A proposal of high strength wooden nail for environmentally friendly building

在本研究中，我们探讨了压缩木钉或竹钉作为房屋建筑紧固件的可能性及其对自动钉机的适应性。木钉有以下优点：回收或刮削时，不需要与木制部件分拣。重复使用时，可与木材火焰或木板一起由木材机械切割。它既不会造成金属的污渍，也不会造成湿气凝结的破坏。它足够轻，在承受载荷和抗震设计方面具有优势。将竹竿分成12到16片，交替向外和向内方向排列，用粘胶树脂将其压缩，弯曲成平坦的形状。竹条在压缩过程中相互约束，实现了更大的变形而不断裂。可以得到一个宽的竹平板。我们可以在密度为1.45g/cm^3的情况下，通过对竹子（made）进行53%的压缩，获得MOR大于400Mpa的高强度材料。钉头是重要的，以增加退出阻力，当面板连接到火焰钉。因此，我们尝试用偏移头来塑造钉子。此外，它增加了通过穿透基材后在钉点的压缩恢复，从而产生与握紧相同的效果。作为分离竹条长维管束鞘的前处理方法，我们尝试了碱处理、蒸煮、蒸汽爆破及其组合处理。作为结果的一个例子，产品的密度在1.33-1.43g/cm^3之间。MOE和MOR分别超过40GPa和400MPa。与普通钢钉相比，竹钉具有较高的刚度、屈服和最大强度，但韧性较低。

In this research, we investigate the possibilities of compressed wood or bamboo nails as fastener in house construction and its adaptability to automatic nailer. Wooden nails have some points of advantage as follows :1. It does not have to assort from wooden part when recycling or scraping.2. It can be cut by wood machinery together with wood flame or panels when reusing.3. It causes neither the stain by metal nor the damages by moisture condensation.4. It is enough light to have an advantage in withstand load and seismic-resistant design.Splitting bamboo culms into 12 to 16 pieces, alternatively orienting, to outer and inner directions, compressing them with adhesive resin, the curvature of the strips is bent into flat form. The bamboo strips restrain each other during compression, which achieved greater deformation without breakage. A wide bamboo flat board can be obtained.We could obtain high strength material more than 400Mpa in MOR at density of 1.45g/cm^3 by 53% compression of bamboo (Madake).Nail head is important to increase withdrawal resistance when the panels joint to the flame by nails. Thus, we try to shape the nail with offset head. Furthermore, it increases by recovery of compression at nail point after piercing through the base material resulting in the same effect as clenching.As a pre-treatment to separate the long vascular bundles sheath from bamboo strips, we have tried the alkali treatment, steaming, steam explosion, and their combinations. As an example of the results, density of the products was around 1.33-1.43g/cm^3. The MOE and MOR exceeded 40GPa and 400MPa, respectively.The higher stiffness, yield and max strength, but lower toughness can be observed in bamboo nail compared to steel common nail.