The Relationship Between Fractal Dimension Of Ply Yarn And Yarn Structure And Strength And Elongation

Fractal theory is a science newly developed in the past 20 to 30 years,the study of which has broadened the knowledge form nature structure.The hierarchy structure of tendon and wool is a kind of special fractal structure.Through the study we discovered their fractal dimension is close to the golden section,which explained the tendon with high storage and transmission energy performance and wool with good warmth from their microcosmic structure.Transverse and longitudinal section of the ply yarn is a special kind of fractal structure,with different fineness or different twisting count,it can produce different fractal dimension of ply yarn. Therefore,this paper gives fractal dimension formula of the ply yarn and tries to apply this theory to explore the relations between fractal dimension of ply yarn and yarn structure and strength.The following several parts are involved in this paper.One is the relationship between ply yarn transverse fractal dimension and single yarn geometric arrangement in the ply yarn.Three,four,six ply yarns are studied,and it appears that under the same condition single yarn arrangement tend to high transverse fractal dimension.The reason is that with the lateral fractal dimension increasing,spatial structure is more stable.The second one is through the strength & elongation performance test of three,four,six ply yams,we explore the relationship between mechanical properties and longitudinal fractal dimensions of ply yarn.It appears that with the longitudinal fractal dimension increasing,breaking strength will increase and after a certain value the strength begins fluctuate.Breaking elongation of three,four,six ply yarn is exponentially correlation to the fractal dimension.The relations can be expressed asΔL=a+bexp(π+(8ln4(D_z-1)^1/2)).And the breaking elongation of six ply yarns is bigger than others.Two or more single yarns merge and twist into compound yarn,which merge and twist into complex ply yam.It can be used as sewing thread,jacquard yarn,ropes and so on.Based on three, four,six ply yarn analysis,it is found that three compound yarns'strength value is higher,so this paper chooses three for small teams,and its twisting count with 40 and direction with ZSZ,to produce 3×3 and 3×2 complex ply yarns.By comparing,it is found that the breaking strength of 3×3 complex ply yams is superior to 3×2 complex ply yams.This is due to the 3×3 complex ply yarns has good similar structure.