Novel liquid composite connections for glass structures

用于玻璃结构的新型液体复合连接

• 批准号: 2109245
• 金额: --
• 依托单位: University of Cambridge
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2018
• 资助国家: 英国
• 起止时间: 2018 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2109245
• 关键词: Novel; liquid; composite; connections; glass

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.

透明性、高质量饰面、耐用性和相对较低的成本使玻璃成为建筑物中的独特材料。虽然玻璃本身是一种古老的材料，但其性质仍然相对未知。只是由于它最近的流行，研究开发其结构性能有所增加。目前，在玻璃的结构应用中最关键的问题之一是如何将这种材料连接到下部结构以及相邻面板/其他玻璃件的最佳方式。直到最近，在高应力应用中连接的唯一选择是在全钢化玻璃中使用螺栓组件。因此，本项目致力于确定在替代条件下（即退火和钢化）使用玻璃的潜在机械适用性，因为这些玻璃已广泛用于建筑行业。然而，由于母体材料中的大的拉伸应力集中，使用螺栓连接来连接脆性材料是非常低效的。因此，重点将放在开发新的，同时可行的替代粘合解决方案的结构玻璃应用。一个明显的解决方案是粘合剂粘合，因为这可以均匀分布负载，减少应力集中，并且只需很少的表面处理。粘合剂的主要缺点是其长期性能（即在长期负载以及环境老化下）不容易量化，并且差异热膨胀对粘合剂接头的影响仍未得到解决。这些不确定性导致了极大的安全因素，极大地限制了它们的使用。通常，已经研究了使用粘合剂和结构夹层作为螺栓连接的替代品。该项目旨在通过调查其在荷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，可以进行循环长期作用（例如自重、温度循环、冻融循环、太阳辐射和波动风压）和加速老化测试以验证粘合剂关于疲劳、蠕变和脆化的性能。然而，由于粘合剂技术的实质性改进，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，本项目旨在说明所提出的创新节点的破坏机制，特别是节点玻璃相的剪切破坏（即玻璃拔出）。此外，将尝试确定扩展研究的潜在适用性，以包括可替代螺栓/粘合剂连接中使用的传统材料的其他材料，从制造商说明书上列出的性能中选择，并咨询工业专家。为此，该项目的重点是检查这些材料，以建立一个充实的材料法，为他们的机械和热行为。除此之外，另一个潜在的途径是研究结合用于结合其他结构材料（例如工程陶瓷）的工艺（例如扩散结合）的可能性以及这些技术在玻璃连接中的潜在适用性。