CJ818中央翼盒复合材料结构设计及分析

中央翼盒是飞机主要的承力结构,承担着飞机起飞、巡航和着陆过程中机翼及机身传来的各种载荷。复合材料作为一种优良的航空材料,具有比强度高、比刚度大,材料力学性能可设计等优点;由于复合材料各向异性的特点,使其结构设计比金属结构更为复杂。对CJ818飞机的中央翼盒进行复合材料结构设计,强度校核后对复合材料结构设计进行优化。对比中央翼盒复合材料结构设计与金属结构设计,为我国大飞机中央翼盒结构设计做一些探索性的工作。     

CJ828中央翼盒复合材料结构设计

中央翼盒是飞机主要的承力结构,承担着飞机起飞、巡航和着陆过程中机翼及机身传来的各种载荷[1].复合材料作为一种优良的航空材料,具有比强度高、比刚度大、材料力学性能可设计等优点;由于复合材料各项异性的特点,使其结构设计比金属结构更为复杂.对CJ828飞机的中央翼盒进行复合材料结构设计,强度校核后对复合材料结构设计进行优化.对比中央翼盒复合材料结构设计与金属结构设计,为我国大飞机中央翼盒结构设计做一些探索性工作.     

如火如荼 380部件的生产进入高潮

A380飞机部件的制造是在2002年1月在法国南方的南特的工厂拉开序幕的。该工厂主要制造铝制的机翼-机身结合部位的翼根整流罩和用碳纤维增强塑料制造机翼中央翼盒。目前,南特工厂已经同时有5个A380中央翼盒正在组装。A380的中央翼盒长7米,宽6米,高2米,重12吨。     

复合材料结构件制造技术

作为大飞机关键制造技术之一,复合材料结构件制造技术已经广泛应用于飞机机翼、机身、垂尾、整流罩、中央翼盒等各个关键部位。随着国产大飞机项目的不断进展,复     

波音完成787梦想飞机翼盒的破坏性试验

日前,波音完成了787梦想飞机全尺寸复合材料翼盒的破坏性试验,这也是波音首次为民用飞机制造全复合材料的翼盒。此次试验是全新787飞机认证流程的一部分。翼盒是将机翼与机身相连接的悬臂梁,能支撑前缘和后缘装置、操纵舵面、发动机以及起落架。试验结构件为机翼段的一部分,长度约为15.2m。机翼上部、下部面板和翼梁全部由与机身相同的复合材料制成。翼肋为单块铝结构,     

大型飞机机身垂直入水冲击特性数值研究

针对带有中央翼盒的某型飞机的机身,数值研究了不同入水速度、姿态角和尾翘角对入水过程中机身压强和冲击力的影响规律。数值模拟中,控制方程选为非定常可压缩流动的雷诺时均Navier-tokes方程(RANS)和实现的k-ε模型,使用体积分数(VOF)方法捕捉水气交界面的变化,采用整体动网格技术来模拟机身相对于水面的运动。结果分析表明:机身入水过程中压强峰值首先出现在喷溅根部,随后转移至机身底部;入水初期机身冲击力系数迅速增大,而后略有回落,入水后期由于中央翼盒冲击水面会导致冲击力系数再次迅速增大,而后小幅震荡。速度越大、姿态角越大、尾翘角越小,机身冲击力系数越小。     

中美合作项目MD90-30干线飞机机身前段交付

6月1日,西安飞机工业(集团)有限责任公司为中美合作项目MD90-30干线飞机机身前段举行交付仪式。 MD90-30机身前段长9m、宽3.5m、高4m、重量达1309kg,这是继西飞1996年交付机翼翼盒大部件后,西飞向上海飞机     

CJ828龙骨梁结构设计

介绍了波音系列和空客系列飞机典型龙骨梁的结构特点,并针对双通道300座CJ828客机的具体要求,设计了双梁盒式结构龙骨梁.合理地选择了各零部件材料,详细设计了中央翼盒盒段和主起落架舱盒段,并对龙骨梁零部件间的连接形式进行了设计,最后通过分析计算机身和龙骨梁的外载,对龙骨梁进行了结构分析,结果表明所设计龙骨梁的强度满足设计要求.     

