Theoretical and experimental determination of average elastic and strength properties of M-ribbed type folded cores

The approximate analytical solution for the direct problem of determining the average elastic and strength properties of M-ribbed type folded cores in transverse tension and compression as well as their shear properties in two mutually perpendicular planes is built. The resulting formulas except for the basic mechanical and geometrical governing parameters contain dimensionless coefficients, which are to be determined by solving the inverse problem on the basis of specially conducted experiments using A. Sachenkov's theoretical and experimental method. The developed technique is used to determine the characteristics of M-ribbed folded cores made of NOMEX polymer paper.