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木材顺纹压缩弹塑性和PDR(永久变形率)变化规律及机理研究是攻克木材顺纹压缩与多维弯曲技术的核心.从木材的树种、密度、软化处理条件、化学组分和相对结晶度以及压缩速度几个方面,分析了木材顺纹压缩过程中这些因素对木材顺纹压缩率和PDR的影响机制. 相似文献
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大花序桉木材顺纹抗压强度变异研究 总被引:4,自引:0,他引:4
以18 a生的11个大花序桉种源木材为研究对象,分析了种源间、单株间、树干高度上的木材顺纹抗压强度的变异情况,结果表明.大花序桉部分种源间、株间及高度间木材顺纹抗压强度均有显著差异,B85号种源的顺纹抗压强度最大,为83.4 MPa;12195号种源的最小,为69.8 MPa,并显著小于B85、17008等6个种源.各种源木材顺纹抗压强度沿树干高度的变化并不相同,有的呈递增趋势,有的呈递减趋势,有的先增后减,有的先减后增.因此,在种源选择基础上,应进一步进行单株选择,以便在更大程度上提高大花序桉木材顺纹抗压强度改良效果.大花序桉种源木材顺纹抗压强度和树高、胸径等生长性状相关性不明显,可相互进行独立改良,因而可望同时获得生长快和木材顺纹抗压强度高的改良成效. 相似文献
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《中南林业科技大学学报(自然科学版)》2016,(6)
为增强杜仲全树开发的力度,提高木材利用价值,按照国家行业标准对杜仲木材的密度、顺纹抗压强度、硬度和握钉力4个力学指标进行了研究。结果表明:杜仲木材的密度范围在0.63~0.70 g/cm3之间,平均密度为0.67 g/cm3;顺纹抗压强度平均达47.72 N,显著高于黄榆木、文县杨;平均硬度达6215.50 N;握钉力为49.92 N/mm。杜仲木材具有较好的力学性能,是优良的商品木材原料,可广泛用于家具制造、木质工艺品、建筑等领域。 相似文献
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人工林杉木和杨树木材物理力学性质的株内变异研究 总被引:4,自引:0,他引:4
按照中国国家标准研究杉木和I-214杨树木材的抗弯弹性模量、抗弯强度、顺纹抗压强度和密度,同时按照日本国家标准研究2个树种的顺纹抗剪强度.结果表明:杉木的抗弯强度、顺纹抗压强度和密度由胸高直径处向上呈波浪形增加,抗弯弹性模量则稳定降低,但不同高度间杉木的物理力学性质没有显著差异;近树皮处木材的物理力学性质高于近髓心处木材,并有极显著差异.对于I-214杨树,只有抗弯弹性模量从髓心到树皮逐渐增加,其他的物理力学性质,最小值在从髓心到树皮的过渡区,最大值在近树皮处,从髓心到树皮,杨树的物理力学性质有极显著的差异.杉木和杨树的径面顺纹抗剪强度从髓心到树皮有极显著差异,并且近树皮的高于近髓心的木材,而弦面顺纹抗剪强度从髓心到树皮没有显著差异.木材密度与力学性质有很好的线性相关关系,木材密度是一个很好的力学强度的预测手段. 相似文献
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杉木材性株内变异的研究Ⅰ.木材力学性质和木材密度 总被引:2,自引:0,他引:2
对15株浙江产杉木株内不同高度和圆周不同方位上木材的抗弯强度、抗弯弹性模量、顺纹抗压强度和木材密度的差异,木材密度的径向变异模式和木材力学性质与木材密度的相关关系进行了测定和分析。主要结果是:抗弯强度和抗弯弹性模量在株内不同高度上差异特别显著;顺纹抗压强度和木材密度未表现出显著差异;在圆周不同方位上,三项力学性质和木材密度均为南北向高于东西向,差异不显著;木材密度径向变异模式在不同高度和不同方位上均为接近水平有一定波动的直线;三项力学性质与木材密度的相关关系在不同高度和不同方位上均特别显著,但不同力学性质与木材密度的相关系数有明显差异,不同高度上和圆周不同方位上,亦有差异。 相似文献
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人工林杉木、马尾松木材的断裂特性 总被引:4,自引:0,他引:4
使用扫描电子显微镜观察杉木、马尾松横纹拉应力、顺纹拉应力及冲击载荷作用下的破坏表面,结果表明不同的加载方式、加载速率对木材的断裂过程有影响;木材的微观构造影响其断裂过程。 相似文献
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杉木径面及弦面的木材力学性质的差异 总被引:8,自引:0,他引:8
16个杉木样本的木材力学试验结果表明,除横纹抗压强度外,弦面的抗弯强度和弹性模量、冲击韧性、顺纹抗剪强度及抗劈力均不同程度高于径面。分析了引起差异的原因。 相似文献
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竹节对竹材力学强度影响的研究 总被引:9,自引:2,他引:9
本文对毛竹和刚竹的带节材与不带节竹材的主要力学性质研究表明,带节竹材的抗弯强度、顺纹抗压、抗剪、抗拉强度和冲击韧性都有一定程度降低的趋向,但抗劈开强度和横纹抗拉强度却有明显提高。影响竹材力学强度的主要因素是维管束数量、维管束排列方向及维管束中纤维的力学强度,了解这些规律,对复合材料的结构仿生有重要参考作用。 相似文献
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湿地松与马尾松人工林木材物理力学性质的比较研究 总被引:2,自引:0,他引:2
庄奇 《中南林业调查规划》2004,23(2):58-59
通过对湿地松和马尾松人工林木材物理力学性质的测定和比较分析,结果表明:湿地松人工林木材密度、干缩系数和除冲击韧性以外的力学强度均稍大于马尾松人工林木材,而冲击韧性则恰恰相反.经差异显著性t检验表明:湿地松和马尾松木材物理力学性质指标中顺纹抗压强度、抗弯强度、弦面顺纹抗剪强度和冲击韧性差异极显著,气干密度、基本密度、径面顺纹抗剪强度和端面硬度差异显著,除此之外的其余指标差异不显著. 相似文献
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Influence of Ammoniacal Copper Quaternary treatments on mechanical properties of blue-stained Lodgepole Pine wood 总被引:1,自引:0,他引:1
