有胶缝缺陷的胶合木梁受弯性能试验研究

发布时间：2019-01-01 16:22

【摘要】：胶合木结构具有结构性能优良、抗震性强、节能效应显著、建造方便等优点,并且满足我国“绿色建筑、建筑工业化”的重大需求,逐渐受到人们的青睐。其胶合界面,即同时包含木材细胞壁和胶粘剂的区域,是应力应变传递的必经通道,是决定材料使用强度、使用寿命的关键因素,在复合材料整体性能中起着非常关键的作用。论文基于国产速生材兴安落叶松,通过人为模拟胶合界面缺陷,制作了含单、双层胶缝缺陷和胶合完好3组胶合木梁试件,研究其受弯性能。主要研究内容与成果如下:1.首先对人工模拟的胶缝缺陷进行超声波实测研究,采用PSD-V-A综合判别法分析胶缝缺陷位置、长度及严重程度,并与预设的缺陷位置进行对照,确定胶缝缺陷的真实情况,为下一步试验提供参考依据,同时验证超声波法测试胶缝缺陷的可行性。2.采用振动法测试了 5层落叶松胶合木梁的弹性模量,并与静力试验法所测试验结果进行对比分析。通过探讨两种方法测试结果间的相关程度,来分析简支条件下横向振动法测试胶合木简支梁抗弯弹性模量的准确性。3.对胶合木梁进行静力弯曲破坏试验,通过对含有不同胶缝缺陷胶合木梁的挠度、应变、承载能力等实测数据的分析对比,及试件破坏形态和破坏机理的观察和分析,研究带有不同胶缝缺陷胶合木梁的受弯性能,得到了胶缝缺陷对胶合木梁抗弯性能的影响规律。4.采用ANSYS有限元分析软件建立与试验对应的胶合木梁模型,分析了相同荷载作用下,每组试件的跨中挠度、应力应变、胶缝处层板间隙变化等,通过挠度和应变数值的对比,分析了胶缝缺陷对胶合木梁的影响,同时与试验测试结果进行对照,验证试验分析结果的正确性。
[Abstract]:The glued wood structure has the advantages of excellent structure performance, strong seismic resistance, remarkable energy saving effect, convenient construction and so on, and meets the great demand of "green building, building industrialization" in our country, and has been gradually favored by people. The bonding interface, which contains both wood cell wall and adhesive, is a necessary channel for stress and strain transfer, and a key factor to determine the strength and service life of the material, which plays a very important role in the overall properties of the composite. In this paper, based on the domestic fast growing wood Larix gmelinii, three groups of glued wood beams were made by artificial simulation of bonding interface defects, including single and double layers of glued joints and intact glued wood beams, and their bending properties were studied. The main contents and results are as follows: 1. First of all, the ultrasonic testing of the artificial seam defects is carried out, and the PSD-V-A comprehensive discriminant method is used to analyze the position, length and severity of the joint defects, and compared with the preset defect positions to determine the true situation of the glue joint defects. To provide the reference for the next test, and to verify the feasibility of ultrasonic testing glue joint defects. 2. The elastic modulus of 5 layers of Larix gmelini beams was measured by vibration method, and the results were compared with those measured by static test method. By discussing the correlation degree between the test results of the two methods, the accuracy of measuring the flexural elastic modulus of glued wood simply supported beams by transverse vibration method under simply supported condition is analyzed. 3. The static bending failure test of glued wood beams was carried out. Through the analysis and comparison of the measured data of deflection, strain and bearing capacity of glued wood beams with different joint defects, the failure pattern and failure mechanism of the specimens were observed and analyzed. The flexural behavior of glued wood beams with different joint defects is studied and the influence of adhesive joint defects on the flexural properties of glued wood beams is obtained. 4. ANSYS finite element analysis software was used to establish the model of glued wood beam corresponding to the test. Under the same load, the mid-span deflection, stress and strain of each set of specimens, and the change of laminate gap at the glue joint were analyzed. The deflection and strain values were compared. The influence of glue joint defects on glued wood beams was analyzed and compared with the test results to verify the correctness of the test results.
【学位授予单位】：中南林业科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU366.3

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