Mechanism of Strength of Nailed Joints Using Auto-nailers

自动钉机的发展带来了驱动钉安装方面的重大进步。这种动力设备的使用大大提高了速度。对自动钉钉机的基础研究主要集中在机器的工作机理上，对钉钉接头力学性能的研究很少。本研究的主要目的是研究自动钉钉机和锤头驱动钉钉接头的回撤强度和侧向强度。抗拔强度：主要目的是验证木材钉断与抗拔强度之间的关系。扫描电镜研究表明，车速越高，木材劈裂越大。已有的理论认为，大劈裂降低了抽拔强度，但相反，抽拔强度与钉劈木材的面积成正比。环柄钉对木材的破坏作用明显，因此动力驱动与锤击驱动的回撤强度差异较小。侧位强度：x线照射下观察侧位强度。结果总结如下：1)气枪驱动钉钉节点的侧移强度与锤击驱动钉钉节点的侧移强度基本相同。但动力驱动钉用塑料片连接的问题有待进一步研究。2)由于环形钉对木材的破坏较大，因此横向强度小于光滑钉和螺旋钉。本研究验证了动力驱动钉接头的力学性能。我想在这一领域进行进一步的研究，开发新型钉子。

Major advances in the installation of driven nails has been brought about by the development of auto-nailers. The use of such power equipment greatly increases the speed. The basic research on auto-nailer has focused on the mechanism of the machine and the research on the mechanical properties of the nailed joints was very few. The main objective of this research is to investigate the withdrawal strength and lateral strength of nailed joints driven by auto-nailers and hammer.1.withdrawal strength : The prime object is to verify the relationships between split of wood by nailing and withdrawal strength. According to the research by scanning electron micro-scope , higher speed driving caused larger split of wood . An established theory says that large split decreased the withdrawal strength but on the contrary withdrawal strength was proportional to the area of split of wood by nailing . Ring shank nails damaged the wood significantly so the difference of withdrawal strength between power driven and hammer driven was small.2. Lateral strength : Lateral strength was investigated with X-ray irradiation. The results were summarized as follows. 1) Lateral strength of nailed joints driven by pneumatic guns was almost the same as that of hammer driven nailed joints . But the nails for power driven were connected using plastic sheets should be studied in the future. 2) Since ring nails damaged the wood significantly, the lateral strength was smaller than that of smooth shanked nails and screw-shanked nails This study verified the mechanical properties of power driven nailed joints . I would like to proceed further studies in this field and develop new type nails.