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1.
Elastic moduli and stiffness optimization in four-point bending of wood-based sandwich panel for use as structural insulated walls and floors 总被引:1,自引:0,他引:1
Tamami Kawasaki Min Zhang Qian Wang Kohei Komatsu Shuichi Kawai 《Journal of Wood Science》2006,52(4):302-310
Several wood-based sandwich panels with low-density fiberboard core were developed for structural insulated walls and floors,
with different face material, panel thickness, and core density. The elastic moduli with and without shear effect (E
L, E
0) and shear modulus (Gb) were evaluated in four-point bending. Generally, the stiffer face, thicker panel, and higher core density were advantageous
in flexural and shear rigidity for structural use, but the weight control was critical for insulation. Therefore, optimum
designs of some virtual sandwich structures were analyzed for bending stiffness in relation to weight for fixed core densities,
considering the manufactured-panel designs. As a result, the plywood-faced sandwich panel with a panel thickness of 95 mm
(PSW-T100), with insulation performance that had been previously confirmed, was most advantageous at a panel density of 430
kg/m3, showing the highest flexural rigidity (E
L
I = 13 × 10−6 GNm2) among these panels, where E
L, E
0, and G
b were 3.5, 5.5, and 0.038 GN/m2, respectively. The panel was found to be closest to the optimum design, which meant that its core and face thickness were
optimum for stiffness with minimum density. The panel also provided enough internal bond strength and an excellent dimensional
stability. The panel was the most feasible for structural insulation use with the weight-saving structure. 相似文献
2.
Manufacture and properties of ultra-low-density fiberboard 总被引:6,自引:0,他引:6
Low-density fiberboards with densities ranging from 0.05 to 0.50g/cm3 were manufactured with steam injection pressing. Bond-type and foam-type isocyanate compound resin adhesives were used separately at 10% and 30% resin content levels. Two types of different-size fibers from softwood were used. Mechanical, dimensional, thermal, and sound insulation properties of the fiberboards were tested. The results are as follows: (1) Bond-type isocyanate adhesive showed higher mechanical and dimensional properties of low-density fiberboards than the foam-type adhesive. (2) Fiberboards produced from small fibers have better mechanical and dimensional properties than those made from large fibers. (3) Thermal conductivity of fiberboards depends more on the board density than on the type of resin or fiber dimension. At a board density lower than 0.2 g/cm3, the thermal conductivity is almost equivalent to those of thermal insulation materials such as polystyrene foam and rock wool, (4) Generally, the sound absorption coefficient of low-density fiberboards tends to increase at higher sound frequency. As the board thickness increases, low-frequency sounds are more readily absorbed by boards.Part of this report was presented at the 46th annual meeting of the Japan Wood Research Society, Kumamoto, April 1996 相似文献
3.
Low-density sandwich panels of veneer-overlaid fiberboards of 12 mm thickness for structural use were manufactured at densities of 0.3–0.5g/cm3 using an isocyanate compound resin adhesive and steam injection pressing method. The effects of board density, veneer thickness, and resin content on the fundamental properties of sandwich panels were examined, with the following results: (1) The dry moduli of rupture and elasticity in the parallel direction of sandwich panels with thicker veneers were superior. The dry moduli of rupture and elasticity in the parallel direction of sandwich panels with 2.0 mm thick veneer at densities of 0.4–0.5 g/cm3 were 40–60 MPa, and 5–8 GPa, which were two and four times as much as those of homogeneous fiberboards, respectively. (2) The higher-density panels exhibited tensile failure at the bottom veneer surface during static dry bending in a parallel direction, whereas lower-density panels experienced horizontal shear failure in the core. (3) The dimensional stability of sandwich panels had good dimensional stability, with negligible springback after accelerated weathering conditions. (4) The thermal insulation properties of sandwich panels were found to be much superior to other commercial structural wood composite panels.Part of this report was presented at the 47th annual meeting of the Japan Wood Research Society, Kouchi, April 1997 相似文献
4.
Tamami Kawasaki Kweonhwan Hwang Kohei Komatsu Shuichi Kawai 《Journal of Wood Science》2003,49(3):199-209
The fundamental in-plane shear properties were investigated for the wood-based sandwich panel of plywood-overlaid low-density
fiberboard (SW) manufactured at a pilot scale to develop it as a shear wall. The shear test method using tie-rods standardized
for shear walls was applied to SW with dimensions of 260 mm square and 96 mm thick as a small shear wall and to plywood (PW)
and thick low-density fiberboard (FB). The shear modulus and shear strength of PW, FB, and SW were determined. To measure
the shear deformation angle, a displacement meter and strain-gauge were used. The shear moduli of PW (0.68 g/cm3) and FB (0.25–0.35 g/cm3) were 460 and 21–58 MPa/rad, respectively. The shear modulus of SW as a composite was analyzed. Some experimental models
of SW were proposed (i.e., rigid-α, rigid-β, flexible, and semirigid models). The shear modulus of SW (0.35–0.40 g/cm3) evaluated based on the rigid-α and semirigid models were 73–89 and 109–125 MPa/rad, respectively. The theoretical shear modulus of SW was calculated to
be 110–129 MPa/rad.
Received: May 9, 2001 / Accepted: June 26, 2002
RID="*"
ID="*" Part of this report was presented at the 50th Annual Meeting of the Japan Wood Research Society, Kyoto, Japan, April
2000; and the 5th Pacific Rim Bio-Based Composite Symposium, Canberra, Australia, December 2000
Acknowledgments The authors express our deep gratitude to Mr. Noritoshi Sawada (Hokushin Co.), Dr. Wong Cheng, and their cooperative members
for their expert technical support for the preparation of manufacturing the thick fiberboard and sandwich panel. We are grateful
also to Drs. Min Zhang, Kenji Umemura, Wong Ee Ding, and Guangping Han for their great help and advice in manufacturing the
thick panels. The authors are grateful to Hokushin Co. for the fiber and resin and to Ishinomaki Gouhan Co. for the plywood.
We thank Mr. Makoto Nakatani for his expert assistance when preparing the specimens for the shear test. Funding provided by
the Research Fellowship of the Japan Society for the Promotion of Science for Young Scientists as a JSPS Research Fellow is
also gratefully acknowledged. 相似文献