推挂机驱动齿轮断裂浅析

对包果推挂机驱动具轮在运行过程中发生的齿根处破坏进行了宏观、微观和显微组织等方面的分析，并在原零件相应部位进行了口模拟验证试验，从而确定了零件断裂的原因。     

双层项目驱动的“二四四”课程考核模式构建——以《ACCESS数据库程序设计》为例

改变传统的课程教学与考核模式,将先进的教考模式与策略思想融入计算机系列课程教学改革过程中,不仅可提高课程教学质量,也利于促进人才培养质量的提升。本文以《ACCESS数据库程序设计》课程为例,详细阐述了"双层项目驱动的‘二四四’课程考核模式"的构建。实践证明,这种模式有助于教学质量的提高,对学生自主性、研究性、协作性学习能力的培养起到了积极作用,值得进一步完善和推广。     

一类非线性系统的故障可诊断性量化评价方法

为将提高卫星控制系统故障诊断能力的工作重点前移到地面设计阶段,针对其中的关键问题--可诊断性评价,提出一种适用于非线性模型的可诊断性量化评价方法,对传统定性评价研究进行了有效的扩展和延伸。鉴于线性化处理导致非线性因素引起的故障被忽略,将卫星控制系统描述成一类仿射非线性模型;并基于微分几何理论,给出可诊断性（包括可检测性和可隔离性）的定义和定性评价指标--不变最小对偶分布。通过子空间相似度判别准则,根据故障方向矢量和所得不变分布以及不同故障方向矢量之间的夹角关系,分别设计可检测性和可隔离性的量化指标,并给出具体评价流程;该指标能够明确故障被检测和隔离的难易程度,并可用于指导诊断算法的设计和传感器的优化配置。最后,以动量轮为仿真实例校验本文所提方法的正确性;仿真结果表明：该方法在不依赖任何诊断算法和具体故障模式的前提下,可以实现可检测性和可隔离性的准确量化评价。     

Whole-process design and experimental validation of landing gear lower drag stay with global/local linked driven optimization strategy

Landing gear lower drag stay is a key component which connects fuselage and landing gear and directly effects the safety and performance of aircraft takeoff and landing. To effectively design the lower drag stay and reduce the weight of landing gear, Global/local Linked Driven Optimization Strategy (GLDOS) was developed to conduct the overall process design of lower drag stay in respect of optimization thought. The whole-process optimization involves two stages of structural conceptual design and detailed design. In the structural conceptual design, the landing gear lower drag stay was globally topologically optimized by adopting multiple starting points algorithm. In the detailed design, the local size and shape of landing gear lower drag stay were globally optimized by the gradient optimization strategy. The GLDOS method adopts different optimization strategies for different optimization stages to acquire the optimum design effect. Through the experimental validation, the weight of the optimized lower dray stay with the developed GLDOS is reduced by 16.79% while keeping enough strength and stiffness, which satisfies the requirements of engineering design under the typical loading conditions. The proposed GLDOS is validated to be accurate and efficient in optimization scheme and design cycles. The efforts of this paper provide a whole-process optimization approach regarding different optimization technologies in different design phases, which is significant in reducing structural weight and enhance design precision for complex structures in aircrafts.     

基于DS证据理论的航天设备寿命预测方法

以动量轮为研究对象,提出一种基于D S证据理论和Bayes理论的信息融合及寿命预测方法。首先,挖掘多个寿命信息源的内、外部信息作为Bayes多源验前信息,并构建证据集合;其次,利用合成规则对证据集合进行合成,得到合理的验前融合权重的分配结果;然后,利用Bayes方法求解寿命参数的融合验后分布,并计算寿命参数的估计值;最后,根据参数估计值预测设备的剩余寿命。仿真结果表明,基于多源寿命信息融合的预测结果与单一来源的寿命预测结果相比,更加接近于设备的真实寿命信息。     

Trajectory Analysis of Fuel Injection into Supersonic Cross Flow Based on Schlieren Method

Trajectory analysis of fuel injection into supersonic cross flow is studied in this paper. A directly-connected wind tunnel is constructed to provide stable supersonic freestream. Based on the test rig, the schlieren system is established to reveal the fuel injection process visually. Subsequently, the method of quantitative schlieren is adopted to obtain data of both fuel/air interface and bow shock with the aid of Photoshop and Origin. Finally, the mechanism based on two influential factors of fuel injection angle and fuel injection driven pressure, is researched by vector analysis. A dimensionless model is deduced and analyzed. The curve fitting result is achieved. The relationship between the data and the two influential factors is established. The results provide not only the quantitative characteristics of the fuel injection in supersonic cross flow but also the valuable reference for the future computational simulation.     

定量与定性相结合的动量轮故障可诊断性评价

为了提高动量轮的故障诊断性能,采用定量与定性相结合的方法对故障可诊断性评价方法开展研究。在分析动量轮和控制器模型的基础上,建立定量的动量轮闭环系统模型;分析动量轮的各种故障模式,将其分为测量类、驱动类和控制器类故障,并在动量轮系统模型中进行表示;依据故障到输出的传递函数是否等于0以及不同故障到输出的传递函数是否相同的思路,研究各类故障的可检测性和可分离性判断条件,对动量轮的各故障模式进行评价,给出相应的评价结果对于不可分离的故障集合,研究基于定性模型的故障可诊断性评价方法,即根据动量轮各功能模块之间的关系,结合动量轮的故障模式影响分析结果,建立故障与征兆之间的关联矩阵,通过分析各故障对应的数据,进一步给出动量轮故障可诊断性的评价结果。最后,提出故障可诊断性相关的定量指标,根据动量轮故障可诊断性评价结果,给出各故障以及动量轮的可检测度和可分离度等,为后续故障可诊断性设计提供依据。     

动量轮失效物理模型试验方案研究

论述了动量轮失效物理模型及其试验方法, 其目的是提高动量轮产品的研制水平和进行动量轮寿命预计. 文章主要内容包括失效物理模型、试验环境模拟、试验模型技术状态的认可、失效影响因素分析、试验过程中数据采集方法及建立失效物理的数学评判表达式.      

廊坊实施创新驱动发展研究

创新驱动是已经成为廊坊的主导发展战略,只有创新驱动才能使廊坊产业结构不断优化、创新能力不断提高、创新环境不断完善,进而提升廊坊的综合竞争力。廊坊的的发展必须坚持走创新驱动的发展模式。     

紧凑布局核心机驱动风扇级设计参数影响分析

以某核心机驱动风扇级(Core driven fan stage,简称CDFS)的气动方案为例,使用新版Denton程序通过数值模拟分析了气动布局、预旋分布和转子径向负荷分布对CDFS性能的影响。数值结果表明:利用CDFS静子取代高压压气机进口导叶是一种紧凑高效的CDFS气动布局;CDFS效率所受的影响主要来自转子效率的变化,工作裕度所受的影响主要来自静子负荷的变化;增加CDFS转子叶根的设计压比可以降低CDFS静子叶根的气动负荷,从而使CDFS获得更为均衡的性能。