In order to assess the effect of a residual stress field on the fracture behaviour of materials, a well-defined residual stress field, with known characteristics, such as triaxiality, must be generated in a controllable and reproducible manner. In this paper local compression, or punching, is used to introduce a residual stress field into a cracked plate, and the resulting residual stress field determined using Finite Element Analysis (FEA). However, great care must be taken using this approach, as it is well known that the elastic stress field created by a circular, flat-ended punch contains a stress singularity at the edge of the indenter. It is therefore imperative that, where possible, FE simulations are validated against analytical solutions to ensure confidence in the results. However, there are no analytical solutions for these residual stress fields. FE results for indentation of an elastic half-space are compared to analytical solutions. Results are then presented for the elastic stress field created by punching a finite sized block of material, of dimensions representative of a material test specimen, and the deviations from the half-space results are highlighted. The analysis is then extended into the elasto-plastic regime and the residual stress fields generated for these two geometries after the punching process are given. The residual stress field is measured in the finite sized specimen using deep hole drilling (DHD) and incremental centre hole drilling (ICHD) and compared to the FE predictions. Finally, local compression is applied to a specimen containing a crack. A parametric study is undertaken which examines the influence of the punching tool radius and punching position – relative to the crack tip – on the resulting residual stress field.

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