Peculiarities of Specimen Preparation for the Investigation of Woven Structure Deformations using Image Analysis

Abstract

The paper presents a method based on non – contact image analysis, which allows to simplify experimental process and increase measurement accuracy, identifying local deformations of woven material. Striving to gain accuracy of image analysis results, specimen preparation and deformation process fixation stages are of great importance. For the studies differently marked specimen groups were prepared. Their behaviour in process of tension was analysed using a special calibrated image acquisition system. Using digital images of deformed specimen the displacement of the marked surface elements - points and their shape changes were measured and material deformations in separate specimen parts (A and B) were described. According the obtained results zones of uniform deformations were established and it confirmed that stretched specimen was deformed unevenly. Mild deformations obtained in part A and the highest values of deformation recorded in the centre of part B: local deformations in the transverse to tension direction were set up to -42.9 % and 27.6 % of local elongation along tension direction. Results of local deformation variation explain buckling phenomenon of bias stretched fabric. Particular local deformation values allow us to describe behaviour of deformed material, bring opportunities to perform experimental and modelling comparison of the results. The suggested methodology could be applied for the investigation of differently deformed material behaviour.

DOI: http://dx.doi.org/10.5755/j01.ms.19.1.3830