Finite element analysis of stress concentration singularities in orthotropic/isotropic hole plates on an aircraft wing

The cutouts in the ribs of aircraft wings create stress concentrations. Stress concentrations in an elastic body are very important in structural design and are mainly caused by two mechanisms: the concentration of force acting on a body and geometric discontinuities in the object, such as holes or sudden changes in the geometry of the object's surface. To obtain equivalent stresses and strains for a wing rib without a cutout and with a circular cutout, we considered a perforated plate as the test piece. We studied the stress concentration factor (SCF), around a circular central hole in isotropic and orthotropic rectangular plates subjected to tensile loading using the finite element model, and validated it by comparing the constitutive analytical equations of Heywood and Howland for orthotropic and infinite isotropic plates and with the Matlab program. Next, we analyzed the overall and net stress concentration factor around the hole as a function of different variables: the plate diameter-width ratio (d/W), the effect of the fiber orientation angle (θ°),and the effect of the length/width ratio (L/W). Abaqus was used as design software to extract stress concentration factors for materials such as Al 2024-T3, Glass/Epoxy, and Carbon/Epoxy. These results were then compared with the analytical formula using Matlab as the programming software, the statistics showed that there was good agreement between the stress concentration factor around the hole using Abaqus and the Matlab program formula. It can be concluded that the application of Matlab software for SCF estimation is faster than Abaqus software.