波音如何处理787研制过程中的结构损伤

<正>供应链的不到位和技术上的不成熟是波音787项目屡屡延期的主要原因。本文对波音787研制过程中出现的结构损伤特征、原因和修改方案进行了分析。2009年5月,波音在波音787机体静力试验中首次发现存在结构损伤问题,并对其进行修复。修复的部位集中在机身的两侧,即11段(中央翼盒)及12段(翼盒)上部结构的汇合处。     

机翼盒段结构优化分析

机翼在飞机飞行过程中产生升力,是飞机能够飞行的根本保障。翼盒是机翼的主要承力部件,承受机翼上产生的所有载荷。所以翼盒的结构设计,对机翼甚至整个飞机的影响有着至关重要的作用。好的结构设计不仅能够保证机翼产生正常的气动升力,以及机翼内系统的正常运作,而且能够充分发挥材料的性能优势,减轻结构重量。因此,结构优化设计技术开始广泛被使用。总结翼盒优化的工作,包括不同的结构布局形式,不同的气动压心位置,不同的发动机吊挂位置以及翼盒不同位置的结构尺寸优化,分析影响翼盒结构设计的因素,为机翼结构的初步设计打好基础。     

The effect of inlet conditions on the flow and heat transfer in multiple rotating cavity with axial throughflow

This paper discusses experimental results from two different build configurations of a heated multiple rotating cavity test rig.Measurements of heat transfer from the discs and tangential velocities are presented.The test rig is a 70% full scale version of a high pressure compressor stack of an axial gas turbine engine.Of particular interest are the internal cylindrical cavities formed by adjacent discs and the interaction of these with a central axial throughflow of cooling air.Tests were carried out for a range of non-dimensional parameters representative of high pressure compressor internal air system flows(Re up to 5×106 and Rez up to 2×105).Two different builds have been tested.The most significant difference between these two build configurations is the size of the annular gap between the(non-rotating) drive shaft and the bores of the discs.The heat transfer data were obtained from thermocouple measurements of surface temperature and a conduction solution method.The velocity measurements were made using a two component,LDA system.The heat transfer results from the discs show differences between the two builds.This is attributed to the wider annular gap allowing more of the throughflow to penetrate into the cavity.There are also significant differences between the radial distributions of tangential velocity in the two builds of the test rig.For the narrow annular gap,there is an increase of non-dimensional tangential velocity V/Ωr with radial location to solid body rotation V/Ωr=1.For the wider annular gap,the non-dimensional velocities show a decrease with radial location to solid body rotation.      

Research on Auto-detection for Remainder Particles of Aerospace Relay Based on Wavelet Analysis

Aerospace relay is one kind of electronic components which is used widely in national defense system and aerospace system. The existence of remainder particles induces the reliability declining, which has become a severe problem in the development of aerospace relay. Traditional particle impact noise detection (PIND) method for remainder detection is ineffective for small particles, due to its low precision and involvement of subjective factors. An auto-detection method for PIND output signals is proposed in this paper, which is based on direct wavelet de-noising (DWD), cross-correlation analysis (CCA) and homo-filtering (HF), the method enhances the affectiv-ity of PIND test about the small particles. In the end, some practical PIND output signals are analysed, and the validity of this new method is proved.     

Preparation of Highly Dispersed Antimony-doped Tin Oxide Nano-powder via Ion-exchange Hydrolysis of SnCl4 and SbCl3 and Azeotropic Drying

Antimony-doped tin hydroxide colloid precipitates have been synthesized by hydrolysis of SnCl4 and SbCl3 using: (1) an ion-exchange hydrolysis to remove chlorine ions, and (2) isoamyl acetate as an azeotropic solvent to obviate water. The obtained dried powder is of high dispersivity without any need for further grinding. The size and dispersivity of the final particles are investigated with the aid of TG-DTA, BET, XRD and TEM. After having calcined, the antimony-doped tin oxide nanopowder possesses a tetragonal rutile structure with high dispersivity, uniform particles and low hard agglomeration.     

