【作者】 范玉凯；

【导师】 朱一辛；

【作者基本信息】 南京林业大学 ， 木材科学与技术， 2007， 硕士

【摘要】 本课题提出了一种新的预应力竹木复合材料制造方法,将竹束加捻形成的预应力应用于竹木复合单板层积材。通过对竹束的性能的评价分析,找出适合加捻的竹束制造方法,再对竹束进行不同方法的加捻制造出竹束增强层,在得出优化的增强层的基础上,进一步拓展至竹束加捻复合单板层积材的研制及分析,从而验证竹束加捻所形成的预应力对竹木复合单板层积材的增强效应。试验研究包括了三个部分:竹束制作的研究;增强层中竹束加捻方法的研究与选择;竹木复合单板层积材的制作。试验选用了四种竹材软化方法,依据竹束的细度和竹丝的抗拉强度两项指标分析了不同的软化处理方法对制得竹束的影响,分析得出竹材在水中浸泡两天是较好的软化方式。经过这种方式软化的竹材,滚压时可以得到分离程度较好且力学性能也较好的竹束。试验制作了四种不同结构形式的增强层,通过力学性能的测试结果可以得出,竹束单股加捻形成的预应力显著提高了竹木复合材料的力学性能。含单股加捻竹束的增强层与含不加捻竹束的增强层的数据对比显示,加捻预应力对弹性模量和静曲强度的贡献率分别达到了17.46%和11.11%,验证了课题提出的预应力应用于竹木复合单板层积材可以增强力学性能的设想。测试结果也表明增强层中竹束的存在与否及竹束是否加捻与剪切强度的大小无明显关联。同时试验也对竹束加捻形成的预应力进行了理论分析。试验制作了五种不同结构形式的竹木复合单板层积材,通过对测试结果的数据分析得出,含竹束单板层积材与不含竹束的单板层积材相比弹性模量和静曲强度都较高;含竹束量相同的单板层积材,竹束经过加捻的单板层积材弹性模量和静曲强度都较高,表明竹束单股加捻形成的预应力效用显著,同时也可看出预应力对于静曲强度的增强效应小于其对弹性模量的增强效应;随着竹束含量的提高,含加捻竹束单板层积材的力学性能呈上升趋势。研究结果表明竹束的存在与否及竹束是否加捻与剪切强度和冲击韧性无明显关联。更多还原

【Abstract】 This topic proposed one new research technique of wood and bamboo composite, in which we apply the pre-stressed from twisted bamboo ties into wood and bamboo composite. The experimental study included three parts: the manufacture research of bamboo ties; the research and choice of the method of twisting bamboo ties in reinforcement board; the manufacture method of wood and bamboo composite.The bamboo ties were manufactured by suppressing the softened bamboo with rolling-suppress machine. In the experiment we selected four kind of softening method of bamboo. According to the degree of fineness and the mechanics property of bamboo, we analyzed the influence of different softening method to the bamboo ties. The result indicated soaking bamboo in the water two days is the better softening method. This kind of bamboo ties had a better degree of fineness and a better mechanics performance.In the experiment we manufactured four kind of reinforcement board. The test result indicated the pre-stressed from the twisted single strand of bamboo ties remarkably reinforced the mechanics performance of composite material. The data contrast between the reinforcement board containing single strand of bamboo ties and the reinforcement board which contained bamboo not being twisted demonstrated that the contribution ratio of pre-stressed had respectively achieved to 7.46% and 11.11% in Modulus of Elasticity (MOE) and Modulus of Rupture (MOR) which confirmed applying pre-stressed into wood and bamboo composite may reinforce mechanics performance. Meanwhile, the result indicated whether the existence or not of bamboo ties didn’t connect with the Shearing Rupture. In the experiment we established the mechanics model of twisted bamboo ties and analyzed it theoretically.In the experiment we manufactured five kind of LVL. The data analysis indicated: because of the reinforcement of bamboo ties, both MOE and MOR of LVL not containing bamboo ties were lower than the MOE and MOR of LVL containing bamboo ties respectively; when the LVL containing the same quantity bamboo ties, both MOE and MOR of the LVL containing twisted bamboo ties were higher, which proved the effectiveness of pre-stressed form the twisted single strand of bamboo ties was remarkable; with the quantity of bamboo ties increasing, the mechanics performance of the LVL containing twisted bamboo ties reinforced. The test result showed that whether the existence or not of bamboo ties or whether bamboo ties were twisted didn’t connect with the Shearing Rupture and Impact Toughness of the LVL.更多还原