ESDU 15005 considers the optimisation of the shape of typical holes found in structural components to significantly reduce the peak elastic stresses around the hole@ as well as to increase the fatigue life of the component under a given set of loading and geometry conditions. Finite element analysis (FEA) is used to determine the optimised shapes of single holes in large and finite flat plates under uniaxial and biaxial loading. The optimised holes are shown to have lower peak stresses compared the stresses found around comparable circular holes in flat plate. The effect of reducing the peak stresses by limiting the minimum radius of curvature and by minimising multiple stress peaks around the optimised hole shapes is also discussed. Similarly@ the FEA has been used to find the optimised shapes of two closely-spaced holes under tensile biaxial and mixed biaxial stresses and these are shown to have lower stress concentrations compared to two closely-spaced circular holes. Two examples illustrate the method of modifying the sharp corners commonly found in an optimised hole shape for improved robustness under uniaxial and biaxial loading conditions. ESDU 15005 is closely related to ESDU 15006 which presents stress concentration data for optimised notches and fillets in flat plate.
ESDU 15005-2015 history
2015ESDU 15005-2015 Stress concentration factors for optimised holes in flat plate