Elastic Strength of CF under the Uniform Bending about the Moment Axis in the Machine Direction II

Symmetric Strength for Thickness

Abstract

The relations are analyzed among the strengths of single, double wall corrugated fiberboards (SCF, DCF) and their shape and material model. Strength efficiencies E_fs (strength per unit mass for the semichemical corrugated medium (SCP medium)) and E_fk (strength per unit mass for the kraft liner (KL)) are also discussed. Obtained results are as follows;
(1) The maximum value of absolute sterss σ_smax for SCP medimum occurs at the contact positions of KL with SCP medium. The maximum value of absolute sterss σ_kmax for KL occurs on the surface of KL. σ_kmax is larger than σ_smax.
(2) σ_smax and σ_kmax for SCF decrease as the thickness T_s (for SCP medium), thickness T_k (for KL) or height h of the corrugation increase. They increase as the wave length L of the corrugation increases.
(3) σ_smax for SCF decreases, but σ_kmax for SCF increases with the increase of the longitudinal elastic modulus E_k for KL. σ_smax and σ_kmax increase as T_k increases.
(4) E_fs for SCF decreases with increasing Ts, but increases with increasing L or h. Initially E_fk decreases, then increases gradually depending on T_k.
(5) It is suitable to select as large value of h as possible for DCF.