Abstract
The need for rational and reliable design methods to meet the continual demand for higher standards of performance and lower unit costs is the incentive for providing the designer with comprehensive and accurate information on the magnitude of stress concentrations associated with the geometry of a component. Theoretical stress concentration factors are used indirectly for the calculation of strength reduction factors from which the life of components suffering fluctuating loading can be predicted and are also of direct relevance in cases of failure by brittle fracture under conditions of steady loading. Fairly comprehensive and accurate information is available for the simpler loading cases such as torsion, direct load or uniform bending of many basic engineering components but, in practice, bending is generally accompanied by shear and for this condition the existing information is both scanty and unreliable. A comprehensive series of tests using two-dimensional photoelastic methods have been carried out on shouldered plate models covering a wide range of useful parameters and subjected to various loading configurations of bending with shear. By means of a consistent extrapolation procedure based on curve fitting by orthogonal polynomials and the use of other statistical methods it has been demonstrated that boundary Stresses can be described by linear expressions involving two basic factors associated, independently, with the respective effects of bending and shear. Values of the resulting basic factors are presented in the form of curves plotted against the model parameters. For design purposes, methods are examined whereby the basic information can be used, either in the form of empirical expressions from which peak stresses can be calculated for any given set of parameters, or as input data to a digital computer programmed to control an incremental plotter to give, automatically, curves of stress variation for any selected configuration of bending with shear.