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Average plastic properties of friction stir-welded AA2024-T3 are obtained by coupling novel small punch beam testing with a neural network algorithm. The small punch beam test utilizes a cylindrical punch head and miniature rectangular beam specimens. The specimens may be manufactured by material removed from in-service components with minimal effect on mechanical performances. Specimen preparation, material model, and identifying procedure are systematically presented. Predicted load–displacement results agree well with the experimental results and the identified strain–stress relationship demonstrates useful agreement with tensile test. Since the load–displacement curve is insensitive to base material properties, knowledge of these properties is not required in the proposed method. [ABSTRACT FROM PUBLISHER]

A novel vertex-centred finite-volume (FV) method is presented for determining the displacement field in loaded 2D structures. The solid is discretized into 6-node finite elements (FE) and the standard 6-node FE shape function is employed to describe the displacement variation in each element. However, the displacements of the midside nodes are replaced with the displacements and the rotations of the two neighbouring edge nodes. Thus, only the control volumes centred around each vertex node of the triangular element are required. These control volumes are constructed by joining lines between the centre of the element and the midside nodes. The force equilibrium in two perpendicular directions and one in-plane moment equilibrium equation is derived for each control volume. By solving the system of equations, the displacements and the rotations of the vertex nodes can be obtained and then the displacements of the midside nodes can be calculated. Following this, the strain and the stress can be determined through the relationship between strain and displacement, and stress and strain, respectively. The results of simulation show that this novel FV method is not only better than the previously derived 3-node triangle FV method with rotational degrees of freedom, but also better than the 3-node FE method with rotations, and can also compete with the 6-node triangle FE method. In addition, no locking problem was encountered as the value of Poisson's ratio of the elastic material approached 0.5. Copyright © 2010 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]