抄録
The twisting effect for the Young's moduli and the internal friction of many yarns, viz, cotton, viscose rayon, nylon and wool, is observed under the constant tention. The yarns are divided into three classes roughly. (1)The case of long fibers:In the case of uniform tension for each fiber, E・σ(E is Young's modulus and σ is apparent section area)decreases with increase of the degree of twist form the beginning. In the case of non-uniform tension, E・σ increases first with increase of the degree of twist and begins to decrease at some degree of twist. (2)The case of short fibers:E・σ and the internal friction Q^<-1> are alike to the latter case of(1). (3)The case of wool:Q^<-1> has the maximum value at some degree of twist. In the both cases of long and short fibers, the increase of E・σ and the decrease of Q^<-1> are due to the increase of apparent section area of fibers uuder the non-uniform tention by twisting, and the decrease of E・σ and the increase of Q^<-1> are due to the slack of the inner fibers of yarn. The maximum value of Q^<-1>, in the case of wool, is due to the mutual friction of wool fibers.
