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The penetration behavior and perforation characteristics of Kevlar/Epoxy laminates with various thickness in quasi-static and ballistic perforation penetrated by steel projectiles with different noses are investigated. Quasi-static tests are conducted on MTS810 testing system. The results indicate that global deformation is the major mechanism of energy absorption and woven laminates exhibit larger energy dissipation than that of angleplied laminates. Therefore, the woven laminates have better quasi-static penetration resistance. Ballistic tests with velocity of 200 - 700 m/s are executed by using a powder gun with 7.62 mm barrel. Comparing ballistic experimental results with those under quasi-static condition, both the perforation performance and the failure modes are related closely to the speed of penetrator. Quite different from quasi-static tests, ballistic tests indicate that thick angle-plied laminate targets are even better than woven laminates in resisting ballistic impact. It is observed that the damage zone of the laminate is localized highly with the increasing of the impact velocity and correspondingly, the failure modes are more manifold. The shape of projectile noses affects the impact resistance of laminated Kevlar significantly in the range of velocity around the ballistic limit. 相似文献
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王元博 《中国石油和化工标准与质量》2011,31(6):160
喇嘛甸油田进入特高含水期后,低产低效井井数呈逐年上升的趋势,截止2007年底水驱共有产量小于2吨的低产低效井395口,这些井制约着油田开发后期的经济效益以及全油田产量的顺利完成。本文在油层精细描述和储层内部结构界面研究成果的基础上,深入分析了油层剩余油的分布规律特征、动用程度,加强措施井选井选层方法研究,并通过补孔、压裂等增产措施挖潜油层剩余油,提高储层动用程度,达到了综合治理低产能恢复上产的目的。 相似文献
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选用常见的厨房布局,运用CFD数值模拟方法,模拟厨房空间在一定热羽流上升速度下温度场和速度场分布,研究不同通风工况下烹饪人员面部温度场变化。通过对比不同工况,得出烹饪时打开窗户会一定程度改善室内的热环境,烹饪人员面部区域温度最佳。 相似文献
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针对异步电网发生全网大停电后的恢复问题,提出一种并行协调恢复策略的优化制定方法。采用串并行思想,通过高压直流协调送、受端电网,并最终实现全网恢复。基于各交流子网的送、受端角色定位,分析各换流站的电源、负荷特性。建立异步电网并行协调恢复的优化模型,重点研究直流与送、受端电网的协调恢复过程。采用多种群遗传算法求解,得到最优恢复方案并确定直流的最佳启动时机。基于IEEE 39节点系统构建异步电网算例,对所提方法进行验证。结果表明,该优化方法具有可行性,适用于异步电网恢复方案的制定。 相似文献
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