多重荷载下意杨旋切板胶合木新型楼盖受力性能

Poplar Laminated Veneer Lumber (hereafter referred to LVL) is made of a kind of fast-growing lumber, which is of high reliability, small variability and abundant supplies. It will have a good application prospect in construction engineering. The project researches deeply into the damage mechanism of LVL poplar and the force mechanism of LVL box floor, to determine the evolution mechanism of the macro mechanical property caused by the micro damage development of the components. Firstly, the physical and mechanical properties of poplar LVL and the along and perpendicular to grain fracture stress intensity factor Kic is achieved through experiment, and the relationship between Kic and strain energy release rate is analyzed. Secondly, the damage mechanism, flexural strength, flexural stiffness, creep of poplar LVL box floor under short-term and long-term load are analyzed, the self-vibration frequency performance of the box floor is also achieved under dynamic load. The effect of rib spacing, the height and width of rib as well as the connection joints on floor bending performance are well-considered. Thirdly, ABAQUS is used to build a fine numerical model of LVL poplar box floor and the results of the analysis with the test results are compared and verified. Finally, the means data processing, the theory of damage of composite materials and Hoff type composite sandwich plate are combined together to establish the analysis theory of poplar LVL box floor. The research results of the project will reveal the stress essence of poplar LVL box floor, and develop the application of polar LVL material to construction, as well as provide technological support and theoretical basis for the application of poplar LVL floor system to wood structure in China.

意杨旋切板胶合木（简称意杨LVL）是一种可靠性高、变异性小的工程材料，它由资源丰富的速生杨木重组而成，有良好的建筑工程应用前景。项目拟对意杨LVL新型箱型楼盖（简称新型楼盖）受力性能进行探索研究，确定材料微观损伤发展致使宏观受力性能劣化的演变机制。主要研究内容：意杨LVL材料物理力学性能及顺、横纹理断裂应力强度因子Kic及其与应变能释放率间关系；新型楼盖在多重荷载下损伤发展机理、受弯刚度和承载力、蠕变及自振频率等性能，分析新型楼盖节点连接方式及肋梁间距、尺寸改变对其受力性能的影响；应用ABAQUS建立新型楼盖精细化数值模型并将分析结果与试验结果比较验证；采用数据处理、复合材料损伤、Hoff型夹层板理论和试验研究相结合的研究手段，揭示新型楼盖在多重荷载下强度变形规律，确定关键参数，建立分析理论。研究成果将阐释新型楼盖的受力本质，为推动适合我国国情的木结构楼盖体系提供理论依据和技术支撑。

意杨旋切板胶合木（意杨LVL）可靠性高、变异性小，是有良好应用前景的工程木。按照材料→构件→体系的研究顺序，首先对意杨LVL进行材性试验，确定意杨LVL的含水率、抗压、抗拉强度以及抗弯弹性模量和抗弯强度等物理力学参数，明确其本构关系。其次对3种形式意杨LVL正交肋梁节点的9个试件进行受力性能试验及理论与数值分析，确定其破坏模式、刚度及极限承载力，并将性能最优的节点用于后期研究中。再次对5个3.6×4.8m的意杨LVL正交肋梁系试件及1个同尺寸传统形式肋梁系试件进行受弯性能试验、理论及有限元分析，确定其双向抗弯刚度、荷载-应变关系及荷载-挠度关系等，研究肋梁高跨比、间距等对楼盖受力性能的影响。接着对4个意杨LVL正交肋梁系及4个正交肋梁箱型楼盖进行局部和整体荷载下的受弯性能试验及理论与数值分析，得到其抗弯刚度、荷载-挠度关系以及各构件的荷载-应变关系，探究高跨比、肋梁间距和OSB板厚度对楼盖受弯性能的影响。随后通过4个箱型楼盖的长期加载试验，研究局部损伤、重复加载及不同荷载值和环境温湿度等因素对楼盖蠕变性能的影响。然后通过意杨LVL正交肋梁楼盖试件的自由振动试验，获得其基本自振频率及阻尼比；通过人致振动试验得到多种工况下各试件的峰值加速度及加速度振级，探究肋梁高度、短边肋梁间距、OSB板厚度及不同类别人致振动荷载对箱型楼盖振动响应的影响，并利用自振频率进行舒适度评价。最后采用双向板法、拟板法和交叉梁系法等三种方法对意杨LVL正交肋梁箱型楼盖进行理论计算，结果表明拟板法的分析结果与试验数据吻合良好；建立了意杨LVL箱型楼盖的修正Burger蠕变分析模型及基本自振频率和人致振动下峰值加速度计算方法，计算结果均切合试验数据。综上研究表明，意杨LVL正交肋梁箱型楼盖具有整体性好、刚度大、承载力高及使用舒适等特点，成果可为推动适合我国国情的木结构楼盖体系的发展应用提供理论依据和技术支撑。