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     

基于响应面法的复合材料层合板平面应力强度可靠性分析

针对处于平面应力状态下的复合材料层合板，考虑其材料参数、强度参数、几何尺寸以及承受载荷等随机因素，用分支限界法识别结构系统的各重要失效序列，应用响应面法对某具体层合板的各失效事件进行计算，进而计算出整个系统的失效概率，并且利用MATLAB程序以及ANSYS中的APDL语言编写了JC法计算程序。计算结果表明，一般情况下层合板首先出现基体损伤失效，然后才会出现纤维断裂失效。这一结果与一些文献中的试验结果相一致，表明这种概率分析方法可以应用于实际复合材料层合板结构的可靠性分析。     

基于均匀设计的临近空间无动力攻击器运动参数响应面建模

为探求临近空间无动力攻击器运动参数的解析模型，采用均匀设计试验方法，以攻击器发射参数为设计变量，从设计空间中选择一些特定的设计点，构造了临近空间攻击器速度、射程以及飞行时间的响应面模型。通过仿真算例，对各响应面模型分别进行显著性检验，证明了所建立的响应面都具有较高的近似精度。     

固体发动机星形药柱的形状优化分析

为了极大地提高发动机的结构完整性能,利用MSC.Nastran软件的结构优化功能,对星形药柱发动机进行了形状优化分析.探讨了发动机形状优化中位移模式和辅助模型的建立方法,根据发动机的结构和受力特点,建立了星形药柱的平面应变模型,对星形药柱的控制参数进行了灵敏度分析,并在此基础上对星形药柱进行了形状优化.优化结果表明:增大星边夹角和顶弧倒角可有效地缓解应力应变的集中程度.     

复合战斗部爆炸成型弹丸结构参数影响分析

应用AUTODYN仿真软件,对一种复合战斗部方案的爆炸成型弹丸成型性能进行了分析,结果表明,相对于传统布局方案,破片方案更改后改变了药型罩的成型过程,导致爆炸成型弹丸形状变差从而降低了毁伤性能。通过对结构参数影响进行分析,提出了优化方案,解决了破片方案调整后爆炸成型弹丸的成型问题。     

基于CAS理论的海上编队作战指挥优化控制问题研究

针对当前提高基于信息系统的体系作战能力客观要求,运用复杂自适应系统理论分析了信息化条件下的海上编队作战指挥控制问题,提出了基于CAS理论的海上编队作战指挥优化控制结构模型,并给出了信息化条件下编队指挥所的作战指挥决策流程,从而为有效构建信息化编队作战指挥体系、提高作战指挥能力奠定了理论基础。     

ADAMS的全地形车载火箭炮行进间发射动力学研究

利用多体动力学软件ADAMS、有限元分析软件ABAQUS建立了全地形车载火箭炮系统发射与行驶一体化动力学模型,基于路面功率谱密度函数和谐波叠加法,创建了全地形车野外行驶的三维随机土石路况模型,对战车行进间发射进行了动力学仿真。分析该型号车载火箭炮行进间发射的动力学特性,得到了战车及发射装置的动态响应情况及运动特性和车速对发射的影响规律。仿真结果表明,全地形车可以在土石路况低速行驶完成行进间发射任务。     

弹药生产响应能力综合评价指标权重组合方法

针对战时弹药需求的不确定性而造成对生产能力冲击的特点,为科学地确定综合评价指标权重,评价军工企业弹药生产响应能力,运用基于偏差平方和最小的综合评价指标粗糙集与网络分析法的权重组合算法,将定性与定量评价方法相结合,为客观评价企业弹药生产响应能力提供了科学的依据,对提高弹药生产决策的军事经济效益具有重要的意义。     

泵喷推进器线谱非定常推力预报方法与试验验证

为预报泵喷推进器转子与周期性前导叶尾流互作用线谱非定常推力,忽略泵喷推进器转子叶片厚度,将泵喷转子简化为环形叶栅,根据片条理论,在半径r处截取泵喷转子分段,忽略流场参数沿分段径向的变化,从而可将该环形叶栅分段视为平面叶栅,在平面叶栅与简谐波互作用的基础上考虑周期性进流,推导得到前导叶分段与转子分段互作用线谱非定常激振力,转子分段周向积分得到非定常推力线谱预报公式,通过数值和试验方法验证公式的有效性。开展设计参数影响分析,得到当前导叶-转子间距与前导叶弦长的比值大于1时,转子-后导叶间距对转子单个叶片的激振力线谱推力几乎不存在影响。     

Resistance of grid steel-tube-confined concrete targets against projectile impact: Experimental investigation and analytical engineering model

Steel-tube-confined concrete (STCC) targets are provided with excellent anti-penetration performance over semi-infinite concrete (SIC) targets since the steel tube imposes passive restraint on the in-filled concrete during the penetration process. Grid STCC system with square steel tubes is a potential solution to protective structures. In this paper, experiments of 9-cell grid STCC targets penetrated by 12.7 mm Armor Piercing Projectile (APP) were performed. The influence of side length and thickness of steel tube, steel ratio and impact velocity on anti-penetration performance were taken into account. Additionally, single-cell square STCC targets were also designed and tested for comparison with the 9-cell grid STCC targets. Damage modes and parameters of the tested targets were measured and discussed. Moreover, the stiffness of radial confinement of grid STCC targets is achieved according to the elastic solution of infinite cylindrical shell in Winkler medium. Furthermore, the penetration resistance and depth of penetration (DOP) for grid STCC targets are obtained on the basis of the dynamic finite spherical cavity-expansion (FSCE) models including radial confinement effect. It is shown that the 9-cell grid STCC targets with optimal dimension match of thickness and side length of steel tube can reduce the DOP by about 17 % and 23 % in comparison with the SIC targets and single-cell square STCC targets, respectively, due to both the confinement of square steel tube to concrete in the impacted cell and the additional confinement of the surrounding cells to the impacted cell; the penetration resistance and DOP of the grid and cellular STCC targets with similar steel ratio is close, and thus the grid STCC targets with simpler manufacturing process and excellent in-plane expandability are preferred in engineering practice; moreover, the predicted results of DOP model based on the FSCE models agree well with the tested results with the maximum disparity less than 12 % and the proposed model is more applicable to the grid and cellular STCC targets with high radial confinement.