ABSTRACT
Two- and three-dimensional systems of stress and strain are often met in the field of structural analysis. In the case of two-dimensional systems of stress and strain, such cases are often met on the decks and bulkheads of ships, together with those on rudders and propeller blades. Similar cases are met with aircraft and submarine structures, on the fuselages and wings of aircraft, and the pressure hulls and bulkheads of submarines. In these cases, even though strain gauges can be used to measure a two-dimensional system of stress or strain, very often the strain gauges cannot readily determine the maximum or principal stresses and strains, because they lie on angles which may be at a different angle to the measured strains. Two dimensional and principal stresses also occur on boilers, condensers, nuclear reactors, silos, and so on.
