Collisions between birds and aircraft are one of the most dangerous threats to flight safety. In this study, smoothed particles hydrodynamics(SPH) method is used for simulating the bird strike to an airplane wing lead...Collisions between birds and aircraft are one of the most dangerous threats to flight safety. In this study, smoothed particles hydrodynamics(SPH) method is used for simulating the bird strike to an airplane wing leading edge structure. In order to verify the model, first, experiment of bird strike to a flat aluminum plate is simulated, and then bird impact on an airplane wing leading edge structure is investigated. After that, considering dimensions of wing internal structural components like ribs, skin and spar as design variables, we try to minimize structural mass and wing skin deformation simultaneously. To do this, bird strike simulations to 18 different wing structures are made based on Taguchi’s L18 factorial design of experiment. Then grey relational analysis is used to minimize structural mass and wing skin deformation due to the bird strike. The analysis of variance(ANOVA) is also applied and it is concluded that the most significant parameter for the performance of wing structure against impact is the skin thickness. Finally, a validation simulation is conducted under the optimal condition to show the improvement of performance of the wing structure.展开更多
基于多目标在区域尺度实现河套灌区秋浇模式的优化对保证灌区粮食安全、用水安全和生态安全具有重要意义。基于率定验证后的分布式SWAP-WOFOST模型对2000-2017年河套灌区不同秋浇模式和种植条件下的模拟结果,以作物产量、水分生产力(Wat...基于多目标在区域尺度实现河套灌区秋浇模式的优化对保证灌区粮食安全、用水安全和生态安全具有重要意义。基于率定验证后的分布式SWAP-WOFOST模型对2000-2017年河套灌区不同秋浇模式和种植条件下的模拟结果,以作物产量、水分生产力(Water Productivity,WP)、地下水埋深(Groundwater Depth,GWD)、土壤含水量(Soil Water Content,SWC)和土壤含盐量(Soil Salt Content,SSC)为评价指标,通过AHP-CRITIC-熵值法-TOPSIS综合评价法,分别对河套灌区3种主要作物(春小麦、春玉米和向日葵)种植条件下适宜的秋浇模式进行优选和评价,并对3种主要作物在推荐秋浇模式下的种植结构进行初步区划。结果显示:在推荐的秋浇模式下河套灌区3种作物的多年平均产量分别为4945、8332和3496 kg/hm^(2),多年平均WP分别为1.15、1.82和1.04 kg/m^(3),节省秋浇引黄灌溉水量约14.8%~30.7%。基于推荐的秋浇模式区划后春小麦、春玉米和向日葵的种植面积分别占灌区总面积的21.1%、37.8%和41.1%,在此种植结构下可节省约3.04亿m^(3)的秋浇引黄灌溉水量。展开更多
文摘Collisions between birds and aircraft are one of the most dangerous threats to flight safety. In this study, smoothed particles hydrodynamics(SPH) method is used for simulating the bird strike to an airplane wing leading edge structure. In order to verify the model, first, experiment of bird strike to a flat aluminum plate is simulated, and then bird impact on an airplane wing leading edge structure is investigated. After that, considering dimensions of wing internal structural components like ribs, skin and spar as design variables, we try to minimize structural mass and wing skin deformation simultaneously. To do this, bird strike simulations to 18 different wing structures are made based on Taguchi’s L18 factorial design of experiment. Then grey relational analysis is used to minimize structural mass and wing skin deformation due to the bird strike. The analysis of variance(ANOVA) is also applied and it is concluded that the most significant parameter for the performance of wing structure against impact is the skin thickness. Finally, a validation simulation is conducted under the optimal condition to show the improvement of performance of the wing structure.
文摘基于多目标在区域尺度实现河套灌区秋浇模式的优化对保证灌区粮食安全、用水安全和生态安全具有重要意义。基于率定验证后的分布式SWAP-WOFOST模型对2000-2017年河套灌区不同秋浇模式和种植条件下的模拟结果,以作物产量、水分生产力(Water Productivity,WP)、地下水埋深(Groundwater Depth,GWD)、土壤含水量(Soil Water Content,SWC)和土壤含盐量(Soil Salt Content,SSC)为评价指标,通过AHP-CRITIC-熵值法-TOPSIS综合评价法,分别对河套灌区3种主要作物(春小麦、春玉米和向日葵)种植条件下适宜的秋浇模式进行优选和评价,并对3种主要作物在推荐秋浇模式下的种植结构进行初步区划。结果显示:在推荐的秋浇模式下河套灌区3种作物的多年平均产量分别为4945、8332和3496 kg/hm^(2),多年平均WP分别为1.15、1.82和1.04 kg/m^(3),节省秋浇引黄灌溉水量约14.8%~30.7%。基于推荐的秋浇模式区划后春小麦、春玉米和向日葵的种植面积分别占灌区总面积的21.1%、37.8%和41.1%,在此种植结构下可节省约3.04亿m^(3)的秋浇引黄灌溉水量。
