风车载荷情况下民用飞机结构强度评定方法

按照适航要求,需要对风车载荷下民用喷气运输飞机结构强度进行评定。首先从静强度、疲劳强度、损伤容限的角度,介绍风车载荷下飞机结构强度的评定方法。以已经获得适航认可的分析方法为基础,根据各方法的特点,结合风车载荷情况的特点,进行合理改进,形成适用于风车载荷下飞机结构强度的评定方法。其次从基本剖面形式、修正参数、结构动力学建模方法、评定部位的筛选标准、评定结果的判据等方面进行介绍,并展示该评定方法的优点。最后简要说明其在型号上的应用情况及适航审查要求及结果,并提出该评定方法的改进建议。     

Changes in suspended sediments associated with 2004 Indian Ocean tsunami

The Sumatra tsunami on 26 December, 2004 in the Indian Ocean was generated by one of the largest earthquakes of the past 100 years. The present study investigated spatial and temporal changes of suspended sediment concentration (SSC) in North-East Indian Ocean (NEIO) after the Sumatra tsunami used satellite remote sensing data. The nLw551 products of MODIS-aqua data (using as indexing SSC) were analyzed for 5 years (2002–2006). Result shows SSC notably increased (55.6–200%) in large river estuaries along coast of the Bay of Bengal (BOB) in a short time (4 weeks) after the tsunami, especially the northwest coast of Indonesia, southeast coast of Myanmar, as well as the north offshore of BOB. Those increases were mainly caused by the re-suspension function induced by the initial surge of the tsunami. Monthly analysis indicates increases (4.26%) of SSC of the entire North-East Indian Ocean area in 2005; especially in November 2005 when increase of SSC increased by about 6.19% compared with other years; those may mainly be caused by the destruction of coastal vegetation and modifying of estuaries or wetlands by the 2004 tsunami. The increases of SSC have different mechanism in different region and period after the tsunami.     

APPLICATION OF HYBRID GENETIC ALGORITHM IN AEROELASTIC MULTIDISCIPLINARY DESIGN OPTIMIZATION OF LARGE AIRCRAFT

The genetic/gradient-based hybrid algorithm is introduced and used in the design studies of aeroelastic optimization of large aircraft wings to attain skin distribution,stiffness distribution and design sensitivity.The program of genetic algorithm is developed by the authors while the gradient-based algorithm borrows from the modified method for feasible direction in MSC/NASTRAN software.In the hybrid algorithm,the genetic algorithm is used to perform global search to avoid to fall into local optima,and then the excellent individuals of every generation optimized by the genetic algorithm are further fine-tuned by the modified method for feasible direction to attain the local optima and hence to get global optima.Moreover,the application effects of hybrid genetic algorithm in aeroelastic multidisciplinary design optimization of large aircraft wing are discussed,which satisfy multiple constraints of strength,displacement,aileron efficiency,and flutter speed.The application results show that the genetic/gradient-based hybrid algorithm is available for aeroelastic optimization of large aircraft wings in initial design phase as well as detailed design phase,and the optimization results are very consistent.Therefore,the design modifications can be decreased using the genetic/gradient-based hybrid algorithm.     

Preliminary Study on Magnetic Induction Intensity Induced by Plasma During Hypervelocity Impact

An experimental system has been built to produce and measure the magnetic field in the backward ejected matter during hypervelocity impact. The designs of measurement system and coil, the choice of associated equipment, and the system calibration are also described in detail. The measurement of magnetic induction intensity for different given coil positions and azimuth angles are performed with two-stage light-gas gun. On condition that impact velocities are approximately equal and incidence angles are 45°, 60° and 90° respectively, the relationship between average magnetic induction intensity and impact angle at different time spans is obtained. Experimental results show that the average magnetic induction intensity with incidence angle of 90° is larger than those with incidence angles of 45°and 60°.     

先进复杂产品研制体系的分析

针对新时期大型复杂装备的研制特点,通过对先进设计技术的跟踪研究,分析国外复杂产品装备研制的先进设计技术、理论和方法,并结合典型应用案例深入研究先进设计技术在复杂产品研制中的应用,以帮助我国军工制造企业更好地理解和应用先进的综合设计技术。     

COMPASS/GPS双系统四星定位算法研究

针对COMPASS系统处于组网期,有效卫星缺失引起双系统卫星导航接收机暂时性无法定位的问题,提出一种双系统四星定位算法。利用完备条件下的定位信息,采用最小二乘拟合法或α-β滤波法,将完备条件下解算得到的COMPASS与GPS的系统钟差线性化,得到该钟差在非完备条件下的值,再结合可视卫星,在双系统四星条件下短时间内保持定位。算法无需引入其他设备,不依赖电子地图。经仿真验证,算法有效可行,在双系统四星条件下定位精度较高,且卫星信号恢复到完备条件后,定位精度能迅速恢复到完备条件下的水平。     

适应“主-供”新模式 积极做好机体制造供应商

认真思考、探索新模式下的双赢路径,利用新模式带来的机会,实现创新式的发展,让"主一供"模式的双方都实现企业实力更上一层楼,则应该是业界共同面临的课题,也是国人最期盼的结果.     

Modeling and initial assessment of the inter-frequency clock bias for COMPASS GEO satellites

The COMPASS system is a project established by China to develop an independent global satellite navigation system, which has five GEO (Geostationary Orbit) satellites and thirty Non-GEO satellites. An apparent inter-frequency clock bias (IFCB) for COMPASS GEO satellites is investigated using the real data. The bias also is modeled by the different models. Based on the 15 months (DOY 121, 2011–214, 2012) single-day-estimated results, the periodic variation of IFCBs of the COMPASS GEO satellite is studied using a harmonic analysis. The notable periods of 12 h and 8 h are noted. The harmonics-based models with different periods and different orders and quadratic function based model are used to describe the IFCB. The performances show that the 4-order harmonics-based model with the periods of 24, 12, 8 and 6 h is most optimal than others for describing the IFCB of COMPASS GEO satellite. Its amplitudes and phases estimated from a least square fit are used to study the features of the IFCB. The results show that the current amplitudes and phases do not present special features. Although the irregular amplitudes and phases of the model are disadvantageous for the long-term prediction of IFCB, it is obvious that the modeling IFCB can simple its service and a few of coefficients can replace the IFCB series. The performance of the model in short-term prediction IFCB is tested using the ten-day data (DOY 215-224, 2012).     

国际BOT投融资与项目选择的研究

从融资渠道、项目选择以及影响决策的政治、经济、效益、地域、周边环境诸因素分析国际ＢＯＴ投资模式，为我国对外经营公司以ＢＯＴ投资方式打入国际工程承包市场找准正确的切入点，以求在国际竞争中取得良好的经济效益。