METHOD OF DETERMINING STIFFNESS OF TEXTILE THREAD IN ITS BENDING Russian patent published in 2014 - IPC G01N33/36 

FIELD: textiles, paper.

SUBSTANCE: method of determining stiffness of textile threads in bending with the rounding the cylinder of known radius the thread is placed under load between two supports in the form of stretched threads, then a vertical load "2N" is applied, the horizontal reaction in the supports "Rx" is experimentally determined or calculated, the height of the thread bend "y" and the distance between the supports "X" is determined, the forces "Pkh", "P" and the angle "δo" are determine by the formulas: Pkh=Px-Rx, $$P=\sqrt{Pk{x}^2+N^2},$$ $$\delta o=\frac{\pi }{2}+arctg\left(\frac{Pkx}{N}\right),$$ then the rigidity "H" is determined by solving the system of equations: $$\{\begin{array}{c}\sqrt{\frac{P\cdot l^2}{H}}={\displaystyle {\int }_{\phi A}^{\frac{\pi }{2}}\frac{d\phi }{\sqrt{1-k^2\cdot \sin \left(\phi \right)}}}\\ \delta o=2\arcsin \left(k\cdot \sin \left(\phi A\right)\right)\\ \frac{y}{2}=l\cdot \left(\frac{2k\cdot \cos \phi A}{\sqrt{\frac{P\cdot l^2}{H}}}\cdot \cos {\delta }_o-\left(\frac{2\cdot {\displaystyle \underset{\phi A}{\overset{\frac{\pi }{2}}{\int }}\sqrt{1-k^2\cdot {\sin }^2\left(\phi \right)}d\phi }}{\sqrt{\frac{P\cdot l^2}{H}}}-1\right)\cdot \sin {\delta }_o\right)\\ \frac{x}{4}=l\cdot \left(\left(\frac{2\cdot {\displaystyle \underset{\phi A}{\overset{\frac{\pi }{2}}{\int }}\sqrt{1-k^2\cdot {\sin }^2\left(\phi \right)}d\phi }}{\sqrt{\frac{P\cdot l^2}{H}}}-1\right)\cdot \cos {\delta }_o+\frac{2k\cdot \cos \phi A}{\sqrt{\frac{P\cdot l^2}{H}}}\cdot \sin {\delta }_o\right)\end{array},$$ where Pkh is the resultant tensile force; Px is the load applied to the bent thread; P is resultant of forces Pkh and N; δo is the angle determining the direction of abscissa axis with respect to the direction of the force P in the initial point; N is the half of the vertical load; l is a quarter of the length of the curved thread; φA is the elliptical amplitude in the initial point; k is the elliptical module.

EFFECT: improvement of accuracy of measurement of the thread bending parameters for the subsequent calculation of the thread bending stiffness factor at its longitudinal-transverse bending near the thread imitating the opposite system of threads in the fabric under the action of tensile forces.

1 ex, 2 dwg