Round Robin Prediction of Residual Stresses in the Edge-Welded Beam R6 Validation Benchmark Problem

Abstract

A simple austenitic steel beam specimen with a single autogenous weld bead laid along its top edge is an ideal training problem for novice weld modellers. This geometry may be analysed using either 3D or 2D FE models and employing either block-dumped or moving heat source techniques, with a variety of material constitutive models. This paper describes a residual stress simulation round robin performed on the validation benchmark problem of this type recently added to the R6 defect assessment procedure. A variety of solution strategies of increasing complexity are applied to the problem and the results compared with accuracy targets specified in the validation benchmark. It is found that the greatest solution accuracy is obtained using a 3D moving heat source, and mixed isotropic-kinematic material hardening behaviour.

Evaluation of Errors Associated with Cutting-Induced Plasticity in Residual Stress Measurements Using the Contour Method

“…Despite the overall similarity it is discernible that, for vertical cutting, the cuttinginduced plastic strain associated with the isotropic hardening model is actually slightly larger than that associated with the combined hardening model. This can be attributed to the overestimation of weld residual stresses using an isotropic hardening model [25,27]. However, the effects of cyclic strain hardening may become more pronounced if extensive and significant reverse yielding occurs during cutting, but this is a topic for future work.…”

“…Combined hardening models have been shown to be best suited to describing the cyclic plastic behaviour of austenitic Type 316 stainless steel [25,26]. It has been also demonstrated that the use of combined hardening models and moving heat sources can most accurately capture the residual stresses in stainless steel welds [22,23,25,[27][28][29].…”

“…welding parameters, material properties and processed experimental data, are available in Refs. [21,22] for model validation. This benchmark is an ideal test case (a) for predicting weld residual stresses by FE modelling with sufficient accuracy, (b) for validating a weld FE model using the reported experimental data [20,21] and (c) for using the validated FE model to simulate the entire contour method process.…”

“…The temperature-dependent Lemaitre-Chaboche parameters for the beam material (AISI 316H steel) were obtained by Aird et al [22,27] using appropriate monotonic and cyclic test data, which are also listed in Table 1. Details relating to the combined hardening parameters for stainless steels and their determination are described in Ref.…”

“…[21]. Contour cutting is simulated through the mid-length plane Table 1 Lemaitre-Chaboche combined kinematic-isotropic hardening parameters [22,27] Temperature (°C) σ| 0 (MPa) on the same mesh ( Fig. 5(a)) that was used in the thermal analysis, and a combined hardening plasticity model (LemaitreChaboche) was employed to account for plastic material behaviour [24,25].…”