Evaluation of normalisation methods for uniaxial bias extension tests on engineering fabrics

Abstract

An investigation has been conducted to evaluate the performance of normalisation methods for the uniaxial bias extension test. The predictions of two published theories for rate-independent behaviour are examined and a third heuristic method is proposed. Using hypothetical test data, the predictions of the two rate-independent theories are shown to be equivalent for specimen dimensions of high aspect ratio; in this case the predictions can be well-represented using the simple heuristic formula. The predictions diverge for specimens of low aspect ratio, when specimens are sheared to very high shear angles. In order to examine the significance of this divergence on real data, results from tests on several different engineering fabrics are normalised.Differences in the predictions of the normalisation methods are observed and the question of the significance of these differences is discussed. The paper also examines the applicability of rateindependent theory for normalising rate-dependent materials.

Shear behavior of a shear thickening fluid-impregnated aramid fabrics at high shear rate

“…Normalization of the data was required to reveal the shear properties of the STF-im-AR fabric, independent of the specimen size and test method. By considering the stress generated by deforming a sample, Harrison et al [47][48][49] developed the following approximate normalized shear force, which is suitable for rate-dependent materials tested using the BE test method: …”

Corrigendum to ‘Evaluation of normalisation methods for uniaxial bias extension tests on engineering fabrics’

“…As a result, some of the conclusions of that investigation should be revised. The following correction is intended to be read in conjunction with the discussion of [1].…”

“…The 'reasonableness' of the predictions was then assessed. It has since become apparent that the measure of accuracy used to decide which of the two theories was more accurate in [1] was incorrect. As a result, some of the conclusions of that investigation should be revised.…”

“…The aim of the current paper is to discuss an error and revise the conclusions of [1], in order to improve understanding on this topic. In [1] the performance of two independently published theories was evaluated.…”

“…In [1] the performance of two independently published theories was evaluated. Three different hypothetical shear force versus shear angle behaviours were postulated and fed into the normalisation theories.…”