U can take support of transverse, axial & volume swelling & find the Poisson's ratio with fractional change in D to fractional change in length (axial).

Ref : Textile Materials and Structures with Negative Poisson's Ratio - An Overview

Ming Zhou, Zhaoqun Du, Guanyi Lu

Dear Izabela Ciesielska.

Based on my little knowledge, polymeric materials such as wool and cotton have nonlinear mechanical behavior as hyperelastic materials. Therefore, if you want to model mechanical behavior of these materials in abaqus, I suggest you use hyperelestic model for this subject and abaqus considers 0.475 for poisson's ratio. You can use uniaxial test data within abaqus.

0,35 in the Abaqus model of this paper : "Mechanical responses and damage morphology of laminated fabrics with a central slit under uniaxial tension: A comparison between analytical and experimental results" Jianwen Chen, Wujun Chen, Bing Zhao, Bo Yao