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基复板间距对爆炸焊接质量影响的数值模拟 被引量:12
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作者 缪广红 马雷鸣 +4 位作者 吴建强 刘丰茂 陈烨开 马宏昊 沈兆武 《爆破》 CSCD 北大核心 2020年第2期106-114,共9页
为了研究间距对爆炸焊接质量的影响,选取厚度为2 mm的钛板和钢板以2.5、4.5、6.5、8.5、10.5 mm为间距,借助有限元软件LS-DYNA,采用SPH-FEM耦合的方法,对爆炸复合过程做了三维数值模拟。结合材料参数计算并建立了爆炸复合窗口。模拟结... 为了研究间距对爆炸焊接质量的影响,选取厚度为2 mm的钛板和钢板以2.5、4.5、6.5、8.5、10.5 mm为间距,借助有限元软件LS-DYNA,采用SPH-FEM耦合的方法,对爆炸复合过程做了三维数值模拟。结合材料参数计算并建立了爆炸复合窗口。模拟结果显示:随着基复板间距的增大,焊接界面结合强度呈由低到高、由高到低的变化过程,与实验结果相吻合。当间距为6.5 mm时,碰撞速度的模拟结果接近爆炸复合窗口内的最大值,表明此时结合质量较好,模拟结果与实验吻合较好。借助SPH法得到了复合板结合面的界面形貌,模拟结果与实验的金相结果一致性较好,模拟结果显示在间距为6.5~8.5 mm之间时,能够得到较好的爆炸焊接界面波形。 展开更多
关键词 爆炸焊接 钛-钢 间隙 数值模拟
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基于风速估计的风力机状态反馈滑模容错控制 被引量:4
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作者 马磊明 肖玲斐 姜斌 《控制理论与应用》 EI CAS CSCD 北大核心 2022年第3期480-490,共11页
针对风力机变桨距执行机构突变故障,提出了基于风速估计的自适应状态反馈滑模容错控制策略.首先,设计了基于自适应状态反馈滑模理论的鲁棒主动容错控制器,并结合全阶补偿器对控制律进行设计;然后,利用基于变速灰狼优化算法的组合径向基... 针对风力机变桨距执行机构突变故障,提出了基于风速估计的自适应状态反馈滑模容错控制策略.首先,设计了基于自适应状态反馈滑模理论的鲁棒主动容错控制器,并结合全阶补偿器对控制律进行设计;然后,利用基于变速灰狼优化算法的组合径向基函数神经网络实现风速估计,可以改善风速测量精度并提高控制系统可靠性;最后,根据线性矩阵不等式和Lyapunov理论对控制器稳定性进行讨论,并与现有控制策略进行比较.仿真结果表明,在健康/故障的变桨距执行机构条件下,所提容错控制方法均能获得较好的控制效果. 展开更多
关键词 风速估计 径向基函数神经网络 风力机 滑模容错控制 自适应控制
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Study on Statistical Forecast Method for O_3 Concentration near the Ground in Pudong District of Shanghai Based on Meteorological Condition Analysis 被引量:1
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作者 ma Jing-hui ma lei-ming +3 位作者 GENG Fu-hai TAN Jian-guo GAO Wei ZHOU Wei-dong 《Meteorological and Environmental Research》 CAS 2012年第12期54-59,67,共7页
[Objective] The research aimed to study statistical forecast method for O3 concentration near the ground in Pudong District of Shanghai based on meteorological condition analysis. [Method] Via observation and statisti... [Objective] The research aimed to study statistical forecast method for O3 concentration near the ground in Pudong District of Shanghai based on meteorological condition analysis. [Method] Via observation and statistical analysis of the O3 concentration near the ground in Pudong District of Shanghai from 2006 to 2008, by considering meteorological condition, a kind of simple and practical new method suiting for forecast of the O3 concentration and pre-warning of the high-concentration O3 pollution event in whole year was established. [Result] Meteorological condition had obvious influence on O3 concentration near the ground. O3 concentration was the biggest in sunny day, followed by cloudy day. O3 concentration near the ground had typical seasonal change characteristics, and high value mainly happened in summer. Meteorological condition generating high-concentration O3 included sunny day, strong UV radiation, low relative humidity, high temperature and small wind speed, etc. By surveying historical weather chart, 10 kinds of main weather situations affecting Shanghai were summed. Under each weather situation, occurrence probability of the high-concentration O3 near the ground and average O3 concentration were conducted statistics. We found that occurrence probability of the high-concentration O3 was the biggest under northwest side of the subtropical high type, followed by internal type of the subtropical high. By introducing HPPI and WDI and comprehensively considering various meteorological factors, forecasting equation of the O3 concentration was established based on stepwise regression. The equation had good fitting effect and predictability on the daily maximum O3 concentration. [Conclusion] The method also could provide reference for O3 forecast in other areas. 展开更多
关键词 O3 concentration Meteorological condition Weather situation FORECAST China
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