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181.
某型军用履带车辆行驶强化试验仿真技术研究 总被引:2,自引:0,他引:2
以某型履带车辆为例,通过建立其虚拟样机,构造虚拟数字路面,进行履带车辆强化行驶试验仿真,获得零部件载荷时间历程。基于仿真结果,利用有限元与疲劳寿命分析软件,计算车辆零部件的疲劳寿命,再通过比较分析获得履带车辆在几个典型路面下的强化系数。研究结果对于新型履带车辆的开发及现役履带车辆维修保障具有参考价值。 相似文献
182.
含孔洞铜板复合材料修复疲劳寿命数值分析 总被引:1,自引:1,他引:0
用ANSYS有限元软件对复合材料修复含中心圆孔钢板的疲劳寿命进行了数值分析。研究了孔洞大小、补片长度、宽度和厚度对钢板疲劳寿命的影响;分析了复合材料胶接修补的效果,并对修复所用的复合材料补片的大小及厚度进行了优化设计。研究结果表明,利用复合材料胶接修补带中心圆孔的钢板可以使其疲劳性能提高1.6~18倍。修补时,增加补片宽度和厚度都可增加结构疲劳寿命;补片宽度为孔径8倍以上时,增加宽度对疲劳寿命影响不大;补片的长度为孔径的3~4倍时,修复效果最佳。 相似文献
183.
We consider a class of production scheduling models with m identical machines in parallel and k different product types. It takes a time pi to produce one unit of product type i on any one of the machines. There is a demand stream for product type i consisting of ni units with each unit having a given due date. Before a machine starts with the production of a batch of products of type i a setup cost c is incurred. We consider several different objective functions. Each one of the objective functions has three components, namely a total setup cost, a total earliness cost, and a total tardiness cost. In our class of problems we find a relatively large number of problems that can be solved either in polynomial time or in pseudo‐polynomial time. The polynomiality or pseudo‐polynomiality is achieved under certain special conditions that may be of practical interest; for example, a regularity pattern in the string of due dates combined with earliness and tardiness costs that are similar for different types of products. The class of models we consider includes as special cases discrete counterparts of a number of inventory models that have been considered in the literature before, e.g., Wagner and Whitin (Manage Sci 5 (1958), 89–96) and Zangwill (Oper Res 14 (1966), 486–507; Manage Sci 15 (1969), 506–527). © 2008 Wiley Periodicals, Inc. Naval Research Logistics, 2008 相似文献
184.
为了对含内聚空洞固体导弹发动机的贮存寿命进行预估,采用加速老化试验,得到该推进剂最大延伸率随贮存时间的变化规律;应用三维粘弹性有限元分析方法,对含内聚空洞的发动机贮存一定时间后直接点火发射过程进行数值仿真,从中获得发动机药柱在点火增压和轴向过载联合作用下的最大Von Mises应变.将不同贮存期药柱的最大Von Mises应变值与推进剂的最大延伸率进行对比,利用结构完整性评估准则,给出了某发动机药柱不同贮存期间内聚空洞大小的允许值.该方法可为含内聚空洞固体发动机的判废提供定量参考. 相似文献
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金属化膜电容器是惯性约束聚变激光装置能源系统最重要的元器件,对个体电容器的剩余寿命进行有效的预测对整个装置的可靠性水平有着重要的影响.为有效地预测个体电容器的剩余寿命,提出了融合单个电容器性能退化数据与先验性能退化数据信息的预测方法.采用Wiener过程对其性能退化过程进行建模,并根据先验退化数据信息构造参数的先验分布... 相似文献
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Keith Hartley 《Defence and Peace Economics》2013,24(3):445-459
A benefit‐cost framework and the associated evidence is used to evaluate UK arms exports. Two issues are examined in detail. First, trade externalities; and second, a case study of the problems and costs of maintaining the UK submarine industrial base without exports. 相似文献
190.
Current International Atomic Energy Agency safeguards do not provide adequate protection against the diversion to military use of materials or technology from certain types of sensitive nuclear fuel cycle facilities. In view of highly enriched uranium's relatively greater ease of use as a nuclear explosive material than plutonium and the significant diseconomies of commercial spent fuel reprocessing, this article focuses on the need for improved international controls over uranium enrichment facilities as the proximate justification for creation of an International Nuclear Fuel Cycle Association (INFCA). In principle, the proposal is equally applicable to alleviating the proliferation concerns provoked by nuclear fuel reprocessing plants and other sensitive nuclear fuel cycle facilities. The INFCA would provide significantly increased nonproliferation assurance to its member states and the wider international community by holding long-term leasehold contracts to operate secure restricted zones containing such sensitive nuclear facilities. 相似文献