【作者】 林杰威；

【导师】 张俊红；

【作者基本信息】 天津大学 ， 动力机械及工程， 2009， 硕士

【摘要】 叶片是航空发动机的主要组成部分,是发动机的关键转动部件之一,担负着能量转化的重任。常见的导致叶片失效的因素有低循环疲劳、振动、屈曲、蠕变等。随着现代航空发动机推重比的不断提高,叶片的设计应力水平大幅提高,低循环疲劳失效逐渐成为叶片最主要的失效形式之一,多发生在叶片根部两侧气流进出口处等应力集中较严重的部位。本文通过理论分析与试验研究相结合的研究方法,就叶片疲劳可靠性的分析方法与可靠性模型的建立进行了研究,主要内容如下:1.对目前工程中广泛应用的疲劳寿命估算方法和可靠性分析方法进行了系统评述,从中找到了适用于本研究中航空发动机压气机叶片疲劳寿命和可靠性研究的方法。2.根据国家标准对叶片材料钛合金TC4的疲劳试验进行了设计,通过材料疲劳试验获得了包括S-N曲线、σ?ε曲线在内的材料力学性能指标,为后续的疲劳寿命估算和疲劳可靠性分析打下基础。3.建立了叶片的有限元模型,并进行了特定工况下的模型瞬态分析。通过分析应力响应的结果确定了疲劳危险部位,同时得到了叶片的载荷历程,为疲劳寿命估算做准备。4.结合材料疲劳试验和有限元分析得到的结果,采用名义应力法和Miner线性损伤累积准则,联合疲劳分析软件对叶片进行全寿命分析,得到了叶片的疲劳损伤云图和寿命分布,以此找出了失效将会发生的部位,并与叶片实际失效情况进行比较,结果十分吻合。5.利用应力-强度干涉模型对叶片的可靠性进行分析,给出叶片的可靠度。叶片是航空发动机中的安全关键件,它对整个装置的可靠性有决定性影响,因此研究航空发动机叶片的疲劳寿命和可靠性有着重要的研究意义和工程应用价值。更多还原

【Abstract】 Aviation engine blade is a major component of the engine and one of the key rotating components, which is charged with the important task of energy conversion.Common factors that lead to blade failure include low cycle fatigue, vibration, buckling, creeping and so on. With the improvement of the modern aviation engine Thrust-Weight Ratio, the design leaves a substantial increase in stress levels, while low-cycle fatigue failure roulette gradually become one of the most important failure mode. Low-cycle fatigue failure mostly occurred in the department where stress concentrated such as the two sides of the blade root where airflow passes in and out.With a combination of theoretical analysis and experimental study methods, here in this paper we studied the blade fatigue reliability analysis methods and the reliability as follows:1. A systematic review over the current widely used methods in estimating the fatigue life and reliability analysis, in order to find out applicable research methods for this text.2. In accordance with national standards we designed the blade material TC4 titanium alloy fatigue test and through this test we get a series of Mechanical properties of the materials, including the S-N curve, theσ?εcurve which lay the foundation for the future fatigue life estimate and reliability analysis of fatigue.3. Established the finite element model of the blade, and conduct the transient analysis on specific conditions. By analyzing the results of the stress response we defined the dangerous fatigue parts, and get the blade course load at the same time, which make preparations for the estimating of fatigue life.4. Joint with the results of fatigue test and finite element analysis, using Nominal Stress Method and Miner’s Linear Damage Accumulation criteria, and utilizing the fatigue analysis software we made the life-wide analysis of the blade and got Fatigue damage nephogram and age distribution. On this account we identified the department where failure may occur and defined it match the actual result after comparison.5. Analysis the reliability in the light of Stress-Intensity Interference Model and define the reliability of the blade.Blade is also a key point for the aero-engine safety. It has a decisive impact on the reliability of the entire device. Therefore the study on aero-engine blade fatigue life and reliability has important study significance and great engineering application values.更多还原