Relative contributions of elasticity and viscoelasticity of fibres and inter-fibre friction in bagging of woven wool fabrics

摘要

This paper reports an investigation of the relative contributions of elasticity and viscoelasticity of fibres and inter-fibre friction to fabric-bagging behaviour of woven wool fabrics, by carrying out a series of experiments and applying a mathematical model to simulate fabric-bagging behaviour under the testing conditions. Through a large number of computation experiments, the relaxation time of the fibres, τ, and three weighting coefficients (k3, k4, k5) were determined for eight woven wool fabrics made from different fibres. It was found that the frictional weighting coefficient, k5 and the relaxation time, τ, are constant across all the fabrics, with k5 = 0.1 and τ = 100 seconds. The relative contributions of the elasticity and viscoelasticity of the fibres have a narrow distribution, with average values k3 = 0.6 and k4 = 0.3. These results indicate that the three weighting coefficients and the fibre-relaxation time are relatively stable and insensitive to fabric structural differences. The consistent agreement between experimental results and the mathematical simulation over a range of fabrics shows that the model is quite reliable in simulating fabric-bagging behaviour. Using the identified values of the parameters, we simulated the bagging behaviour of a new set of wool fabrics. Reasonably good agreement between simulation and experimental measurement further confirmed that the three weighting coefficients and fibre-relaxation time are relatively stable and that the identified values can be used to simulate woven-wool-fabric-bagging behaviour with reasonable accuracy.