Investigation into the fundamentals of contact mechanics in turbine blades roots to enable improved techniques for design optimisation and reliability

研究涡轮叶片根部接触力学的基础知识，以改进设计优化和可靠性技术

• 批准号: 2397291
• 金额: --
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2397291
• 关键词: Investigation; into; fundamentals; contact; mechanics

In a turbofan engine a large number of metal on metal contacts are present at the base of the fan blades. Theses contacts are subject to varying loads, both due to thermal effects and resulting from vibrations present with the engine; under these conditions a damage phenomenon known as fretting fatigue can occur. Understanding processes and conditions that lead to material degradation and crack initiation is crucial to accurately predict the lifetime of engine components, and to ensure safety in engine design. The overall goal of this work is to advance the understanding of contact mechanics in turbine blade roots to enable improved techniques for design optimisation and life prediction via enhanced understanding of the stress-state in the vicinity of the contact.The project will be complementary to the fundamental contact research being undertaken by Rolls-Royce plc as part of their Cornerstone research project and will incorporate work on contacts at a fundamental level but will also consider features specific to turbine components.A part of this project will involve an experimental investigation into the effect of various parameters on the expected lifespan of a contact. Parameters to be considered for testing include; material orientation effects in single crystal materials, contact geometry (flat/barrelled), local geometry effects (e.g. proximity of stress raisers such as notches or corners) & temperature. Many of these contact properties (such as material orientation effects and local geometry effects) have not previously been studied in any depth in the context of fretting fatigue, and as such their effects are currently poorly understood. The test results will be used to advance understanding of the fundamental mechanics and the influence of the parameters investigated.The other part of this project will be analytical in nature; informed by the results of the experiments numerical and analytical models will be developed to model the state of stress and expected lifetime of the contact. Methods employed in modelling the contact pressure, shear traction and their associated stress fields may include; The use of Finite element software, The Distributed dislocation technique, Direct analytical solutions and the use of asymptotic stress fields. These methods will require modification from their standard forms to allow for the effects being investigated.This project falls within the EPSRC engineering Theme and is related to the Materials Engineering - Metals & Alloys research area.

在涡轮喇叭发动机中，在风扇叶片的底部存在大量金属触点上的金属。由于热效应和发动机的振动导致的，这些接触的载荷都会有不同的负载。在这些条件下，可能会发生一种称为“毛线疲劳”的损伤现象。了解导致物质降解和裂纹启动的过程和条件对于准确预测发动机组件的寿命以及确保发动机设计的安全至关重要。这项工作的总体目标是提高对涡轮机叶片根部接触力学的理解，以通过增强对接触接触附近的压力状态的理解来提高设计优化和生活预测的技术。该项目的一部分将涉及对各种参数对接触寿命的影响的实验研究。要考虑进行测试的参数包括；材料定向效应在单晶材料中，接触几何形状（平坦/桶形），局部几何效应（例如，应力促进剂（例如凹口或角落）和温度的邻近性。这些接触属性中的许多（例如材料取向效应和局部几何效应）以前尚未在疲劳的情况下进行任何深度研究，因此目前对其效应的理解很少。测试结果将用于提高对基本力学和所研究参数影响的理解。该项目的另一部分本质上是分析性的。通过实验的结果和分析模型的结果，将开发出来，以模拟接触的压力状态和预期的寿命。在建模接触压力，剪切牵引力及其相关应力场中采用的方法可能包括：使用有限元软件，分布式错位技术，直接分析解决方案以及渐近应力场的使用。这些方法将需要从其标准表格中进行修改，以允许所研究的效果。该项目属于EPSRC工程主题，与材料工程 - 金属和合金研究领域有关。