【作者】 张晓敏；

【导师】 王喜明； 孙正军；

【作者基本信息】 内蒙古农业大学 ， 木材科学与技术， 2010， 硕士

【摘要】 本论文针对风电叶片翼梁用竹木复合材料在冷压热固化中的流变模型而展开,对杨木、竹材横纹压缩的流变行为均进行了研究和评价,还对杨木单板层积材,竹木复合单板层积材的压制工艺、树脂浸渍量、最优压力等方面进行了研究。研究结果表明:(1)杨木径向压缩粘弹性行为以不同厚度杨木单板为原料,探讨不同因素对杨木单板应力松弛行为的影响。实验结果表明:室温,变形相同时,含水率越大,应力松弛量越大;绝干材随着温度升高,应力松弛量略有增加,但没有含水率的影响显著;绝干材在变形相同时,有胶比无胶的应力松弛量大。杨木单板的应力松弛行为可以用由Maxwell模型和弹簧并联组成的三元件模型来模拟。(2)竹材径向压缩蠕变行为探讨了毛竹在恒定压力下与不同温度、含水率的关系,确定出其对应的蠕变模型,同时研究了带节竹材蠕变性能的影响。结果表明:在压应力小于屈服极限时,所选用的Burger模型可以用来模拟竹材径向压缩的短期蠕变行为;四元件参数值均随着温度和含水率的增加而减小;竹材带节后其蠕变黏性变形量增大。(3)杨木层积材尺寸稳定性、树脂浸渍量及流变学用不同因素制备浸胶杨木单板层积材。主要分析了影响单板层积材尺寸稳定性的因素,并分析了影响应力松弛及尺寸稳定性的因素。结果表明,压力和温度对杨木单板层积材尺寸稳定性影响最为显著,结合应力松弛及尺寸稳定性分析可以得出制备单板层积材的最优工艺,同时以浸渍环氧胶的杨木单板为原料制备单板层积材(LVL)。分别探讨杨木单板在不同固含量的环氧树脂中,浸渍不同时间的浸渍量,不同浸渍量对LVL应力松弛行为、2hTS和顺纹抗压强度的影响。结果表明:①当环氧浸渍液的固含量相同时,随着浸渍时间的延长,杨木单板的树脂浸渍量逐渐增加,而后趋于稳定;②在相同的浸渍时间内,杨木单板在较高固含量的环氧浸渍液中的树脂浸渍量均高于低固含量的环氧浸渍液:③随着LVL板中含胶量的增加,杨木LVL的密度和顺纹抗压强度均为先增加后稳定;2hTS则为先减小后稳定;④在本试验范围内,杨木单板在压力为2、4、6MPa下的最优浸渍量均为50%。(4)竹木复合在冷压热固化中最佳压力选择以浸渍环氧胶的杨木单板和分级竹片为原料制备竹木复合单板层积材(LVL)。探讨了不同压力对LVL的影响,测试了竹木组坯方式为4竹5木下实验不同压力LVL的物理力学值,得到在本实验竹木组坯方式下,最优的压力范围为3～5MPa。更多还原

【Abstract】 Bamboo/wood preservation is an important issue of current wood industrial development. In this paper, for the wind blade spar with bamboo and wood composite materials in cold thermal curing of the rheological model and the start of this paper to the poplar, bamboo stripes and rheological behavior of compression were carried out research and evaluation, but also on the Poplar veneer Laminated wood, bamboo and wood composite LVL suppression techniques, the amount of resin impregnation, the optimal pressure, etc. were studied. The results are as follows:(1) Viscoelastic Behavior of poplar under radical compressionA study on the different thickness of Poplar (Populus nigra) veneer. The effects of the different strain levels、temperature、moisture content and the adhesive on stress relaxation of poplar veneer were explored. The results showed that: 25±2 degree,under the same deformation, The amount of Stress relaxation in proportional to Moisture Content ;0% Moisture Content, As the temperature increases, The amount of Stress relaxation increase slightly;0% moisture content,under the same deformation,Poplar veneer with adhesive have a greater amount of Stress relaxation,And the Stress relaxation of poplar veneer behavior can be used by the Maxwell model and spring model composed of three components to simulate.(2) Creep behavior of bamboo under radical compressionDiscussed the bamboo (Phyllostachs edulis) under a constant pressure with different temperatures、different moisture content relationship, Identified the corresponding creep model, also studied bamboo with node compression creep performance. The results showed that: Under the compressive stress less than the yield limits, Burger model can be used to simulate bamboo radial compression of the short-term creep behavior; The four–element model parameters were as the temperature and the Moisture content decreased. Bamboo node creep results showed that the bamboo with node permanent creep deformation increases.(3) The analysis for Poplar LVL Dimensional stability、Resin impregnation and RheologyUse different way prepare Poplar LVL. Mainly analyzes the factors that impact LVL dimensional stability,and analysis the factors that impact stress relaxation and dimensional stability. The results show that pressure and temperature on Poplar LVL dimensional stability of the most significant.And strengthened laminated veneer lumber (LVL). was manufactured using Poplar(Populus nigra) veneer as raw materials, Poplar veneer were impregnated in epoxy resins with different solid contents, and then to calculate the amounts of resin impregnation with different time durations; The effects of the impregnation amount on LVL stress relaxation、2hTS and longitudinal compressive strength were also explored. The results showed that :(1) When the solid contents of the epoxy resin were the same, the impregnation increment of the Poplar veneer increased with the impregnation time and then became stable;(2) When the impregnation time durations were the same, the impregnation increments of the Poplar veneer impregnated in epoxy resin with higher solid contents were higher than those in epoxy resin with lower solid contents;(3) AS the impregnation increment increased, The density of Poplar LVL and longitudinal compressive strength increased and then stabilized, 2hTS decreased and then stabilized.(4) Within the scope of the experiment, Poplar veneer were impregnated in epoxy resins with solid content of 55%>5h,LVL can reach better requirement. (4)The optimal pressure of Bamboo/wood composite under Cold compression and Thermal curingStrengthened laminated veneer lumber (LVL) was manufactured using Poplar (Populus nigra) veneer and bamboo as raw materials, Explored the impact of different pressures on the LVL,When the Assembly patterns is 4, 5 Bamboo Wood,The density of LVL、2h TS、longitudinal compressive strength on properties of the bamboo/wood composite LVL were explored, Under the experimental conditions , The Optimal pressure range is 3~5MPa.更多还原