基于可用度的军用飞机可靠性指标确定方法

军用飞机的可靠性是影响军用飞机可用性和战备完好性的重要因素,在飞机研制阶段建立整机可靠性指标参数的数学模型,确定飞机整机可靠性指标,对于飞机的作战使用具有重要意义.提出一种基于可用度的军用飞机可靠性指标确定方法,来计算经常处于使用状态的军用飞机整机可靠性指标值.     

截击机机载武器装备最优规划的遗传算法研究

机载武器的合理配置是飞机作战效能得以充分发挥的前提条件.本文给出了截击机拦截多目标时的效能评估指标及其与机载武器系统之间的关系模型,并以遗传算法确定了截击机作战效能与武器装备及相关飞行参数的量化关系.经过仿真计算成功地解决了截击机在一定作战条件下,效能指标达到最大时武器装备的最优规划问题.     

基于状态空间的武器装备作战需求模型

以武器装备作战需求为分析对象,构建了数量与战技性能的状态空间和一般作战流程,描述了基于跳跃强度和状态概率的作战需求表达式,解决了作战任务与武器装备之间的映射规则问题。     

基于可靠性的随机拥挤收费模型

提出了一种需求不确定环境下的基于可靠性的拥挤收费模型.在需求不确定的环境下,出行时间的变动使得无论是出行者还是网络决策者都面临着风险.出行者需要提高出行的可靠性以避免迟到,决策者需要在缓解拥堵的同时提高网络整体的可靠性.以基于路段的平均超额出行时间作为出行者的路径选择准则,以平均超额系统总阻抗最小作为决策者拥挤收费的目标,建立了具有均衡约束的数学规划模型.提出了模型能分析出行者的路径选择行为和决策者的决策过程中的可靠性,同时充分考虑迟到等不可靠因素的影响,全面刻画不确定环境下路径出行时间和系统总阻抗的分布特征.数值算例表明,忽略不确定性的影响可能会得到对于网络整体性能过于乐观的评价,得到脱离实际的收费方案.网络的不确定性越高,对于网络性能和收费方案的影响就越大,从而考虑网络可靠性和出行者路径选择的可靠性的必要性就越大.此外,以平均超额系统总阻抗作为拥挤收费的目标可以进一步改善网络的可靠性.     

区间模型的结构可靠性度量方法研究

推导了非概率可靠性指标在应力-强度6种不同取值区间关系图中的含义,给出一个非概率可靠性指标几何意义上的直观理解,提出了根据非概率可靠性指标在图中所对应的夹角大小,进行结构可靠状态的判断方法.针对6种区间关系,利用文章提出的图解法、Ishibuchi、Tanaka提出的区间不等式成立度方法、Sengupta、Pal提出的区间不等式的可接受度方法、非概率可靠性指标定义计算法以及结构安全度方法进行了区间模型的结构可靠性分析.研究发现5种方法对结构的可靠性判定具有一致性,最后通过算例进行了验证.     

装备多寿命指标变量现场数据的可靠性分析

在装备使用保障阶段,对于可由多个寿命指标衡量和控制的装备系统,其可靠性评估及维修保障策略制定都具有重要的工程应用价值.通过对飞机寿命指标不同形式的分析,建立了时间特征与使用特征寿命相关时装备系统多寿命指标变量联合可靠性评估模型,并通过实例对比研究,在评估方法的实用性和有效性等方面均有所改进,为装备多寿命指标变量现场可靠性评估提供了一种方法.     

基于战役的多机种战伤备件需求模型

为了合理储备战时航材备件,通过分析战时故障备件的需求特点,改进了传统的单机故障备件需求模型.根据多机种协同作战任务的不同,引入备件工作运行比的概念,建立了基于作战任务的多机种故障备件需求模型.为解决多机种协同作战时的保障资源配置问题提供了思路和方法.     

