P.F. Britton

Image tensor analysis: a numerical tool for data acquisition and constitutive analysis of historic continua

Image measurement based on the Fast Fourier Transform convolution theorem has been combined with a finite difference algorithm to produce image tensor analysis (ITA), a numerical tool for experimental determination of deformation for historic continua. ITA allows the deformation within an image-compatible material body to be quantified using digital video footage taken from experimental events. Hence the deformation output from computational modelling of the same event can be directly compared to the measured deformation field given by the image-based numerical solution. The current research application of ITA aims to provide experimental deformation data and characterisation of the constitutive behaviour of the fibro-porous media prepared sugar cane. This paper outlines the numerical procedure of ITA and details the possible post processing applications with respect to both data acquisition and constitutive modelling.

Application of Image Measurement and Continuum Mechanics to the Direct Measurement of Two-Dimensional Finite Strain in a Complex Fibro-Porous Material

This paper outlines a computational procedure that has been implemented for the direct measurement of finite material strains from digital images taken of a material surface during plane-strain process experiments. The selection of both hardware and software components of the image processing system is presented, and the numerical procedures developed for measuring the 2D material deformations are described. The algorithms are presented with respect to two-roll milling of sugar cane bagasse, a complex fibro-porous material that undergoes large strains during processing to extract the sucrose-rich liquid. Elaborations are made in regard to numerical developments for other forms of experimentation, algorithm calibrations and measurement improvements. Finite 2D strain results are shown for both confined uniaxial compression and two-roll milling experiments.