落叶松为基材的木榫旋转焊接性能及机理研究

摘要

选取国产落叶松为木榫旋转焊接基材,对其抗拉拔性能及反应机理进行研究.通过对基材上不同预钻孔/木榫直径比抗拉拔试验,以及木榫直接敲入方式的抗拉拔的对比试验,研究了各因素对焊接性能的影响,并将其结果与欧洲云杉基材进行比较.通过FTIR对落叶松焊接基材情况下木榫及焊接界面进行了化学机理分析.结果表明,木榫旋转焊接落叶松基材的抗拉拔强度与弹性阶段刚度均明显高于欧洲云杉基材;不同预钻孔径对落叶松基材的抗拉拔强度影响不大,但对欧洲云杉影响较大;木榫旋转焊接能够极大提高木榫与基材连接节点的抗拉拔强度,其中落叶松基材提高了416％,而欧洲云杉仅提高了177％.FTIR表明木榫旋转焊接过程中纤维素、半纤维素、木质素发生热解与熔融,冷却后形成高强度的焊接界面.%In order to study the pullout resistance properties and reaction mechanism of wood-dowel rotation welding,this paper discussed the effects of different pre-drilling diameters and difference between hammered method.Larch was selected as the research object and was compared with European spruce welding substrate.The chemical mechanism of the wood-dowel and joint interface was studied by FTIR.The test results indicated that the larch showed higher pullout resistance strength and stiffness than European spruce.The different pre-drilling diameters had little effect on the pullout resistance of larch substrate,but a significant impact on European spruce.Application of wood-dowel rotation welding could greatly improve the pullout resistant strength of the joint.The larch substrate increased by 416％,while European spruce increased by 177％.FTIR analysis indicated that heat degradation of cellulose,hemicellulose and lignin ocurred during the process of wood-dowel welding by high-speed rotation finally it formed a high-strength weld interface.