基于层次分析法-直觉模糊贝叶斯网络的作战保障能力评估

对作战保障综合能力提出一种新的评估方法,对定性指标构建直觉模糊贝叶斯网络模型,通过贝叶斯推理得到静态作战保障能力;对定量指标用层次分析法确定指标权重,得到动态后勤作战保障能力.采用直觉模糊贝叶斯网络和层次分析相结合的综合评价模型,并引入决策者的偏好因子得到作战保障能力的综合评价值.通过实例分析,验证了该方法的合理性以及有效性.     

修理设备可更换且有修理延迟的N部件串联系统分析

假定部件的寿命服从指数分布,修理延迟时间和修理时间均服从任意分布,并且修理设备的寿命服从指数分布,其更换时间服从任意分布的情况下,利用马尔可夫更新过程理论和拉普拉斯变换工具,研究了修理有延迟且修理设备可更换的n部件串联可修系统,求得了系统的可用度和(0,t]时间内的平均故障次数.进一步,在定义修理设备“广义忙期”下,利用全概率分解,提出了一种新的分析技术,讨论了修理设备的可靠性指标,得到修理设备的一些重要可靠性结果.     

基于Ⅰ-Monte Carlo的飞机研制费用风险建模与实证分析

随着信息化技术在武器装备系统中所占比重的扩大,武器装备系统复杂性急剧增加,装备研制与使用保障费用逐年升高,费用分配不合理和使用率低下等问题越来越严重.飞机作为特殊的复杂装备,费用问题更为严峻.因此,对飞机研制费用风险进行研究,进而为有效提高飞机作战性能、严格控制费用增长提供理论支撑具有重大意义.基于蒙特卡洛在费用风险分析方面的适用性及传统蒙特卡洛的不足,提出了利用基于风险驱动理论的改进蒙特卡洛处理飞机研制费用的风险建模.并以飞机结构件某单位机翼研制项目为例,利用@risk软件进行了费用风险的改进蒙特卡罗建模与分析,对改进方法的合理性和有效性进行了验证.     

航空装备飞行机务准备时间估算方法研究

航空装备飞行机务准备是保持和及时恢复飞机良好状态并使之符合具体飞行任务的重要工作内容,直接影响着飞机的出动强度.以航空装备直接飞行机务准备工作为例,建立航空装备机务准备时间估算模型,对模型进行了求解,实例证明该方法对于估算飞行机务准备维修时间,优化机务准备流程,缩短飞行机务准备时间,完善机务维修保障工作提供了一种有效的途径.     

Optimum design of wing structures with multiple frequency constraints

In this paper, design optimization of aircraft wing structures with multiple frequency constraints was considered. An optimality criterion algorithm along with a scaling procedure was used. Large-scale structural design problems were considered for demonstrating the reliability and efficiency of the algorithm. A simplified fighter wing, and an intermediate-complex wing were considered as design examples. Design histories and the first few frequencies at the initial and final conditions are presented.     

Model-based assessment of military aircraft engine maintenance systems

The paper describes the development and use of a modular system dynamics model for analysing the dynamics and for assessing the long-term performance of military aircraft engine maintenance systems. Life-cycle engine maintenance is considered as a dynamic system whose behaviour is influenced by parameters specific to the engine's reliability and maintenance characteristics, to the operational requirements, and to the maintenance infrastructure. We show how the model can be used for supporting the aircraft procurement decision through the assessment of its engine's maintenance system, as well as for understanding and determining maintenance system behaviours, towards which operational adjustments of the maintenance infrastructure can be made in a more informed way.     

