TECHNIQUE TO TEST STRUCTURAL GEOMETRICAL PARAMETERS OF WOVEN MATERIALS Russian patent published in 2001 - IPC

FIELD: optical diffraction methods of nondestructive test. SUBSTANCE: invention is related to optical diffraction method of nondestructive test of structural geometrical periodic parameters of opaque woven cloths of any nature. It can also find use for test of any flat textile cloths transparent or non- transparent for light which are inaccessible for direct diffraction analysis but accessible for photographing, for instance, museum woven specimens. In accordance with proposed technique negative or positive frontal image of tested material placed on any transparent base, for instance, on photographic film, generated by its direct or backward illumination when it is illuminated by parallel beam of monochromatic light with wave length λ perpendicular to its surface can be used in the capacity of tested specimen. Value of structural parameters of tested material is evaluated by symmetry and mutual arrangement of maxima in diffraction picture produced by image of tested material put on transparent base. Density (P_w) of the weft is evaluated by value of distance measured between adjacent rows of basic maxima (ΔX) going in direction of thinned filaments in image of tested material and value (P_wt) of warp texture is evaluated by value of distance measured between adjacent rows of basic maxima ΔY going in direction of filaments of warp texture in image. In this case values P_w,P_wt are calculated by formulas P_w= KΔX/(Lλ);P_o= KΔY/(Lλ) where K is magnification factor of image of tested material which is equal to relation of true dimension of tested material to dimension of its photographic image on transparent base; L is distance from image of tested material to screen. EFFECT: expanded capabilities of diffraction method with reference to any kind of woven cloths. 5 dwg