The Principle of Strain Reconstruction Tomography: Determination of Quench Strain Distribution from Diffraction Measurements

TL;DR

This paper introduces a method for reconstructing three-dimensional residual strain distributions within objects using high energy X-ray diffraction, demonstrated on a quench-induced axisymmetric strain in a cylinder.

Contribution

It presents the principle of strain tomography from diffraction data, enabling the reconstruction of complex strain fields from reduced measurements, with potential for broader applications.

Findings

Successful demonstration on a cylindrical sample with quench-induced strain

Method enables interpretation of finite resolution diffraction data

Principle can be generalized to complex strain states

Abstract

Evaluation of residual elastic strain within the bulk of engineering components or natural objects is a challenging task, since in general it requires mapping a six-component tensor quantity in three dimensions. A further challenge concerns the interpretation of finite resolution data in a way that is commensurate and non-contradictory with respect to continuum deformation models. A practical solution for this problem, if it is ever to be found, must include efficient measurement interpretation and data reduction techniques. In the present note we describe the principle of strain tomography by high energy X-ray diffraction, i.e. of reconstruction of the higher dimensional distribution of strain within an object from reduced dimension measurements; and illustrate the application of this principle to a simple case of reconstruction of an axisymmetric residual strain state induced in a cylindrical sample by quenching. The underlying principle of the analysis method presented in this paper can be readily generalised to more complex situations.