A branch-and-price approach for operational aircraft maintenance routing

In recent years, considerable effort in the field of operations research has been paid to optimizing airline operations, including the logistics of an airline’s fleet of aircraft. We focus on the problem of aircraft routing, which involves generating and selecting a particular route for each aircraft of a sub-fleet that is already assigned to a set of feasible sequences of flight legs. Similar studies typically focus on long-term route planning. However, stochastic events such as severe weather changes, equipment failures, variable maintenance times, or even new regulations mandated by the Federal Aviation Administration (FAA) play havoc on these long-term plans. In addition, these long-term plans ignore detailed maintenance requirements by considering only one or two of the primary maintenance checks that must be performed on a regular, long-term basis. As a result, these plans are often ignored by personnel in airline operations who are forced on a daily basis to develop quick, ad hoc methods to address these maintenance requirements and other irregular events. To address this problem, we develop an operational aircraft maintenance routing problem formulation that includes maintenance resource availability constraints. We propose a branch-and-price algorithm for solving this problem, which, due to the resource constraints, entails a modification of the branch-on, follow-on branching rule typically used for solving similar problems. Through computational testing, we explore the efficiency of this solution approach under a combination of heuristic choices for column (route) generation and selection.     

Numerical investigation of the deformation characteristics and heat generation in pneumatic aircraft tires : Part I. Mechanical modeling

A numerical methodology to study the temperature rise in aircraft tires under free rolling conditions is presented in this article. In the first part, we study the deformation characteristics of the tire to determine the heat generation due to the inelastic deformation (viscoelasticity), which is assumed to be the main source of heat generation under free rolling conditions. The heat generation is then used as an input to solve the heat transfer problem which is addressed in the second part of this article. A methodology which considers a 2-D formulation with the contribution of out-of-plane forces is presented. This methodology allows for a significant reduction of the computational requirements of 3-D analysis while capturing the main 3-D effects. The deformation pattern as well as the stress and strain fields are presented for a cross-section of the tire at several locations.     

Cost evaluation of airline maintenance investigation-triggering methods

A reliable investigation-triggering mechanism is critical for airlines in managing aircraft fleet reliability. This study developed a simulation model to evaluate the performance of various investigation-triggering mechanisms in various scenarios of aircraft fleet reliability. Factors that affect performance include flight delay costs, investigation costs, the costs of corrective actions, the accuracy of investigations, the effectiveness of corrective actions, and the monthly improvement rate. Nine investigation-triggering mechanisms were evaluated. The simulation results show that the monthly improvement rate significantly influences performance. The subject airline’s original investigation-triggering mechanism is not outstanding in most scenarios. This study recommends two of the nine investigation-triggering mechanisms for airlines when they select investigation-triggering mechanisms in various scenarios. Thus, useful guidance for adjusting airlines’ investigation-triggering mechanisms can be effectively provided.     

基于Markov的模块化电传操纵系统软件可靠性模型

电传操纵系统是影响飞行安全的关键系统,建立有效的电传操纵系统软件可靠性模型是软件可靠性测试和验证的基础.针对某型飞机系统安全性设计中横向通道电传操纵系统软件可靠性建模问题,建立了模块化的基于Markov的电传操纵系统软件可靠性模型.提出了综合考虑重要度和复杂度的软件可靠性指标分配方法,将可靠性目标分配到子模块.最后,通过实例验证了所建立的模型和指标分配方法的有效性.     

Scatter Search and Bionomic Algorithms for the aircraft landing problem

The problem of deciding how to land aircraft approaching an airport involves assigning each aircraft to an appropriate runway, computing a landing sequence for each runway and scheduling the landing time for each aircraft. Runway allocation, sequencing and scheduling for each aircraft must ensure the scheduled landing time lies within a predefined time window and meet separation time requirements with other aircraft. The objective is to achieve effective runway use.In this paper, the multiple runway case of the static Aircraft Landing Problem is considered. Two heuristic techniques are presented: Scatter Search and the Bionomic Algorithm, population heuristic approaches that have not been applied to this problem before.Computational results are presented for publicly available test problems involving up to 500 aircraft and five runways showing that feasible solutions of good quality can be produced relatively quickly.     

A systematic design methodology for generating the optimal repairs of aging aircraft

A design methodology which generates optimal mechanical repairs for aging aircraft is presented. Finite element modeling and analysis is used to evaluate the repairs. The repair problem is formulated as an optimization problem using an energy criterion. Optimal locations for rivet placement are found for many different situations.