基于随机提前期的备件携行量计算方法

舰艇出海执行任务期间,需要携行一定种类和数量的物资自给。文中研究了这种单级供应条件下,如何确定备件最优携行量的问题。建立了以服务水平为目标,以资源为约束的目标规划模型,模型考虑了随机提前期和备件重要度。提出一种基于边际效费比的增量法用于求解这个模型。最后,给出一个算例并得到了一些结论。     

Inventory pooling games for expensive,low‐demand spare parts

We consider several independent decision makers who stock expensive, low‐demand spare parts for their high‐tech machines. They can collaborate by full pooling of their inventories via free transshipments. We examine the stability of such pooling arrangements, and we address the issue of fairly distributing the collective holding and downtime costs over the participants, by applying concepts from cooperative game theory. We consider two settings: one where each party maintains a predetermined stocking level and one where base stock levels are optimized. For the setting with fixed stocking levels, we unravel the possibly conflicting effects of implementing a full pooling arrangement and study these effects separately to establish intuitive conditions for existence of a stable cost allocation. For the setting with optimized stocking levels, we provide a simple proportional rule that accomplishes a population monotonic allocation scheme if downtime costs are symmetric among participants. Although our whole analysis is motivated by spare parts applications, all results are also applicable to other pooled resource systems of which the steady‐state behavior is equivalent to that of an Erlang loss system. © 2012 Wiley Periodicals, Inc. Naval Research Logistics, 2012     

相控阵天线阵面两级备件优化配置模型

针对相控阵天线阵面备件配置存在的冗余性强、批量送修、多级维修等现实问题,综合考虑备件费用、维修能力以及库存策略之间的关系,建立了基于定期补给的两级备件优化配置模型。给出了系统的故障件维修周转过程和维修备件的定期补给过程,在分析备件、库存、维修能力之间关系的基础上,结合成批到达的排队理论,建立了系统的供应可用度模型。以备件配置费用最小为目标、以系统供应可用度为约束条件,建立了系统的备件优化配置模型,并通过边际效益分析法对模型进行了求解。通过算例仿真与分析对模型进行了验证。结果表明:构建的备件配置能够较好地解决相控阵天线阵面的备件配置问题,具有一定的优越性。     

On the (S − 1, S) lost sales inventory model with priority demand classes

In this paper an inventory model with several demand classes, prioritised according to importance, is analysed. We consider a lot‐for‐lot or (S ? 1, S) inventory model with lost sales. For each demand class there is a critical stock level at and below which demand from that class is not satisfied from stock on hand. In this way stock is retained to meet demand from higher priority demand classes. A set of such critical levels determines the stocking policy. For Poisson demand and a generally distributed lead time, we derive expressions for the service levels for each demand class and the average total cost per unit time. Efficient solution methods for obtaining optimal policies, with and without service level constraints, are presented. Numerical experiments in which the solution methods are tested demonstrate that significant cost reductions can be achieved by distinguishing between demand classes. © 2002 Wiley Periodicals, Inc. Naval Research Logistics 49: 593–610, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/nav.10032     

A two‐echelon inventory‐location problem with service considerations

We study the problem of designing a two‐echelon spare parts inventory system consisting of a central plant and a number of service centers each serving a set of customers with stochastic demand. Processing and storage capacities at both levels of facilities are limited. The manufacturing process is modeled as a queuing system at the plant. The goal is to optimize the base‐stock levels at both echelons, the location of service centers, and the allocation of customers to centers simultaneously, subject to service constraints. A mixed integer nonlinear programming model (MINLP) is formulated to minimize the total expected cost of the system. The problem is NP‐hard and a Lagrangian heuristic is proposed. We present computational results and discuss the trade‐off between cost and service. © 2009 Wiley Periodicals, Inc. Naval Research Logistics 2009     

自行火炮扭力轴载荷谱的测量及疲劳寿命预测

为预测自行火炮扭力轴寿命,对某型自行火炮在不同工况下进行实车试验,获得了多工况下扭力轴的载荷谱。受力分析表明,表面最大拉应力是扭力轴的破坏应力;提出基于随机响应面对扭力轴寿命进行预测的方法,将低周疲劳寿命表达式中的随机参数表示为标准随机变量,引人随机响应的Hermite多项展开式进行拟合,建立了扭力轴疲劳寿命的显式函数。通过对实测载荷谱进行统计分析,依据寿命表达式可以预测扭力轴疲劳寿命,并给出概率分布。该方法弥补了传统响应面法以一般多项式拟合时不能保证收敛性的缺陷。     

工作环境对发动机本体热负荷的影响

为了研究发动机工作环境对发动机本体热负荷的影响,以某型发动机为对象,采用缸内燃烧与冷却系统传热耦合计算方法,建立了温度和大气压力对发动机本体部件热负荷数值仿真模型。通过发动机热平衡台架试验验证了模型最大误差为9.1%,实车试验验证模型最大误差为6.2%。计算表明:发动机出口冷却水温度随环境温度和海拔升高而升高;环境温度46℃时的缸内活塞最高温度比-43℃时升高了15.4%,汽缸套最高温度升高15.5%;海拔高度每升高1 km,活塞最高温度升高1.04%,汽缸套温度升高0.95%。     

通用装备机械部件试验系统设计

针对现有修后试验设备的不足,以柔性装卡、自动控制为设计思想,介绍了通用装备机械部件试验系统的设计过程。该试验系统采用1套柔性支架可完成多种车型、多种机械部件的试验,实现了机械部件操纵的集中控制,提高了试验系统的安全性。     

基于METRIC理论的防空武器系统备件配置优化

利用C+ +Builder 6.0编程软件,编制了专门的计算备件期望短缺量的软件和查询表格,使得METRIC模型的实际运用更加方便;结合我军防空武器系统维修保障体制的现状,利用METRIC模型构建了备件配置优化模型;以备件订购费用为约束条件,装备可用度最大为目标对备件配置策略进行了优化研究;算例分析表明,结果比较合理,...     

基于GERT的武器装备维修备件订货间隔期预测

由于武器装备维修备件的需求是随机波动的,订货间隔期的准确预测就成为了一个难点。针对这样一个随机波动的需求系统,提出了利用GERT随机网络模型对其进行描述,进而求出随机波动需求的订货间隔期的解析表达式,解决了不确定性需求的订货间隔期的预测问题,为武器装备维修备件的科学管理提供数据支持。通过实例验证表明,GERT随机网络模型是解决武器装备维修备件订货间隔期的一种有效手段和方法。