Development of an image analysis technique for measurement of Poisson’s ratio for viscoelastic materials: application to leather

The application of a computerised image analysis system to simultaneously measure longitudinal and axial strain in naturally available anisotropic-viscoelastic material like leather is described. The results are used to calculate Poisson’s ratio and indicate that this parameter varies with position and orientation on the hide and depends on the degree of pre-existing fibre orientation. The origins of this dependency can be explained by a simple microstructural model. The practical implication of the findings for detecting lines of tightness (maximum fibre’s orientation)is discussed