METHOD FOR DETERMINING LIMIT STATE OF MATERIAL MEDIUM UNDER DIFFERENT CONDITIONS OF ITS LOADING Russian patent published in 2015 - IPC G01N3/08 

FIELD: measurement equipment.

SUBSTANCE: invention relates to Contact Interaction Physics of material medium in a limit state. Essence of the invention consists in the fact that limit state of the test medium is determined as per the following relation: $${\tau }_{med}^c=p_{med}^{c}tg\phi °+с,$$ where $${\tau }_{med}^c$$ and $$p_{med}^c$$ - values of tangential primary stress $$({\tau }_{med}^c={\sigma }_I={\sigma }_{II})$$ and pressure corresponding to primary tensile-compressive stress $$({\sigma }_{III}=p_{med}^c)$$ of the medium under conditions of compression of the medium specimen, and values of normal pressure and normal tangential shear stresses of the medium are defined as: 1) under conditions of uniaxial deformation $${\sigma }_Z=p_{med}^{axis}=\frac{(p_{med}^{c}tg{\phi }_n^o+c_n+p_{atm})\sin {\phi }_{"стр"}^o\cos {\phi }_n^o-{с}_n}{tg{\phi }_n^o}-p_{atm}(kg/c{m}^2),$$ $${\tau }_{med}^{axis}={\tau }_{med}^c\sin {\phi }_{"стр"}^o\cos {\phi }_n^o\text{ (}kg/c{m}^2)$$ - when shear lines come out onto side surface of the specimen and $${\tau }_{med}^{axis}=p_{med}^{axis}tg{\phi }_n^o+{с}_n(kg/c{m}^2)$$ - under die bottom; 2) at deformation of surface of half-space

$${\sigma }_Z=p_{med}^{hs}=\frac{(p_{med}^{c}tg{\phi }_n^o+{с}_n+p_{atm})\cos {\phi }_{"стр"}^o\cos {\phi }_n^o-{с}_n}{tg{\phi }_n^o}-p_{atm}(kg/c{m}^2),$$ $${\tau }_{med}^{hs}={\tau }_{med}^c\cos {\phi }_{"стр"}^o\cos {\phi }_n^o(kg/c{m}^2)$$ - when shear lines come out onto surface of half-space and $${\tau }_{med}^{hs}=p_{med}^{hs}tg{\phi }_n^o+{с}_n(kg/c{m}^2)$$ - under die bottom; 3) at deformation by the die of the vertical opening bottom $${\sigma }_Z=p_{med}^{"скв"}=\frac{(p_{med}^{c}tg{\phi }_n^o+{с}_n+p_{atm}+p_d)/(\cos {\phi }_{"стр"}^o\cos {\phi }_n^o)-{с}_n}{tg{\phi }_n^o}-p_{atm}(kg/c{m}^2),$$ $${\tau }_{med}^{"скв"}={\tau }_{med}^c/(\cos {\phi }_{"стр"}^o\cos {\phi }_n^o)(kg/c{m}^2)$$ - when shear lines come out of the opening walls and $${\tau }_{med}^{"скв"}=p_{med}^{"скв"}tg{\phi }_n^o+{с}_n(kg/c{m}^2)$$ - under the die bottom, where p_d=(γ_”стр”h-c_”стр”)ctgφ_”стр” (kg/cm²) - domestic gravitational pressure; 4) at deformation of the medium in closed massive $${\sigma }_Z=p_{med}^m=\frac{\left[(p_{med}^{c}tg{\phi }_n^o+{с}_n+p_d)/(\cos {\phi }_{"стр"}^o\sin {\phi }_n^o)\right]-{с}_n}{tg{\phi }_n^o}(kg/c{m}^2),$$ $${\tau }_{med}^m={\tau }_{med}^c/(\cos {\phi }_{"стр"}^o\sin {\phi }_n^o)(kg/c{m}^2)$$ - when shear lines come out into the cavity above the die and $${\tau }_{med}^m=p_{med}^{m}tg{\phi }_n^o+{с}_n(kg/c{m}^2)$$ - under the die bottom.

EFFECT: providing possible determination of normal pressure and normal tangential shear stresses of the medium under conditions of uniaxial deformation, at deformation of half-space surface, and at deformation by the die of the vertical opening bottom.

5 cl, 4 dwg