Adaptive cycle counting for accurate fatigue damage prediction considering large and small cycles

考虑大循环和小循环的自适应循环计数可实现准确的疲劳损伤预测

• 批准号: 485099-2015
• 负责人: Kim, IlYong
• 金额: $ 1.82万
• 依托单位: Queen's University
• 依托单位国家: 加拿大
• 项目类别: Engage Grants Program
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=584725
• 关键词: Adaptive; cycle; counting; accurate; fatigue

Given the severe safety and financial consequences associated with any turbine failure, the ability to successfully predict the lifetime of a gas turbine is of critical importance to gas turbine owners and operators in the aerospace industry. Moreover, correctly identifying the lifetime of a turbine significantly reduces the cost of gas turbine fleet ownership, as owners are able to reduce maintenance costs by employing optimized overhaul and maintenance intervals as opposed to uncertain, and thus conservative estimates. The objective of the proposed research is to increase the accuracy and reliability of gas turbine prognostic systems, to further reduce the cost of turbine ownership. The current method for estimating damage accumulated during a fatigue cycle requires the strain range at fracture critical locations (FCL), which is calculated with FEA (finite element analysis) at the maximum and minimum conditions of the cycle. A Manson-Coffin type relationship is then used to relate strain range to fatigue damage. However, there is not necessarily a linear relationship between the measured operating parameter and the strain at the FCL; factors such as geometric stress concentration factor and material plastic behaviour may influence the strain range. Therefore, applying a constant pre-defined threshold could result in either missing significant cycles or counting unnecessary cycles. Improvements to the current method could take the form of an adaptive threshold, or other numerical techniques. This project will utilize non-linear FEA to analyze the accuracy of, and to make improvements to, the cycle counting method.

考虑到与任何涡轮机故障相关的严重安全和财务后果，成功预测燃气轮机使用寿命的能力对于航空航天业的燃气轮机所有者和运营商至关重要。此外，正确确定涡轮机的使用寿命可显着降低燃气轮机机队的拥有成本，因为业主能够通过采用优化的大修和维护间隔来降低维护成本，而不是不确定的保守估计。本研究的目的是提高燃气轮机预测系统的准确性和可靠性，进一步降低涡轮机的拥有成本。 目前估计疲劳循环期间累积损伤的方法需要断裂临界位置 (FCL) 的应变范围，这是在循环的最大和最小条件下使用 FEA（有限元分析）计算的。然后使用 Manson-Coffin 型关系将应变范围与疲劳损伤联系起来。然而，测量的工作参数和 FCL 处的应变之间不一定存在线性关系；几何应力集中系数和材料塑性行为等因素可能会影响应变范围。因此，应用恒定的预定义阈值可能会导致丢失重要周期或计算不必要的周期。对当前方法的改进可以采取自适应阈值或其他数值技术的形式。该项目将利用非线性有限元分析 分析周期盘点方法的准确性并对其进行改进。