航天电连接器及其组件失效分析

介绍了航天电连接器及其组件失效分析中初步分析、详细分析、故障假设和最终鉴定四个阶段的内容及方法。阐述了断路、接触不良、瞬断、绝缘不良、短路、误配线、固定不良和密封不良等常见失效模式和失效机理。给出了失效分析的程序和若干检验方法。     

飞控系统故障检测的参数模糊自适应调节

提出通过模型参数的模糊比例积分自适应调节，以校正基于模型的飞控系统故障检测中的系统数学模型偏差。针对模型中误差差较大的迎角导数值，将俯仰角加速度的测量值与教学模型估计值之差作为比例积分调节的反馈量，动态实时校正数学模型参数。     

基于故障树的直升机维修差错分析方法的研究

根据维修差错一人的失误机理、差错的墨菲定律，以及事故链模型和JamesReason模型，提出了基于故障树的主动预先的维修差错分析方法，试图在直升机设计之中和直升机交付使用前，通过这种基于故障树的维修差错分析方法，找出设计中、使用维修及使用管理中出现的问题或维修差错，提出改进措施，防止在使用维修中出现维修差错。通过这种主动事前的预防维修差错分析方法，可以消除或减少维修差错，提高直升机的安全性。     

Aircraft air conditioning system health state estimation and prediction for predictive maintenance

The vast potential of system health monitoring and condition based maintenance on modern commercial aircraft is being realized through the innovative use of Airplane Condition Monitoring System (ACMS) data. However there are few methods addressing the issues of failure prognostics and predictive maintenance for commercial aircraft Air Conditioning System (ACS). This study developed a Bayesian failure prognostics approach using ACMS data for predictive maintenance of ACS. First, a health index characterizing the ACS health state is inferred from a multiple sensor signals using a data driven method. Then a dynamic linear model is proposed to describe the degradation process for failure prognostics. Bayesian inference formulas are carried out for degradation estimation and prediction. The developed approach is applied on a passenger aircraft fleet with ACMS data recorded for one year. The analysis of the case study shows that the developed method can produce satisfactory prognostics results, where all the ACS failure precursors are identified in advance, and the relative errors for the failure time prediction made when just entering the degradation warning stage are less than 8%. This would allow operators to proactively plan future maintenance.     

Applying fuzzy bi-dimensional scenario-based model to the assessment of Mars mission architecture scenarios

Sending man to Mars has been a long-held dream of humankind. NASA plans human planetary explorations using approaches that are technically feasible, have reasonable risks and have relatively low costs. This study presents a novel Multi-Attribute Decision Making (MADM) model for evaluating a range of potential mission scenarios for the human exploration of Mars. The three alternatives identified by the Mission Operations Directorate (MOD) at the Johnson Space Center (JSC) include split mission, combo lander and dual scenarios. The proposed framework subsumes the following key methods: first, the conjunction method is used to minimize the number of alternative mission scenarios; second, the Fuzzy Risk Failure Mode and Effects Analysis (RFMEA) is used to analyze the potential failure of the alternative scenarios; third, the fuzzy group Real Option Analysis (ROA) is used to estimate the expected costs and benefits of the alternative scenarios; and fourth, the fuzzy group permutation approach is used to select the optimal mission scenario. We present the results of a case study at NASA’s Johnson Space center to demonstrate: (1) the complexity of mission scenario selection involving subjective and objective judgments provided by multiple space exploration experts; and (2) a systematic and structured method for aggregating quantitative and qualitative data concerning a large number of competing and conflicting mission events.     

钛合金耳片的静载失效分析与结构优化研究

钛合金因比强度高、耐蚀性好、耐热性高等特点被广泛应用于航空、航天、舰船等领域。飞机在襟翼滑轮架侧板、铰链接头、基座等结构部位采用钛合金零件,其中部分零件涉及耳片连接结构。为了对钛合金耳片进行强度分析和结构优化,开展了不同尺寸钛合金耳片的静载试验研究。揭示了钛合金耳片几何尺寸与加载角度对破坏载荷的影响规律;计算获得轴向加载效率系数K_0与角度加载效率系数K_(con1);对典型断口进行了形貌观察,探讨了钛合金耳片在室温静载荷作用下的破坏机制。     

航空发动机串油故障分析研究

阐述了航空发动机串油故障的特征，从理论上分析了该类故障的机理和对机械系统的危害，指出可以通过黏度、闪点等切实可行的实验方法进行准确分析和诊断，并指明了对此类故障的预防和应对措施。     

液体火箭发动机健康监控──故障分析与仿真

以故障分析为目的，建立了一种大型泵压式液体火箭发动机的基本数学模型及实时数学模型，采用历史数据统计及数字仿真分析结合的方法，对发动机的故障模式及其效应进行了分析研究。提出了液体火箭发动机故障诊断系统的框架。为了对液体火箭发动机健康监控的算法及软件进行验证，以实时数学模型为基础，提供并建立了一个实时仿真验证系统。     

空间环境对航天器影响的统计分析

概括介绍了空间环境的九个主要区域,归纳了它们对航天器各系统的影响。对114例各类环境造成的航天器失效和异常进行了统计分析,在此基础上对引起航天器失效、异常较多的四类空间环境进行了具体分析。     

压缩载荷下夹层结构斜坡过渡区域性能分析

建立了泡沫夹层结构斜坡过渡区域的三维(3D)有限元模型,进行了斜坡过渡区域的坡度角分析优化。基于有限元分析软件MSC.Patran/Nastran,建立了考虑斜坡过渡区面板铺层递减的泡沫夹层结构的有限元模型,研究了结构在单轴压缩载荷作用下的力学行为,进一步讨论了坡度角对于夹层结构过渡区域结构强度和稳定性的影响规律。研究结果表明,泡沫夹层结构坡度角在25°~30°时能够达到提高结构承载能力及减轻结构质量的双重目的。