共查询到20条相似文献,搜索用时 31 毫秒
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Until now we developed an estimation method for strength distributions of laminated veneer lumber (LVL) element by nonlinear least-squares method (NLM). Estimated strengths by this method were modulus of elasticity (MOE) and modulus of rupture (MOR) in the horizontal use direction and the vertical use direction, tensile strength and compression strength. But to use LVL for structural members, shear strength was also needed. Therefore, we tried to estimate the shear strength distribution of LVL element by NLM same as MOE and MOR in the horizontal use direction and the vertical use direction, the tensile strength of LVL and the compression strength of LVL in the previous reports. We conducted shear strength test for LVL and estimated element shear strength distribution by LVL strength data in the horizontal and vertical use direction. Next, we simulated LVL shear strength distribution using element shear strength distribution and compared with experimental ones in each use direction. They were overlapped in both use direction. Therefore, we could validate NLM for estimating element shear strength distribution. 相似文献
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以杨木单板和竹帘为原料,采用低分子量水溶性酚醛树脂浸渍处理,通过干燥、组坯、热压等工艺制备竹木复合强化单板层积材。探讨了组坯方式、压缩率、热压温度、热压时间4个因素对竹木复合强化单板层积材弹性模量(MOE)和静曲强度(MOR)的影响。结果表明:表层为一层竹帘的竹木复合强化单板层积材的MOE和MOR较大,分别是13.43GPa、148.13MPa,与表层为杨木单板次表层为竹帘组坯方式相比分别增加了33.63%、56.16%。确定了竹木复合强化单板层积材较合理的制造工艺参数。 相似文献
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《中国林业科技(英文版)》2010,(2):68-72
Factors influencing bonding strength of laminated bamboo strips lumber (LBSL) were investigated in this paper. In order to find an optimized technology, this paper investigated how the thickness of bamboo strips, the assembly orientation of bamboo curtain, the type of adhesives, as well as coupling agent treatment of bamboo curtain affected the bonding strength. The following conclusions were drawn: 1)The thinner the thickness of the bamboo strips, the bigger the bonding strength of LBSL; 2) The assembly or... 相似文献
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丛生竹物理力学性能及其对制造竹建筑材料的影响 总被引:8,自引:0,他引:8
研究了两种最重要的丛生竹种云南黄竹和龙竹的物理和化学性能。实验结果表明,黄竹的物理性能,如纵横干缩性等优于龙竹,而且黄竹的力学性能如静曲强度、静曲弹性模量及顺纹压缩与剪切强度也比龙竹高。与建筑用木材相比,两种丛生竹的物理力学性能均达到了建筑材料的性能要求。 相似文献
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WANG Zheng GUO WenjingResearch Institute of Wood Industry Chinese Academy of Forestry 《中国林业科技(英文版)》2004,3(1):74-79
Bambooisoneofimportantreproduciblefast-growingforestresources.Itisattributedtoitsrapidgrowthrateandhighyield,andcanbeoflong-termutilizationwithonlyonceplantationandreasonablemanagement.Comparedwithwood,bamboohasgoodstrength,elasticityandhighstiffness.ForalongtimeitisusedasoneofimportantstructuralmaterialsinChinaandothercountriesinbamboo-producedregionsoftheworld.Intraditionalbamboostructuralutilization,thebamboologsareuseddirectly.Butasthelargevariationindiameterandcharacter,theyareusedonlyin… 相似文献
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广宁县竹香骨下脚料制备竹碎料刨花板及其复合改性研究 总被引:1,自引:0,他引:1
采用竹香骨下脚料为原料,以脲醛树脂和三聚氰胺改性脲醛树脂胶粘剂制备竹碎料刨花板,并与木纤维复合改性,检测并分析了内结合强度、静曲强度、弹性模量和吸水性。结果表明,在热压温度为160℃时,竹碎料板和竹木复合碎料板的物理力学性能均满足国标规定在干燥状态下使用的普通用板要求。当木纤维与竹碎料复合后,复合板材的静曲强度和弹性模量有一定程度提高,但内结合强度降低。 相似文献
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以重组竹、竹束单板层积材(BLVL)、竹集成材为代表的竹质工程材料受到越来越多的关注和应用。文中采用超声波法、自由横向振动法和力学法分别对上述3种典型竹质工程材料的纵向动态弹性模量(MOE)进行评价比较,结果表明,横向自由振动法能较为快速、准确和无损地评价出竹质工程材料的MOE,MOE的变异系数与其自身铺装结构有关;重组竹、BLVL和竹集成材的一阶共振频率分别为455.73、380.41和487.62 Hz;超声波在竹集成材的纵向上传播速度最快,重组竹其次,BLVL最慢;三点弯曲力学测试发现3种竹质工程材料的断裂模式不同,全顺向的重组竹为竹纤维拉断和界面剪切破坏,纵横组坯的BLVL为横向竹束拉断以及竹/木复合界面分层,而更多体现实竹性能的竹集成材为底层竹材维管束拉断和拔出破坏,其断裂载荷为重组竹> BLVL >竹集成材,而断裂位移为竹集成材> BLVL >重组竹。 相似文献
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杉木积成材竹片贴面工艺探讨 总被引:1,自引:0,他引:1
杜春贵 《林业机械与木工设备》2003,31(12):35-36,39
对杉木积成材进行了竹片贴面的初步试验,结果表明:杉木积成材进行竹片贴面切实可行;竹片贴面后的杉木积成材密腹略高于基材;竹片与基材之间的胶合强度大于基材内部的胶合强度;贴面板的MOR和MOE高于基材:24h吸水厚度膨胀率佟明显低于基材。 相似文献
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The objective of this study was to investigate the physical and mechanical performance of flakeboard reinforced with bamboo strips. The study investigated three different bamboo strip alignment patterns and an experimental control. All panels were tested in static bending both along parallel and perpendicular to the lengths of the bamboo strips. Internal bond strength (IB), thickness swelling (TS), linear expansion (LE), and water absorption (WA) were also examined. As expected, modulus of rupture (MOR) and modulus of elasticity (MOE) were substantially greater for all three experimental panel types as compared to the control group. LE was also improved for all three experimental panel groups. The bamboo strip alignment patterns had no significant effect on TS, WA and IB. The sample means for MOR, MOE and LE tested perpendicular to the bamboo strip lengths yielded slightly lower mean values than corresponding samples tested parallel to the bamboo strips lengths. This difference in mechanical properties is largely attributed to low panel density in the failure zones. 相似文献
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竹材刨花板热压工艺的研究 总被引:1,自引:0,他引:1
利用正交试验法研究了竹材刨花板热压曲线中各因素与极材的静曲强度,弹性模量及平面抗拉强度间的关系。结果表明,第一阶段压力是影响竹材刨花板力学性能的最主要因素,热压温度及采一阶段时间对力学性能也有较大的影响。根据试验结果确定竹材刨花板的最佳热压工艺参数。 相似文献
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为了探索较佳的木束条尺寸,以提高杉木积成材的质量,研究了不同尺寸的杉木木束条对杉木积成材性能的影响规律,结果表明:木束条的长度对杉木积成材的纵向静曲强度、弹性模量、24h吸水厚度膨胀率有较大的影响;木束条的厚度对杉木积成材纵向静曲强度、弹性模量的影响不大,但对24h吸水厚度膨胀率、内结合强度有较大的影响;木束条的宽度对杉木积成材的物理力学性能影响极小,不存在统计意义上的影响;木束条的较佳尺寸为:长度120 mm,宽度4mm,厚度2.5 mm. 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