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| PDF : |  12010015.pdf |
| title(En) : | Studies on Mechanical Properties of Plywood. I. On Specific Gravity and Shear Strength |
| author(En) : | Motoaki Okuma |
| information : | Mokuzai Gakkaishi 12(1), 15-20 (1966) |
| assort : | Original Article |
| summary(En) : | A systematic investigation has been undertaken to provide mechanical data on plywood. The first results of the investigation presented in this report are those of specific gravity and shear strength. Plywood for test was made of rotary cut Bagtikan veneer (thickness 1mm and 2mm, specific gravity 0.585) in our laboratory. Urea resin adhesive was used and press condition was 120°C, 10 kg/cm2, 1 min for 1 mm thickness of plywood. Experimental results are summarized as follows : 1) The specific gravity of plywood has a linear relation with coefficient f (cf. the remark of Table 2). Comparing the experimental formula with the theoretical one, the average thickness of the glue line is calculated to be 0.0218 cm. 2) The shear strength test was made by the JIS method of wood shearing test (Figs. 3 and 4). σs90 + σs0 and σs90 + σs0 [σs90 and σs0 are shear strength (kg/cm2), cf. the remark of Table 2] have also linear relations with f and K0 (Figs. 5 and 6). K0 is the coefficient of plywood construction (cf. the remark of Table 2). These facts lead to formulae by which we can calculate shear strength of plywood from their construction. Then shear strength of veneer (s1, s2) and glue line (sr12) in plywood were calculated (s1, s2, sr12 : cf. the remark of Fig. 7). s1 = 45.2 (kg/cm2), s2 = 93.0 (kg/cm2), sr12 = 445.3 (kg/cm2). |