About Freeword: "plywood"
 List  | Prev.  | Next
PDF : 05040127.pdf
title(En) :Shearing Moduli of Plywood, Hardboard and Particle Board
author(En) :Shitomo Mamada, Junya Yamada, Shinji Hirai
information :Mokuzai Gakkaishi 5(4), 127-130 (1959)
assort :Original Article
summary(En) :   This paper describes how the plate shear test shall be applied in measuring the shearing moduli of plywood, hardboard and particle board. A series of experiments were conducted with square plates loaded at corners just as the ASTM Standard test procedure to check the accuracy of the theory of isotropic plates.
   An experimental arrangement was prepared as shown in Figs. 1 and 2, to apply four equal loads at the corners of a square plate, two loads at the extremity of one diagonal acting downward, and two at the extremity of the other diagonal acting upward.
   From the theory of isotropic plate, the following equation is introduced, in which w is the deflection at |he point of the distance u from the center on the diagonal,
                  w = (3Pu2)/(2Gh3)
where, P is the total load applied to corners, h is the thickness of the plate, and G is the shearing modulus.
   It follows that
                  G = (3u2P)/(2h3w)
   The physical properties and Young's moduli of test boards are shown in Table 1.
   The test results are as follows:
   The relation between the shearing modulus and the ratio of length of edge a to thickness of the specimen h are shown in Figs. 3, 4, 5, and 6.
   These indicate that the values of shearing moduli are calculated from the equation affected by the length-thickness ratio a/h.
   It might be reasonable to make specimens have values of the ratio within 20 - 50.
   Generally speaking, this measuring and calculating method of shearing modulus might give satisfactory results for hardboard and particle board, but there are several disturbing factors inherent in plywood such as ply-construction, quality of veneer and the glue used.