In this study, we estimated the element strength distribution of Laminated Veneer Lumber (LVL) by the nonlinear least-squares method, supposing an element of veneer with adhesive. However, in order to validate this method, we must compare the element strength distribution estimated by this method with that calculated from experimental data. Then, we extracted specimens of 1ply, 2ply and 3ply with an adhesion layer from the remainders of LVL and carried out the same static tests as the experiments for LVL. Comparing the experimental values of 1ply and the estimated values in the previous report, the latter were larger than the former for Modulus of rapture (MOR) in the horizontal and vertical use directions, and tension and compression strengths. Accordingly, a laminating effect was suggested by those strengths. To ascertain this, the strength distributions of 2ply and 3ply were simulated by the experimental data of 1ply. Also the population distributions for the strengths of 2ply and 3ply were estimated by the maximum likelihood method. Comparing the strength distributions simulated by 1ply with the population distributions, the population distribution was larger for MOR in the vertical use direction, tension strength and compression strength. Therefore, in those strengths, it turned out that the laminating effect existed. On the other hand, we could not determine whether or not the laminating effect existed for MOR in the horizontal use direction.

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In this study, we investigated the characteristics of benzylated wood meal, prepared by a mechanochemical and a liquid phase method. Fourier transform-infrared (FT-IR) spectra, thermogravimetric (TG) curves, thermal flow properties, and crystallinities were measured. Benzylated wood meals of weight percent gain (WPG) from 11% to 78% were prepared by both methods. According to the FT-IR analysis, the mechanochemical and liquid phase benzylated woods showed the same tendency of relative intensity at 699cm^-1 and 3450cm^-1. According to the TG analysis, the mechanochemical benzylated wood showed different thermal decomposition characteristics compared with the liquid phase benzylated wood. The temperature at which thermal decomposition was initiated for the mechanochemical benzylated wood decreased as the WPG increased. According to the thermal flow analysis, the mechanochemical benzylated wood showed a smaller decrease in outflow temperature as the WPG increased, compared with the liquid phase benzylated wood. The crystallinities of the mechanochemical and liquid phase benzylated woods decreased as the WPG increased. However, the mechanochemical benzylated wood maintained a crystallinity of 10%, when the WPG was from 20% to 60%.

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Uniaxial tensile tests were conducted for off-axis copy paper to obtain stress-strain curves. It was shown that the stress-strain responses strongly depend on the off-axis angles. The nonlinear regions of the off-axis angle-dependent stress-strain relationships were transformed into the equivalent stress-equivalent plastic strain counterparts based on the mathematical theory of plasticity taking into account a Hill-type anisotropic yield criterion. The equivalent relationships were demonstrated to coincide almost uniquely regardless of the off-axis angles. This implied that the nonlinear stress-strain responses of copy paper can be predicted appropriately by using the mathematical theory of plasticity.

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There is no regulation for wood preservatives in the Japanese Agricultural Standard (JAS) for glued laminated timber. Glued laminated timber (GLT) treated with wood preservatives is not qualified as a JAS product and we cannot use it for quasi-fireproof construction material considering the charring rate during accidental fire. It is necessary to clarify that the incising process and impregnation of chemicals do not affect the fire safety of treated GLT in order to use it just the same as normal GLT. Treated GLT beams whose laminae were incised mechanically and impregnated with wood preservatives (alkyl ammonium compound (AAC) or azole neonicotinoid compound (AZN)) were made for a 45-minute-quasi-fireproof test. The beams were not destroyed during the fire test and their char depths were less than 35 mm. The fire performance was the same as of a normal GLT beam. The results of vacuum-pressure delamination tests met the requirement for use environment A.

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