Method for Calculating the Bending Stiffness of Honeycomb Paperboard.

The article presents continued considerations presented in a prior publication on the development of a model for calculating the bending stiffness of cellular honeycomb paperboards, applying the strength properties of paper raw materials used for the production of paperboard and the geometric parameters of cellular board. The results of calculations obtained by using the analytical model presented in the prior publication were significantly overestimated in relation to the value obtained by measurements. The calculation error in relation to the measurement value for the tested group of paperboards in the case of bending stiffness in the machine direction was within the range from 23% to 116%, and the average error was 65%, while in the cross direction it was within the range from 2% to 54%, and the average error was 31%.

New Models for Calculating the Maximum Compressive Force of Paper in Its Plane.

The main objective of the presented research was to find a model that describes the maximum compressive force of paper in its plane. The research began with crushing tests of a number of packaging paper samples of various lengths. It was shown that due to the specific structure of the paper and the high heterogeneity of its structure, packaging paper is material where it is difficult to determine the maximum compressive stress.

Bending Stiffness of Honeycomb Paperboard.

This article analyzes the influence of the initial deflection of the flat layers on the bending stiffness () of honeycomb paperboards and presents two methods for its calculation. Both methods allow for the determination of in the main directions in the plane of the paperboard, i.e.

Eigenproblem Versus the Load-Carrying Capacity of Hybrid Thin-Walled Columns with Open Cross-Sections in the Elastic Range.

The phenomena that occur during compression of hybrid thin-walled columns with open cross-sections in the elastic range are discussed. Nonlinear buckling problems were solved within Koiter's approximation theory. A multimodal approach was assumed to investigate an effect of symmetrical and anti-symmetrical buckling modes on the ultimate load-carrying capacity.

Some Inconsistencies in the Nonlinear Buckling Plate Theories-FSDT, S-FSDT, HSDT.

Bending and membrane components of transverse forces in a fixed square isotropic plate under simultaneous compression and transverse loading were established within the first-order shear deformation theory (FSDT), the simple first-order shear deformation theory (S-FSDT), and the classical plate theory (CPT). Special attention was drawn to the fact that bending components were accompanied by transverse deformations, whereas membrane components were not, i.e.