Novel liquid composite connections for glass structures

透明、高质量的抛光、耐用和相对较低的成本相结合，使玻璃成为建筑中独特的材料。虽然玻璃本身是一种古老的材料，但它的性质仍然相对未知。正是由于它最近的流行，关于开发其结构性能的研究才有所增加。目前玻璃结构应用中最关键的问题之一是如何将这种材料连接到底座以及相邻的面板/其他玻璃部件上。直到最近，在高应力应用中连接的唯一选择是在完全钢化的玻璃中使用螺栓组件。因此，本项目致力于确定玻璃在其替代条件下(即，退火和钢化)使用的潜在机械适宜性，因为这些条件在建筑业中已被广泛使用。然而，使用螺栓连接来连接脆性材料是非常低效的，因为母材中的拉应力集中很大。因此，重点将放在为结构玻璃应用开发新颖且可行的替代粘接解决方案上。一个明显的解决方案是粘接，因为这样可以均匀地分配载荷，降低应力集中，并且只需要很少的表面处理。胶粘剂的主要缺点是其长期性能(即在长期载荷和环境老化下)不容易量化，并且差热膨胀对胶接接头的影响仍未得到解决。这些不确定性导致了令人望而却步的巨大安全系数，大大限制了它们的使用。一般情况下，使用胶粘剂和结构夹层作为螺栓连接的替代品已被研究过。本项目旨在通过研究其在加载时间和温度下的结构行为来解决与其耐久性和稳定性相关的不确定性。更详细地说，可以进行长期循环作用(如自重、温度循环、冻融循环、太阳辐射和波动风压)和加速老化试验，以验证粘合剂在疲劳、蠕变和脆化方面的性能。然而，由于粘接技术的实质性改进，最近的实验研究表明，玻璃失效最终可能成为连接设计的限制因素。因此，本项目旨在阐明拟议的创新接头的失效机制，特别是接头玻璃阶段的剪切失效(即玻璃拔出)。此外，还将尝试确定扩大研究范围以包括其他材料的潜在适用性，这些材料可以取代用于螺栓/胶粘连接的传统材料，这些材料是从制造商的数据表上列出的性能列表中选择的，并咨询了行业专家。为此，该项目的重点是检查这些材料，以建立关于其机械和热行为的确凿的材料定律。除此之外，另一种可能的途径是研究将用于粘结其他结构材料(例如工程陶瓷)的工艺(例如扩散粘接)的可能性以及这些技术在玻璃连接中的潜在适用性。

The combination of transparency, high quality finish, durability and relatively low cost make glass a unique material in buildings. While glass itself is an ancient material, its properties are still comparatively unknown. It is only due to its recent popularity that research on developing its structural performance has increased. One of the current most critical issues in the structural use of glass is how is the best way to connect this material to the substructure as well as to adjacent panels/other glass pieces.Until recently the only option for connections in high stress applications was the use of bolted assemblies in fully toughened glass. Therefore, this project endeavors to identify the potential mechanical suitability for the use of glass in its alternative conditions (i.e. annealed and toughened) as these are already widely used in the construction industry. However, the use of bolted connections for joining brittle materials is highly inefficient due to large tensile stress concentrations in the parent material. Consequently, focus will be given on developing novel and simultaneously viable alternative bonding solutions for structural glass applications. One obvious solution is adhesive bonding as this evenly distributes the load, reduces stress concentrations and requires very little surface preparation. The main drawback of adhesives is that their long-term performance (i.e. under long-term loading as well as environmental ageing) is not easily quantified and the effect of differential thermal expansion on adhesive joints remains unresolved. These uncertainties lead to prohibitively large safety factors limiting their use dramatically. Generally, the use of adhesives and structural interlayers as alternatives to bolted connections has been investigated. This project seeks to address the uncertainties associated with their durability and stability by investigating their structural behavior over load time and temperature. In more detail, cyclic long term actions (such as self-weight, temperature cycles, freeze-thaw cycles, solar radiation and fluctuating wind pressures) and accelerated ageing tests can be carried out to validate the performance of the adhesives regarding fatigue, creep and embrittlement. However, due to substantial improvements in adhesive technology, recent experimental research has shown that glass failure might eventually be the limiting factor in design of connections. Hence, this project aims to illustrate the failure mechanisms of the proposed innovative joints and especially the shear failure in the glass phase of the joint (i.e. glass plucking).Additionally, attempts will be made to establish the potential suitability of extending the research to include other materials that can replace the conventional used in bolted/adhesive connections, chosen from the properties listed on manufacturers' datasheets and consultation with industrial experts. To this purpose, the project focuses on the examination of these materials to establish a substantiated material law for their mechanical and thermal behavior. Apart from this, another potential route is to examine the possibility of incorporating processes (e.g. diffusion bonding) used to bond other structural materials (e.g. engineered ceramics) and the potential applicability of these techniques in glass connections.