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Chand N. Shukla M. Sharma M.K. 《世界竹藤通讯》2008,(3):47-47
竹子从中心到表皮的抗拉强度在72.8—187.3MPa。这表明竹子的梯度抗拉特性。实验数据与用ABAQUS进行的FEM分析相符。表皮部的最大抗拉强度为187.3MPa。存在这样大的抗拉强度的原因是,相比表皮部分存在前最多的的无定形物材料,如薄壁组织。所测定的密度和硬度值也证明这些数值从中心部分存在着梯度变化。 相似文献
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Zhuo-Ping Shao Chang-Hua Fang Sheng-Xia Huang Gen-Lin Tian 《Wood Science and Technology》2010,44(4):655-666
Bamboo is a fiber-reinforced bio-composite since its culm wall is mainly composed of parenchymatous ground tissue in which
vascular bundles are embedded. In order to analyze the mechanical properties of bamboo as a function of its components, tensile
tests were performed on bamboo blocks and the corresponding volume fractions of fiber and parenchymatous ground tissue were
measured. More significant linear relationships were found between tensile properties and volume fractions of the bamboo components.
The tensile strength and modulus of elasticity of bamboo fiber and parenchymatous tissue were estimated according to the linear
equations obtained by regression analysis. The macrographs of fractured bamboo blocks and the micrographs of fracture surfaces
obtained by scanning electron microscope were also analyzed. Further tensile tests on separated bamboo fiber bundles were
analyzed. Results show that the tensile strength of bamboo fiber obtained from the tests on bamboo blocks was higher than
that on separated fiber bundles. This might be due to the interaction between components in bamboo in which parenchymatous
ground tissue can pass loads and distribute the stresses loaded on fibers. 相似文献
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This experiment explored the technical feasibility of using bamboo zephyr mat with pre-hot-pressed treatment for the manufacture of laminated bamboo lumber (LBL), which is similar in construction to that of laminated veneer lumber (LVL). Six LBL boards (made from four-ply bamboo zephyr mats) with approximate dimensions of 2×42× 42cm were fabricated using resorcinol-based adhesive. The experimental design involved three combinations of layered structures (types I, II, and III) and two LBL loading positions (H-beam and V-beam) during the bending test. These materials were then compared to ordinary LVL. Results indicated that the bending properties (moduli of rupture and elasticity) of LBL were comparable to those of LVL, but there was no significant effect on the physical and mechanical properties among the three types of LBL beam. Interestingly, orienting the glue line to the vertical direction (V-beam) could maximize the ultimate strength of the LBL.Part of this research was presented at the 49th Annual Meeting of the Japan Wood Research Society, Tokyo. April 1999, and at the Pacific Timber Engineering Conference, Rotorua, New Zealand, March 1999 相似文献
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Development of structural composite products made from bamboo I: fundamental properties of bamboo zephyr board 总被引:2,自引:0,他引:2
A study was conducted to determine the suitability of zephyr strand from moso bamboo (Pyllostachys pubescens Mazel) for structural composite board manufacture. Thirty-two 1.8×40×40cm bamboo zephyr boards (BZB) were produced using four diameters of zephyr strand (9.5, 4.7, 2.8, and 1.5mm) and four target densities (0.6, 0.7, 0.8, and 0.9g/cm3). Results indicate that BZB exhibits superior strength properties compared to the commercial products. The size of the zephyr strand and the level of target density had a significant effect on the moduli of elasticity and rupture, internal bond strength, water absorption, and thickness swelling, but they did not have a significant effect on linear expansion. With regard to the physical properties, BZB exhibited less thickness swelling and exhibited good dimensional stability under dry-wet conditioning cycles.Part of this research was presented at the 48th annual meeting of the Japan Wood Research Society, Shizuoka, April 1998; it was reported at the 4th Pacific Rim Bio-Based Composite Symposium, Bogor, Indonesia, November 1998 相似文献
