The inclusion of short-transverse displacements in the eigenstrain reconstruction of residual stress and distortion in in740h weldments

Abstract

The purpose of the present study is to predict the residual stress and distortion of Inconel Alloy 740H componentns during the fabrication of welded components used for advanced ultra-supercritical technology by means of solving the inverse eigenstrain problem. The proposed model determines the distribution of two components of eigenstrain using two-dimensional displacement data obtained from high precision coordinate measurements. Input for the model is provided by the geometric characterisation of electric discharge machining (EDM) sectioned weld bead on plate sample, namely, the out-of-plane distortion of a transverse thin section across the weld line. The deplanation of the original sample is used for cross-validation using the contour method approach, modified recently by the present authors on the basis eigenstrain-based analysis. After determination of the distribution of eigenstrain components, residual stress and displacement calculations are performed in the whole body of as-welded and heat-treated plate models. Results are first verified using experimentally determined residual stress, displacement and distortion on the sectioned surfaces. In addition, 12 mm slices are cut from both model geometries and calculations are repeated using previously determined eigenstrain distributions. Measured distortions on the surface of bar models allowed a fourth term for verification of the eigenstrain distribution.