Studies of bolted joints of dissimilar materials in fatigue: a numerical and finite element approach to connection modelling

建立了许多有限元和数学模型来估计在准静态载荷下机械和粘接接头的应力分布和破坏过程。特别是，研究的重点是建立准静态载荷下螺栓连接的精确模型，但对这些连接的疲劳建模重视不够。本课题旨在研究不同复合材料接头（如碳纤维/环氧树脂到钢）在疲劳下的应力分布和破坏。有限元分析和数学模型将产生各种传统的连接技术。为了验证和改进这些，在进行实验测试之前，将制造一些关节并进行疲劳测试。还将考虑以下疲劳现象：热退化、腐蚀（主要是盐水）、装配/制造变异性的影响（例如，螺栓预应力的变化）。然后，测试结果将为修改初始FEA/matlab应力模型提供进一步的基础，使其与实验结果相似。总体而言，该项目旨在确定不同疲劳机制对接头强度的影响，并随后对这些变化进行计算建模。该提案旨在为航空航天、风能和波浪能应用中常见的疲劳机制建模提供新的见解。

A number of finite element and mathematical models have been produced to estimate the stress distribution and failure processes of mechanical and adhesive joints under quasi-static loading. In particular, studies have focused on producing accurate models of bolted joints in quasi-static loading, but insufficient emphasis has been placed on modelling fatigue of these joints. This research topic looks to investigate the stress distribution and failure of dissimilar composite joints in fatigue (e.g. carbon fibre/epoxy to steel).Finite element analysis and mathematical models will be produced for a variety of conventional joining techniques. For validation and refinement of these, a number of joints will then be manufactured and fatigue-tested before being experimentally tested. The following fatigue phenomena will also be considered: thermal degradation, corrosion (primarily by salt water), effect of assembly/manufacturing variability (e.g., varying bolt pre-stress). Test results will then provide a further basis for altering initial FEA/matlab stress models such that they are analogous with experimental results. Overall, the project aims to identify the effects of different fatigue mechanisms on joint strength and subsequently model these variations computationally. The proposal looks to provide novel insight into the modelling of fatigue mechanisms commonly encountered in aerospace, wind and wave power applications.