关键词：
木梁;裂纹损伤;碳纤维浆料;抗弯性能;承载力模型
摘 要：
为探索裂纹损伤对实木梁承载性能的影响规律，采用力学试验法研究了预制裂纹木梁的承载性能，并运用碳纤维浆料对木梁裂纹损伤进行了修复探索。结果表明：裂纹深度是裂纹损伤木梁抗弯承载性能削弱的重要影响因素。当裂纹位于木梁两侧中心位置时，裂纹深度为1/9,2/9及1/3截面宽度木梁的抗弯强度及初始刚度相对无损伤木梁分别下降了9%,24%,29%和6.4%,14.7%,26.3%。当裂纹深度为1/3截面宽度时，裂纹深度大，木梁损伤严重，裂纹位于下部时木梁抗弯强度及初始刚度较完好木梁分别下降了44%和39.7%。裂纹深度大会使裂纹位置上下部分木材联系减少，木梁整体协调性减弱，不同裂纹位置木梁极限承载力影响因素多，但差值较小，均在8%以内。采用微尺度碳纤维浆料修复裂纹可大幅改善木梁的裂纹损伤，修复后其抗弯承载性能得到大幅提升，其抗弯强度和初始刚度分别提升了69%和59%,修复木梁破坏模式由裂纹位置剪切破坏转变为较为常见的受弯破坏。推导的裂纹损伤木梁承载力模型所预测的裂纹损伤程度的变化规律与试验结果几乎一致，可用于预测裂纹损伤木梁极限承载力衰减趋势。
译 名：
Flexural bearing capacity of crack damaged solid wood beams
作 者：
BAI Xinchun;YANG Xiaojun;TAN Yongjie;LIU Jiamin;WANG Chaojie;College of Materials Science and Engineering, Nanjing Forestry University;
关键词：
wood beam;;crack damage;;carbon fiber slurry paste;;bending resistance;;bearing capacity model
摘 要：
In order to explore the influence law of crack damage on the load-bearing pe-rformance of solid wood beams, this study used the mechanical test method to investigate the load-bearing performance of prefabricated cracked wood beams and explored the repair of crack damage of wood beams using the carbon fiber slurry. The results showed that the crack depth and distribution position were important factors influencing the weakening of the flexural load-bearing pe-rformance of crack damaged wooden beams. When the cracks were located at the center of both sides of the beam, the flexural strength and initial stiffness of the beams with crack depths of 1/9, 2/9 and 1/3 cross-sectional width decreases of 9%, 24%, 29%, and 6.4%, 14.7%, 26.3%, respectively, compared with the undamaged beams. When the crack depth was 1/3 section width, the crack damage located in the lower part had the greatest effect on the load-bearing pe-rformance of the wood beam, followed by the crack located in the upper part, and the crack located in the middle part had the least effect. When the crack depth was 1/3 cross-sectional width, the damage of the beam was serious and the crack depth was large. The flexural strength and initial stiffness of the beam were decreased by 44% and 39.7%, respe-ctively, when the crack was located in the lower part of the beam compared with the intact beam. The crack depth would reduce the connection between the upper and lower parts of the wood at the crack location, and the overall coordination of the beam was weakened. The ultimate bearing capacity of the beam at different crack positions was affected by many factors, but the difference was small, being all within 8%. The use of micro-scale carbon fiber slurry to repair cracks could significantly improve the crack damage of wood beams, and their flexural load-bearing performance was greatly improved after the repair. Their flexural strength and initial stiffness were increased by 69% and 59%, respectively, and the damage mode of repaired wood beams was changed from shear damage at the crack location to the more common damage by bending. The variation pattern of the crack damage degree predicted by the derived crack damage wood beam bearing capacity model was almost consistent with the experimental results, being able to be used to predict the decay trend of the ultimate bearing capacity of crack damaged wood beams.
