYS, and CATIA are some of the topics covered.