Abstract
This paper introduces two simplified equations, "Nori formulae," for calculating maximum allowable stress (MAS) in mechanical design engineering. These formulae eliminate the need for traditional safety margins or factors of safety along with factored values across applications ranging from safety pins to spacecraft components. The first formula determines the maximum allowable stress in tension, while the second addresses the maximum allowable stress in shear. The Nori formulae were developed by incorporating fundamental mechanical properties of steel: ultimate tensile strength, yield strength, elongation, and reduction of area—all commonly derived from engineering stress-strain curves in standard tensile testing. This approach effectively utilizes existing global databases of elongation and reduction of area measurements, requiring no additional data generation that would otherwise demand significant time and financial investment. This work addresses a critical gap in the field, as various international design codes and standards currently employ inconsistent design philosophies and safety margins when determining the maximum allowable stress for steel materials.
