The Effect of Stiffening on the Stress Concentration in a Flat Plate With a Hole

This research was on the effectiveness of stiffeners fastened on either side of a hole or cutout in a flat plate loaded in tension for reducing stress concentrations at the edge of the cutout. Stress data has been compiled from sixteen flat plate geometries having various hole diameter-to-plate width ratios. Each plate was modeled using an analysis software package and solved without stiffening, and then with stiffeners located at various distances from the hole. The reduction in the maximum stress in each plate geometry for stiffening at various distances from the hole was consistent. The stiffener positions closest to the hole always provided the greatest stiffening. The stress concentration in the plates was reduced 24%–41%. The largest reduction occurred in the plate with the largest hole diameter-to-plate width ratio. As the stiffeners moved farther from the hole, these reductions in the plate maximum stress dropped to as little as 11%. The number and location of the fasteners made a difference in the effectiveness of the stiffeners. Fasteners closest to the cutout were most instrumental in reducing the stress when the stiffeners were close to the hole.