Research Paper
Composite wood products
Ahmad Jahan latibari; Habibalah Arabtabar; Fardad Golbabaei; Abolfazl Kargarfard; Amir Nourbakhsh; Abbas Fakhryan roghani
Abstract
Laminated beam ( LB.) and laminated veneer lumber ( LVL) manufactured from maple, hornbeam and beech wood is investigated. Three levels of press pressures at 30, 35, 40 kg/cm2, three levels of layer thicknesses of 2, 3, 4 mm and tangential and radial layers are investigated. Bending strength (MOR and ...
Read More
Laminated beam ( LB.) and laminated veneer lumber ( LVL) manufactured from maple, hornbeam and beech wood is investigated. Three levels of press pressures at 30, 35, 40 kg/cm2, three levels of layer thicknesses of 2, 3, 4 mm and tangential and radial layers are investigated. Bending strength (MOR and MOE) and shear strength were measured according to ASTM 1186 and 905 respectively.The results of this investigation indicated that laminated wood strength of samples produced from hornbeam layers is superior to beech and beech is superior to maple. Statistical analysis of the results showed that the effect of wood species on strength properties is significantly different at 99% level. Press pressure also showed significant effect on strength. Increasing press pressure improved bending properties, but the highest shear strength was observed at 30 kg/cm2. Cutting direction did not influence bending strength and only influenced the shear strength. Even though the initial anticipation was the fact that thinner layer will produce stronger laminated wood. But the results or this study showed that layer thickness did not significantly affect strength properties.
Research Paper
Physics and Mechanical Wood
Habibalah Arabtabar; Abdolrahman Hosseinzadeh; Ali Rezanezhad; Ghanbar Ebrahimi
Abstract
The economical importance of railroads and their development in Iran have been caused those annually 500000 wood sleepers to be required, if sleepers are to be maintained in suitable condition. However, the wood resources are also limited, specially producing roadbeds with high classes. For conservation ...
Read More
The economical importance of railroads and their development in Iran have been caused those annually 500000 wood sleepers to be required, if sleepers are to be maintained in suitable condition. However, the wood resources are also limited, specially producing roadbeds with high classes. For conservation of natural resources (Forests) we need to use logs with lower classes as well. The process of lamination can permits manufacturing sleepers from small logs. Therefore, the manufacturing of two half laminated ties (interface vertical or horizontal) were lower. As in Iranian beech is usually used for manufacturing sleepers, in this study it was also utilized to make dowel-laminated sleepers. The results of this study showed that, the processes of impregnation of dowel-laminated sleepers with preservative (Creosote) and depth of its penetration were better established than in usual sleepers. Laboratory test indicated that modulus of elasticity of two half laminated - vertical sleepers was the same as the usual sleepers but this resistance in two half laminated - horizontal sleepers was decreased. Finally after five years exposure under extensive service, tests no failures in dowel-laminated sleepers especially in vertical shapes were observed.
Research Paper
Physics and anatomy
Abdolrahman Hosseinzadeh; Hossein Familian; Kamyar Salehi; Abbas Fakhryan roghani; Fardad Golbabaei; Habibalah Arabtabar; Nayeralsadat Sadraei
Abstract
Eight-nineteen-year-old trees from Eucalyptus intertexta from Sarab bahman experimental Plantation located 160 Km. South west of Shiraz were selected randomly and fell two from each of the four blocks. Form each tree, 10 cm. thick cross-sectional discs at several different heights (3 meters intervals) ...
Read More
Eight-nineteen-year-old trees from Eucalyptus intertexta from Sarab bahman experimental Plantation located 160 Km. South west of Shiraz were selected randomly and fell two from each of the four blocks. Form each tree, 10 cm. thick cross-sectional discs at several different heights (3 meters intervals) were cut and together with remaining boles then transferred to the Alborz Research Center-Karaj for laboratory studies. The laboratory studies included determination of physical, anatomical and mechanical properties as well as chemical compositions of wood. The mechanical properties were evaluated on the ASTM methods for air-dry and green conditions. The following conclusions were drawn from this study:E. intertexta from one site in southern region of Iran has an average specific gravity of 0.86, fiber length of 0.71 mm, fiber diameter of 25.26 mm, lumen diameter of 4.04 mm, cell wall thickness 5.62 mm, cellulose content of 45.95; lignin 28.2; extractives soluble in alcohol - Banzen 4.28 and ash 0.62 percent.It was found that the mean values of modulus of rupture, modulus of elasticity and compression strength-parallel to grain tested at green condition were 74.21 MPa, 8454 MPa and 38.52 MPa and air-dried condition were 123.47 MPa, 14667 MPa and 77.99 MPa respectively. Data are also presented on other mechanical properties such as impact strength, nail withdrawal cleavage and etc.
