METHOD TO DETERMINE EVEN TENSION OF MEMBRANE FROM ISOTROPIC MATERIAL Russian patent published in 2013 - IPC G01L5/04 H04R7/00 

FIELD: measurement equipment.

SUBSTANCE: membrane is jammed by two rings arranged at different sides of the membrane surface, and transverse load is applied, distributed along the area of the circle, the centre of which matches with the centre of jamming rings, the value of maximum membrane sagging is measured, and even tension of the membrane is determined σ ⁽⁰⁾ in accordance with the formula

$${\sigma }^{(0)}=\frac{P}{2IH\pi },$$ $$I={\displaystyle \underset{d}{\overset{b}{\int }}\left[B^2\left[1-\frac{1}{\sqrt{1+H^2{B}^2}}\right]-\frac{1}{r}{\displaystyle \underset{b}{\overset{r}{\int }}\frac{B_2}{\sqrt{1+H^{2}B{\text{}}^2}}dr}\right]rdr},$$ $$B=\frac{4b^2{r}^2\ln \frac{r}{b}+2b^2(d^2+r^2)-2r^2(b^2+d^2)}{r\left(b^4-d^4+4b^2{d}^2\ln \frac{d}{b}\right)}.$$ Where σ⁽⁰⁾ - value of even tension of the membrane, N/m. P - value of transverse load, N. H - value of maximum sagging of the membrane, m; b - inner radius of jamming rings, m; d - radius of the circular site, along which the load is distributed, m.

EFFECT: development of a simple universal method to detect even tension of a membrane based on its local deformation.

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