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Differences in the water adsorption properties of moso bamboo (Phyllostachys pubescens) were examined by analyzing the isotherms. Hygroscopicity decreased from the bottom to the top of the culm, and this tendency was marked above about 80% relative humidity. Results of alkali extraction and the analysis of bundle sheath distribution revealed that the distribution of hygroscopic saccharides, for example, hemicelluloses and less-hygroscopic vascular bundles, affects the hygroscopicity, which varies depending on the position of the internode. 相似文献
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Zhijia Liu Benhua Fei Zehui Jiang Zhiyong Cai Xing’e Liu 《Wood Science and Technology》2014,48(5):903-917
Bamboo is a type of biomass material and has great potential as a bio-energy resource of the future in China. Some properties of bamboo pellets, length, diameter, moisture content (MC), particle density, bulk density, durability, fine content, ash, gross calorific value, combustion rate and heat release rate, were determined and the effects of MC and particle size (PS) on these properties were investigated in this research. The results showed that bamboo pellets will be the proposed new biomass solid fuel and have the potential to be developed as commercial pellets. All properties of bamboo pellets met the requirement of Pellet Fuels Institute Standard Specification for Residential/Commercial Densified Fuel. The gross calorific value of bamboo pellets also met the minimum requirement for making commercial pellets according to DIN 51731 (>17,500 J/g). The effects of MC on length, diameter, MC, particle density and bulk density were significant at p = 0.05. There were no significant differences between PS and all properties of bamboo pellets. Due to higher MC and larger PS, bamboo pellets exhibited higher combustion rates and heat release rates. This research represents an initial stage in the study of bamboo pellets, and its objectives provide guidelines for further research. 相似文献
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不同海拔毛竹土壤酶活性与土壤理化性质关系的研究 总被引:4,自引:0,他引:4
以江西省大岗山地区的毛竹林为研究对象,利用相关分析和主成分分析对不同海拔(300、400、500、600、700m)土壤纤维素酶、蔗糖酶、淀粉酶、β-葡糖苷酶和多酚氧化酶活性的变化特征进行了分析,探讨了其与土壤理化性质的关系。结果表明:土壤化学指标表现出随海拔的升高而增加的变化特征,除碱解氮外,其他各指标均处于较低水平,但物理指标的变化各不相同;随海拔升高,β-葡糖苷酶与多酚氧化酶活性呈现出增加的趋势,而纤维素酶、蔗糖酶和淀粉酶活性无明显变化规律;几种土壤酶对土壤肥力的指示效果不同,β-葡糖苷酶在评价毛竹林土壤肥力上具有重要指示效果,其后依次为蔗糖酶和多酚氧化酶、纤维素酶,但淀粉酶不适宜用来评价土壤肥力状况;通过主成分分析计算综合得分,不同海拔毛竹土壤肥力随海拔的升高而增加。 相似文献
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This study investigated the liquefaction of bamboo in phenol, which involved the effects of weight ratios of phenol to bamboo,
amount of catalyst, temperature, etc. The study showed that liquefaction could be accomplished with a phenol to bamboo weight
ratio of 2–1: 1, a 5% catalyst of HCl or BF3, and a temperature of 115°C. Liquefied bamboo formaldehyde (BLF) resin adhesive for exterior use could be obtained with a
phenol to formaldehyde molar ratio of 1:1.6–2.0. The curing behavior of BLF resin adhesive, studied by TG-DSC and IR analyses,
showed that BLF resin adhesives had a lower curing temperature than PF adhesives but had the same characteristic trough in
IR spectra as PF adhesives.
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Translated from Chemistry and Industry of Forest Products, 2004, 24(3) [译自: 林产化学与工业, 2004, 24(3)] 相似文献
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The effects of chemical treatments (H2O2 + CH3COOH, acidified NaClO2, and NaOH) and freeze-drying on bamboo fibers were studied at a submicron level, to characterize chemical and mechanical changes to the secondary cell wall. Specifically, a field emission environmental scanning electron microscope (FE-ESEM) and imaging fourier transform infrared spectroscopy (FTIR) were used to demonstrate degradation in morphology and molecular structure, and nanoindentation was used to track changes in micromechanical properties. The results showed that cellular structures after chemical treatments clearly displayed wrinkles, pores, and microfibrils. The decreased bands at 1508 cm-1 and 1426 cm?1 showed that lignin was degraded on treatment of H2O2 + CH3COOH and acidified NaClO2, which directly resulted in a decrease in hardness (H) in the secondary cell wall for treated fibers. In addition, a diminishing peak at 1733 cm?1 caused by NaOH solution indicated that hemicellulose was seriously degraded. It resulted in a decreased modulus (E r) by 13.71 % in bamboo fibers, while no obvious reduction was observed in the first two steps. 相似文献
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