Hygrothermal effect on the fracture/fatigue behaviour of adhesively bonded repairs

湿热效应对粘合修复的断裂/疲劳行为

• 批准号: 529660074
• 负责人: Professor Dr.-Ing. Joachim Hausmann
• 金额: --
• 依托单位: Leibniz-Institut für Verbundwerkstoffe (IVW)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/529660074?language=en
• 关键词: Hygrothermal; effect; fracture; fatigue; behaviour

Structural applications of composite materials have been increasing in the transportation industry because they present good mechanical properties (high stiffness and strength) associated with low weight. They enable fuel saving and performance improvement. However, composite components are prone to delamination damage, mainly under bending loads. Because of this issue, locally damaged regions can compromise the complete structure, which leads to premature replacement of large structural components with obvious economic and ecological costs due to waste of material. Therefore, a viable alternative is to repair damaged components. Adhesive bonding is becoming one of the most suitable and attractive techniques for joining and repairing composite parts and it has proven to be very effective (uniform stress distribution over the bonded area, less weight penalty and higher fatigue and corrosion resistance). Nevertheless, before its complete implementation, it is necessary to fully understand its behavior under fatigue, which is a predominant type of loading in the transportation industry. In these applications, structures are also frequently under severe environments, making it essential to evaluate the influence of hygrothermal conditions (moisture and temperature) on their mechanical behavior. Thus, it is important to develop numerical predictive tools that take into account the combined effect of the environment and fatigue. However, such numerical works are rather scarce and the majority of tools are semi-empirical; which means that they require extensive experimental testing to fine-tune the models. The current proposal aims to develop a progressive damage model incorporating the effects of fracture, fatigue and environmental degradation. Such model will be based on suitable “ageing factors” derived from appropriate relations as Fickian diffusion models and the experimental Paris curves.

复合材料的结构应用在运输行业中一直在增加，因为它们具有良好的机械性能（高刚度和强度）与低重量相关。它们可以节省燃料和性能。但是，复合组件容易受到分层损坏，主要是在弯曲载荷下。由于这个问题，当地损坏的地区可能会损害完整的结构，从而导致由于浪费物质而过早替换大型结构成分，并以明显的经济和生态成本替换。因此，可行的替代方法是修复损坏的组件。粘合键合成为连接和修复复合零件的最合适，最有吸引力的技术之一，事实证明，它非常有效（粘结面积上的应力分布均匀，重量损失较小，较高的疲劳和耐腐蚀性）。然而，在完整实施之前，有必要在疲劳下充分了解其行为，这是运输行业中主要的负载类型。在这些应用中，结构也经常在严重的环境下，因此必须评估湿热条件（水分和温度）对其机械行为的影响至关重要。这是重要的是开发数值预测工具来考虑环境和疲劳的综合效果。但是，这种数字作品相当稀缺，大多数工具都是半经验的。这意味着他们需要大量的实验测试来微调模型。当前的提案旨在开发一个编码断裂，疲劳和环境降解影响的渐进损害模型。此类模型将基于适当关系的适当“老化因素”，例如Fickian扩散模型和实验性巴黎曲线。