The problem of the definition of general yielding in notched bend bars has been addressed using both finite element method (FEM) calculations and also experiments on a variety of steels. Yielding and plastic zone development were found, in agreement with the literature, to be quite different for materials which yield continuously and those which yield discontinuously (i.e. with yield drop, Luders strain, or both). For the former case, the plastic zone is diffuse, broad, and develops slowly, quite unlike the shape of the slipline field at general yield, and without any indications in the load-displacement curve. Values of the constraint factor from the present experiments were compared to those from earlier work and from FEM calculations.

Yielding and work hardening effects in notched bend bars

The stress fields around cracks have been calculated for general yield conditions using two- and three-dimensional elasto-plastic finite-element programmes. These programmes were used to evaluate the Rice J-integral, and compare the values with published data obtained by experimental techniques.

A numerical investigation of post-yield fracture:

Application of the front solution to two and three-dimensional elastoplastic crack problems

http://link.springer.com/content/pdf/10.1007/978-94-009-9574-1_4.pdf

Strip Yielding Model and Fracture Toughnesses of Thin and Tough Plates

In earlier work, A.R. Luxmoore and P.J. Wyatt described measurements of the deformation of zirconium notched bend specimens, using the Moire effect. This deformation has been simulated by a two-dimensional elastic-plastic finite-element program, and small variations of the crack geometry studied. The numerical and experimental results were compared by studying (a) the crack opening displacement, (b) the crack opening profile, and (c) the size and shape of the plastic zones.

P.J. Wyatt

Papers

A comparison of finite-element and experimental studies on the deformation of zirconium notched bend specimens