【摘要】 以同一批次旋切杨木单板为试验对象，设计船形、菱形、锯齿形、双圆形、蝶形5种补片(为与仿真试验进行对比，试验单板及补片的尺寸均依据相关标准及仿真尺寸进行设计),用环氧树脂胶黏剂进行粘贴，制备静态拉伸试验试件；按照国家标准GB/T 36408—2018《木结构用单板层积材》、GB/T 14017—2009《木材横纹抗拉强度实验方法》,应用济南试金WDW-300E微机控制电子式万能试验机，对5种补片每组设置的20个单板试样进行木材顺纹抗拉试验，测定补片修补单板断裂应力值、应用扫描电子显微镜观测补片修补单板断裂的微观形态。应用数值模拟方法，依据汉克森(Hankinson)失效理论，对设计的5种补片形状的修补单板仿真模型进行拉伸模拟试验，计算5种不同补片形状修补单板仿真模型的断裂失效应力值。对比实测与仿真试验结果，检验仿真的有效性，分析木质单板缺陷挖补技术中补片形状对修补的木质单板力学性能的影响及单板的断裂模式。结果表明：(1)5种补片中，除菱形补片外，其余单板的失效单元均沿45°方向延伸，在电镜观测下试样断裂位置显示有多处细胞壁发生断裂，这些细胞与板壁的断裂细胞壁相连形成了宏观裂缝。(2)在数值模拟与实测中，蝶形、菱形补片修补后单板的承载能力均较大，其失效载荷值分别为31.3、29.7 MPa;菱形、锯齿形、双圆形、蝶形4种形状的补片，比船形补片的承载能力提升了25.52%～30.18%;蝶形补片的承载能力最大且与节子形状契合度最高。(3)仿真与实测，差值均在12.1%以内，验证了仿真的可行性。更多还原

【Abstract】 Using the same batch of rotary-cut poplar veneer as the test veneer, five kinds of patches were designed: boat-shaped, diamond-shaped, serrated, double round and butterfly-shaped(for comparison with the simulation test, the dimensions of the test veneer and the patches were designed according to the relevant standards and simulation dimensions), pasted with epoxy resin adhesive, and prepared static tensile test specimens; in accordance with the national standard GB/T 36408 and GB/T 14017-2009 “Wood cross-grain tensile strength test method”, 20 veneer specimens of each group of 5 kinds of patches were tested by applying Jinan WDW-300E microcomputer-controlled electronic universal testing machine to determine the tensile strength of the patches. The stress values of the fracture of the patched veneer were determined, and the microscopic morphology of the fracture of the patched veneer was observed by scanning electron microscopy. Numerical simulations were applied to the five designed patch veneer simulation models based on Hankinson’s failure theory, and the stress values and fracture failure patterns were calculated for the five different shapes of patch veneer simulation models. The results were compared with the simulation test results to test the validity of the simulation and to analyze the effect of patch shape on the mechanical properties of the repaired wood veneer and the fracture pattern of the veneer in wood veneer defect gouging and patching technology. The results show that: first, among the five types of patches, except for the diamond-shaped patches, the failure cells of all the veneers extend along 45° direction, and the fracture locations of the specimens under electron microscopic observation show multiple cell wall fractures, and these cells are connected with the fractured cell walls of the board walls to form macroscopic cracks. Second, in the numerical simulation and real measurement, the load carrying capacity and the highest fit with the shape of the nodes. Third, the difference between simulation and actual measurement is within 12.1%, which verifies the feasibility of simulation.更多还原