General expressions for the stress intensity factor of a one-point bend beam

The aim of this work is to find general expressions to determine the stress intensity factor of a one-point bend beam-like specimen, whether from the measurement of the applied load or the crack mouth opening displacement. The expressions, obtained by applying the superposition principle, involve the decomposition of the general case into three auxiliary problems. The solution of two of them (pure bending and three-point bending) is well known, while the solution of the third (one-point bending) is developed in the present work. The proposed expressions are compared to numerical results obtained by the finite element method and their accuracy is equal to or better than available expressions published elsewhere.