A proposal of high strength wooden nail for environmentally friendly building

环保建筑用高强度木钉的方案

• 批准号: 16510060
• 负责人: INOUE Masafumi
• 金额: $ 2.43万
• 依托单位: The University of Tokyo (2005)Kyoto University (2004)
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2004
• 资助国家: 日本
• 起止时间: 2004 至 2005
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16510060/
• 关键词: bamboo; densification; connector; nail; architecture; furniture; high-strength; recycle

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.

本研究探讨压缩木钉或压缩竹钉作为房屋建筑扣件的可能性及其与自动打钉机的适应性。木钉有以下几点优点：1.当回收或报废时，不必与木质部分相匹配。可与木框或板材一起用木工机械切割，重复使用.它既不会引起金属污染，也不会引起水分冷凝的损害.它足够轻，在承受负荷和抗震设计方面具有优势。将竹秆分成12至16段，交替定向，内外方向，用粘合树脂压缩它们，将条带的曲率弯曲成扁平形式。竹条在压缩过程中相互约束，实现了较大的变形而不断裂。用竹（Madake）压缩53%，在密度为1.45g/cm ^3的条件下，可以得到抗弯强度大于400 MPa的高强度材料，钉头是钉接时增加抗拔力的重要因素。因此，我们尝试将髓内钉成形为偏置头。此外，刺入竹基后，钉尖处的压缩力恢复，使竹基的长度增加，达到与咬紧竹基相同的效果。作为竹基长维管束鞘分离的预处理，我们尝试了碱处理、蒸煮、汽爆及其组合。作为结果的一个实例，产物的密度为约1.33-1.43g/cm^3。与普通钢钉相比，竹钉的弹性模量（莫伊）和抗弯强度（莫尔）分别超过40 GPa和400 MPa，竹钉具有较高的刚度、屈服强度和最大强度，但韧性较低。