共查询到19条相似文献,搜索用时 562 毫秒
1.
2.
由于受木段长度、旋切机等因素的限制,为了使单板层积材满足实际使用的要求,单板必须纵向接长。本文研究了对接、斜接两种单板接头形式及其分布形态对单板层积材静曲强度(MOR_F)和静曲弹性模量(MOE_F)的影响。 相似文献
3.
4.
杨木单板的湿热处理规律以及对杨木单板层积材性能影响的研究结果表明,单板湿热处理后产生了塑化,形成了一部分不可恢复的变形,密度平均增加了38.7%;对抗拉强度的影响不显著;对单板压缩率和膨胀率有着特别显著的影响,单板平均压缩了27.8%,经24h水浸泡,单板恢复膨胀仅18.7%.单板湿热处理后经过低压压制,可以得到与高压压制相同密度的板材,且板材的断面密度差异小,水平剪切强度提高了27.1%,静曲强度增加了17.8%,弹性模量没有显著变化,吸水厚度膨胀率降低了约10个百分点. 相似文献
5.
采用响应面法(RSM),研究了单板厚度和涂胶量对桉木单板层积材(L、几)力学性能的影响。结果表明:单板厚度和涂胶量对桉木LVL的垂直加载和平行加载条件下的静曲强度(MOR┷、MOR//)和弹性模量(MOE┷、/dOE//)有显著影响。实验值与预测值的决定系数为0.72,0.79,0.59,0.69。本研究所获最佳工艺条件为:单板厚度2.0啪,涂胶量233g·m^-2在此工艺条件下压制的桉木单板层积材垂直加载条件下的静曲强度(MORJ和弹性模量(MOE上)分别为85MPa与15118MPa,平行加载条件下的静曲强度(MOR//)和弹性模量(MOE//)分别为87MPa与15288MPa,回归模型的预测值与实验值的相对误差最大为9%,最小为3%。实验产品的MOR和MOE分别达到结构用单板层积材国家标准的优等品和140E级别。 相似文献
6.
7.
玻璃纤维增强结构用单板层积材热压工艺研究 总被引:1,自引:0,他引:1
通过玻璃纤维增强速生杨木制备杨木单板层积材(LVL),可提高杨木的强度等级,使其达到结构集成材层板的使用要求。采用正交实验方法,研究温度、时间、压力、偶联剂浓度、涂胶量对杨木单板层积材弹性模量、静曲强度、剪切强度的影响,其中主要研究热压工艺对力学强度的影响,得出的最优工艺参数为:热压温度130℃、时间100s/mm、压力1.2MPa。 相似文献
8.
9.
采用低分子量酚醛树脂制备杨木单板层积材,对该产品的静曲强度影响因子进行分析。结果表明:PF树脂的浓度和单板的压缩率对低分子量PF型杨木单板层积材的静曲强度影响显著;酚醛树脂浸渍杨木单板后提升了单板本身的MOR,这对增强杨木单板层积材的MOR起到了促进作用;MOR平均值随着压缩率的增加而提高,25%和35%两个压缩率水平对MOR平均值的影响差别很大,而15%和25%两个压缩率水平对MOR平均值的影响差别较小。 相似文献
10.
不同结构杨木单板层积材的蠕变和抗弯性能 总被引:17,自引:1,他引:17
本文研究了单板层积材(LVL)的压缩率、结构形式和增强方式对其蠕变特性、弹性模量以及静曲强度的影响。研究表明:在本研究范围内,提高LVL的密度和合理组坯是改善其力学性能和蠕变特性的较好途径;采用浸胶单板可适当改善LVL的力学性能;LVL的蠕变特性曲线同木材的相似,但其瞬时挠度一般大于瞬时弹性恢复值;通过提高LVL的静曲强度和弹性模量有望改善其蠕变性能。 相似文献
11.
Mikael Fonselius 《Wood Science and Technology》1997,31(6):399-413
Summary The effect of size on bending strength has been experimentally determined for laminated veneer lumber. Width was found to have no effect on bending strength. The effect of depth times length on bending strength obtained by the slope method was about 0.075, which is in good agreement with the results obtained by the shape parameter method. The effect of length is somewhat more severe than the effect of depth. Size was found to have no effect on modulus of elasticity or modulus of rigidity.In addition, the relationships between bending strength, modulus of elasticity and density of laminated veneer lumber were experimentally modelled.The author is pleased to acknowledge Research and Development Manager Matti Kairi, who represents the Kerto laminated veneer lumber manufacturer of Finnforest Oy, for fruitful co-operation over several years. The patience of senior research scientist Markku Kortesmaa, who calculated and several times explained the details of Appendix A for the author, is also acknowledged 相似文献
12.
对福建省主要桉树木材材性及其旋切单板厚度偏差、背面裂隙率进行检测分析,探讨木材旋切单板的适应性和制造胶合板的工艺并采用正交法优选最佳工艺参数。结果表明:尾叶桉单板背面裂隙率和单板厚度变动系数比尾巨桉小,尾叶桉用于旋切1.5 mm厚度单板质量较佳。尾叶桉木材制造胶合板较佳工艺参数:热压温度为130℃、单位压力为1.4 MPa、热压时间为1.35 min·mm-1、涂胶量为320 g·m-2。工艺条件对板材性能均有影响,桉树木材龄级对板材性能影响显著,随着桉树龄级的增大,板材性能有较大幅度提高,特别是静曲强度、弹性模量影响最为明显。 相似文献
13.
14.
WangShujuan LuZhenyou LiNing SunYanling 《中国林学(英文版)》2003,5(3):39-41
The stress-strain relation of laminated veneer lumber (LVL) was established by the method of regression, and its constitutive equation at large deformation and constant loading conditions was given to predict the static mechanical behaviors of LVL. 相似文献
15.
圆筒形单板层积材(简称圆筒LVL)是一种新型木质工程材料,它是以螺旋缠绕的方式将单板加工成交错层积的构造,从而抑制弹性模量的下降。圆筒LVL具有很好的力学性能和优良的工程性能,可广泛应用于建筑等领域。本文就圆筒LVL的制造方法、研究状况、特点及用途等进行了较为详细的归纳总结。 相似文献
16.
17.
Zephyr strand board (ZSB) and zephyr strand lumber (ZSL) were produced using zephyr made from poplar veneer to investigate the greater utilization of low-density poplar as a structural material. These materials were then compared to ordinary plywood, laminated veneer lumber (LVL) from poplar veneer, lauan plywood, and particleboard. The bending properties (moduli of rupture and elasticity) of ZSB proved superior to those of poplar plywood: and ZSL produced from poplar veneer zephyr had bending properties greater than ordinary LVL from poplar veneer. Apparently, the conversion of the poplar veneer into zephyr material had a positive effect on bending properties. Additionally, poplar ZSB had bending properties superior to those of lauan particleboard and equal to those of lauan plywood. The internal bond strength of poplar veneer ZSB was nearly two times greater than that of lauan particleboard.Parts of this report were presented at the international symposium on the utilization of fast-growing trees, Nanjing, China, October 1994. Report IV appeared inMokuzai Kogyo 49:599, 1994 相似文献
18.
介绍了用β射线对单板密度进行检测实验,重点研究了木材厚度和β射线透射时间对单板密度检测结果的影响,并对其进行分析,得出了将β射线检测法用于单板密度的在线、无损自动检测上的应用条件. 相似文献