Yarn Deformation with view of its structural structure

The aim of this research is to implement suitable model for estimation mechanical properties of spun yarn. The behavior of fibers in the initial stage of their loading, which are oriented in the direction of the action of the load, is considered. The location of the fibers along the spiral lines has been studied, which leads to reduction in the cross section of the yarn as a result of the approach of the fibers. It is revealed that when the axial force is removed in the fibers, irreversible deformations remain, and in some fibers, residual stresses. This leads to an uneven distribution of strain across the section and it is one of the reasons for the structural unevenness of the yarn. It is established that the time for the realization of the internal resource of the yarn depends on the properties of the raw materials used, the way the yarn is formed, the condition of its winding and other factors. Two types of yarn are considered - compact and conventional, and the change in their deformation in time has been experimentally investigated. Various rheological models were used to develop the patterns of yarn deformation, taking into account the change in its structure during the loading process. The evaluation of yarn deformation taking into account its structure was performed using the Kelvin model with time-variable parameters, which take into account the instant and long modulus of elasticity of the material and the increase in strength characteristics of compact yarn is proved.