Three concentrations (2.8%, 2.0%, 1.2%) of Ammoniacal Copper Quaternary (ACQ) was selected to treat Lodgepole pine wood for evaluating ACQ treatment on mechanical properties of blue-stained wood. The bending modules of elasticity (MOE), modules of rupture (MOR), toughness and shearing strength parallel to grain on tangential surface, are tested according to the criteria GB1927-1943-91. Non-treated sample were also tested according to the same procedure. The results showed that the three groups specimen impregnated by different concentrations of ACQ solution met the AWPA standard 2003 of America (UC4A 6.4g/cm^3). There were significant difference of toughness between treated wood and non-treated wood (p=0.01), but there were no statistically significant differences among three concentrations in terms of toughness, and toughness of treated wood was approximately 20% lower than non-treated. MOR, MOE as well as sheafing strength parallel to grain were found to be not significantly different between treated wood and non-treated one, and there were no statistically significant difference among three concentrations of ACQ too. Toughness, MOR, MOE and sheafing strength parallel to grain increased with decrease of concentration of ACQ, but they were hardly affected by ACQ preservatives. 相似文献
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DahurianlarchandMongolianscotchpinearetwomajorconunerciaIconilbroustTeesinDaxing'anlingForesnyArea.Itisob-viousthattbcwoodproPertiesandworkability'ofthetWoplantsarecompletelydifferent.Butlnrecert'years,ltlsfoundthattherearetwodiffer':nttypesinparameterofwood'scolour.phy'sicalandmechanicalproPertiesandwork-ability'inDahurianlarch,namelyredwoodandx"hite..od.l']Andthepropertiesofwhite`voodaresligl1tlyyellow-white,medianweightandhardness,goodinworkability'andLard-ness,goodinwodability'anduneas… 相似文献
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采用杉木和泡桐为试材,对经过KY-FW阻燃剂处理的木材与未经处理的木材进行对比研究,分析KY-FW阻燃剂对木材力学性能的影响.结果表明,木材经KY-FW阻燃剂处理后,除冲击韧性降低外,其它主要力学性能指标(如抗弯强度、顺纹抗压强度及硬度)都有所提高.KY-FW阻燃木材的力学性能达到了一级水基型阻燃剂标准规定的相应指标. 相似文献
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Bamboo is a unidirectional fiber-reinforced bio-composite. Once having cracks, the delaminating propagation is not controlled by the strength but by the interlaminar fracture toughness. In this paper, the behaviors of Mode I (crack opening mode) interlaminar fracture parallel to grain of moso bamboo (Phyllostachys pubescens) were studied. Based on energy theory, the Mode I interlaminar fracture toughness, G IC, was measured using the double cantilever beam specimens, and the fracture surfaces were examined under scanning electron microscope. The results show that: (1) the interlaminar fracture toughness of Mode I is the basic characteristic of bamboo material. The mean value of G IC = 358 J/m2 (coefficient of variation = 16.88%) represents the resistance arresting crack propagation. No significant difference was found for G IC among the specimens located at different heights of the bamboo. (2) Due to the low G IC of bamboo, the crack propagation parallel to grain developed easily. The crack was a self-similar fracture without fiber-bridging. On the fracture surfaces, smooth fibers and plane ground tissue were found at the extended area of Mode I fracture along the longitudinal direction. Under scanning electron microscope, it could be seen that the crack propagation developed along the longitudinal interface between fibers or ground tissue. It indicates that the longitudinal interface strength was weak among bamboo cells. 相似文献