Modelling of changes of residual cyclic deformation of threads during periodical tension

The influence of exploitation and technological factors on deformation state of sewing threads is investigated in this article. The following characteristics are used as the factors: work of thread extension during footwear lasting, time and speed of loading. Residual deformation is used as a measure of correlation between strain and deformation which first occurs in the thread during stitch lasting and during product exploitation further on. This measure is also used to estimate the deformation and strain state of sewing threads. On the base of the research results the simulation test of residual cyclic deformation with the use of dimension theory was fulfilled. The model of dependence of residual cyclic deformation on exploitation and technological factors is developed. This model can be used in the problems of footwear durability prediction made with the use of sewing thread junction.