全综合的舰队维修和支持数据库

由于海军进入了预算紧张和舰队大修和设备修复之间间隔增大的时代,中级维修机构(IMA)的工作量将增加。大多数修理和部件大修要求每个修理机构采用能产生最大效率和高质量修理的管理方法。本文将介绍目前管理的舰队维修,以及如何通过利用现有的或正在开发的方法和数据文件逐渐开发适合于从生产工人到高级管理人员所有参与者的主数据库。本文介绍了舰种司令(TyCom)、指挥的直接上级(ISIC)和IMA的接口以及利用主数据库工具进行计划和实施高质有效修理的舰船。同时还介绍了TyCom、NavSea(海军海上系统司令部)和造船厂之间的接口,以及有效地计划和调度仓库和中级修理时间,以满足现行预算和作战限制的要求。     

Evaluation of effectiveness of polymer coatings in reducing blast-induced deformation of steel plates

Incorporating elastomers such as polymers in protective structures to withstand high energetic dynamic loads, has gained significant interest. The main objective of this study is to investigate the influence of a Polyurea coating towards the blast-induced response in steel plates. As such, Polyurea coated steel plates were tested under near-field blast loads, produced by the detonation of 1 kg of spherical nitromethane charges, at a standoff distance of 150 mm. Mild steel (XLERPLATE 350) and high-strength steel (BIS80) plates with thicknesses of 10 mm were Polyurea coated with thicknesses of 6 mm and 12 mm on either the front (facing the charge) or the back face. The deformation profiles were measured using 3D scanning. Numerical simulations were performed using the non-linear finite element code LS-DYNA. The strain-dependent behaviour of the steel and Polyurea were represented by Johnson-cook and Money-Rivlin constitutive models, respectively. The numerical models were validated by comparing the plate deflection results obtained from the experiments and were then used in the subsequent parametric study to investigate the optimum thickness of the Polyurea coating. The results indicate that back face coating contributes towards an approximately 20% reduction in the residual deformation as well as the absence of melting of the Polyurea layer, while the front-face coating can be used a means of providing additional standoff distance to the steel plates.     

马里冲突暴露美国白宫和五角大楼的分歧

在马里不断扩大战争公开了白宫和五角大楼之间对于伊斯兰武装分子集团造成威胁程度的分歧。这些鱼龙混杂的武装分子和“基地”组织有着说不清道不明的联系。而这些威胁正严重地破坏着西非局势的平稳。尽管没有人表示这些武装分子集团已经对美国造成了紧迫的威胁。但是法国对马里的军事干预,以及发生在马里邻国阿尔及利亚针对国际天然气设施的恐怖袭击,引发了奥巴马政府对于这些武装分子集团是否已经对美国及其盟友的利益形成了足够的风险以至于要进行军事回应的激烈争辩。