一様曲げ変形（モーメント軸が流れ方向）を受ける段ボールの応力解析 第５報 厚さ方向に非対称な強度をもつ複両面段ボールの場合

Abstract

Analysis of the bending stress is performed for double wall corrugated fiberboard (DWFC) with asymmetrical strength distribution along the direction of thickness of the kraft-liner (KL). Relations are investigated between maximum absolute stresses of elements for DWCF (σs1max, σs2max, σk1max, σk2max and σk0max) and shapes for upper KL (Upper KL1, lower KL2 and middle KL0) or semi-chemical corrugated medium (SCP medium : upper CM1 and lower CM2). Obtained results are as follows ;(1) Vertical distance h0 from the outer surface of KL2 to the neutral surface of DWFC increases with increasing modulus Ek1 of longitudinal elasticity. thickness TK1 for KL, and thickness Ts1 and waveheight h1 for CM1. It decreases initially and then approaches constant gradually with the increase of wavelength L1 for CM1.(2) Stresses in KL and SCP medium are proportional to the distance from the neutral surface to the point interested in. σs1max, σs2max, σk1max, σk2max and σk0max occur at the outermost positions, that is, on the outermost surfaces for CM1, CM2, KL1, KL2 and KL0.(3) σs1max decreases remarkably or slowly with the increase of Ts1, Ek1, Tk1, and thickness Tk0 for KL0 but increases with the increase of L1. It increases initially, attains maximum and then decreases gradually with h1. σs2max increases initially, attains maximum and then decreases gradually with of Ek1, Tk1 and Tk0 It decreases with the increase of Ts1 and h1.(4) σk1max decreases remarkably with the increase of Ts1, Tk1 and Tk0, but increases with the increase of L1 and Ek1. It also increases initially, attains maximum and decreases gradually with the increase of h1.While σk2max decreases with the increase of Ts1 and Tk0, and increases with the increase of L1. But it increases initially, attains maximum and then decreases gradually with the increase of h1, Ek1 and Tk1.