“航空发动机控制设计中的数值计算原理与实践”课程教学探索

“航空发动机控制设计中的数值计算原理与实践”是飞行器动力工程专业一门重要的专业课程,具有理论性强、数值计算软件掌握要求高、涉及先修课程知识广且联系紧密等特点。针对课程特点,在分析课程知识内在逻辑结构、教学特点和教学现状的基础上,引入发散性思维构建课程知识体系,采用“整体—部分—整体”的教学思路,设计融合先修知识的实践实例,探索课程教学新方法,帮助学生建立航空发动机控制设计中的数值计算的知识构架、理论知识和实践对象间的联系,提高课堂教学和上机实践的成效。     

High cycle fatigue life prediction and reliability analysis of aeroengine blades

Based on the nonlinear continuum damage model(CDM) developed by Chaboche,a modified model for high cycle fatigue of TC4 alloy was proposed.Unsymmetrical cycle fatigue tests were conducted on rod specimens at room temperature.Then the material parameters needed in the CDM were obtained by the fatigue tests,and the stress distribution of the specimen was calculated by FE method.Compared with the linear damage model(LDM),the damage results and the life prediction of the CDM show a better agreement with the test and they are more precise than the LDM.By applying the CDM developed in this study to the life prediction of aeroengine blades,it is concluded that the root is the most dangerous region of the whole blade and the shortest life is 58 211 cycles.Finally,the Cox proportional hazard model of survival analysis was applied to the analysis of the fatigue reliability.The Cox model takes the covariates into consideration,which include diameter,weight,mean stress and tensile strength.The result shows that the mean stress is the only factor that accelerates the fracture process.     

基于混合权重模糊积分法的航空发动机R& D核心能力评价研究

航空发动机R& D核心能力是航空发动机研制水平最集中的体现,我国航空发动机研制水平不高,主要体现在其R &D核心能力不强。当前,打一场航空发动机翻身仗已经成为国家意志。本文从研发制造能力、组织管理能力、自主创新能力和资源整合能力四个方面构建航空发动机R& D核心能力的指标体系,基于熵权和层次分析法确定混合权重,既克服主观权重的人为影响因素,又避免客观权重对数据的依赖性,构建模糊积分评价的数学模型,并选取某航空发动机研究所的5个研发团队,对其R D核心能力评价进行实证分析,得出核心能力评价水平,并对结果进行讨论分析,找出核心能力不足的关键因素,为国家、企业提升航空发动机研制水平进行科学决策提供参考依据。     

滤波耦合法在航空发动机振动去噪中的应用

在航空发动机故障诊断研究中,如何从被干扰的信号中有效去除噪声并提取更为准确的故障信息是十分重要的.本文结合实际问题,在小渡分析和中值滤波两种方法的基础上提出了Db小波与自适应中值滤波耦合法,并用该方法分析了某型航空发动机振动信号,其有效地去除了一系列噪声.