Effects of Mo on the Microstructure and Hydrogen Sorption Properties of Ti-Mo Getters

The effects of Mo on the microstructure evolution, porosity and hydrogen sorption properties of Ti-Mo getters are investigated in this work. The results show that the addition of Mo prolongs the densification process of Ti-Mo getters and results in a significant amount of sintered pores. With the Mo content increasing, the porosity of getters firstly increases reaching the maximum value as it at- tains about 7.5wt.%, and then drops. At the room temperature, the hydrogen sorption property of getters increases progressively with the Mo content increasing, but the tendency is not very clear before its content lies below 2.5wt.%. When the Mo content achieves about 7.5wt.%, the hydrogen sorption property proves to be the best. The discussion is made about the above mentioned phenomena inclusive of hydrogen sorption properties of getters under different activation conditions (from 500-750 ℃).     

超声速燃烧数值模拟中的湍流与化学反应相互作用模型

高精度数值模拟有助于理解超声速湍流燃烧中湍流与化学反应的相互作用,可为发动机燃烧室等工程应用设计提供可靠的预测模型。除直接数值模拟外,目前在湍流燃烧应用中使用的大涡模拟和雷诺平均Navier-Stokes模拟均需要借助模型模化发生在湍流小尺度上的流动与化学反应过程对湍流大尺度运动的影响。现有的湍流与化学反应相互作用模型大致可分为:火焰面类模型和概率密度函数类模型,2类模型在不同的应用中各自具有优势和局限性。此外,现有模型大都基于低马赫数燃烧,而超声速燃烧中通常会伴随快速混合、局部熄火和再着火以及激波等复杂过程,这为发展其中的湍流与化学反应相互作用模型提出了更多的挑战。     

适于低轨卫星IP网络的单核共享树组播算法(英文)

为了解决低轨卫星IP网络中现有典型源组播算法的信道资源浪费问题,本文提出了一套单核共享树组播算法,即核心群合并共享树(CCST)和加权核心群合并共享树(w-CCST)算法。CCST 算法包括动态近似中心(DAC)选核方法和核心群合并组播路径构建方法。DAC方法专为周期、规律运动的低轨卫星网络提出,不需要复杂的星上计算。在核心群合并方法中,以核节点作为初始核心群,通过核心群和剩余组成员的最短路径方法逐步扩展直至整棵组播树构建完成,从而使得组播树的树代价最小,大大提高了网络的带宽利用率和组播传输效率。w-CCST 算法中所提出的加权因子可以调整树代价和端到端传播时延之间的折衷程度,因此,可以通过调整加权因子来适度增大树代价、降低端到端传播时延以支持某些端到端时延要求苛刻的实时组播业务。最后,与低轨卫星 IP 网络中典型算法进行了性能比较,仿真结果说明,CCST 算法的平均树代价比其它算法显著降低,w-CCST 算法的平均端到端传播时延小于 CCST 算法。     

Jet Vectoring Control Using a Novel Synthetic Jet Actuator

A primary air jet vectoring control system with a novel synthetic jet actuator (SJA) is presented and simulated numerically. The results show that, in comparison with an existing traditional synthetic jet actuator, which is able to perform the duty of either “push” or “pull”, one novel synthetic jet actuator can fulfill both “push” and “pull” functions to vector the primary jet by shifting a slide block inside it. Therefore, because the new actuator possesses greater efficiency, it has potentiality to replace the existing one in various appli- cations, such as thrust vectoring and the reduction of thermal signature. Moreover, as the novel actuator can fulfill those functions that the existing one can not, it may well be expected to popularize it into more flow control systems.     

Nonlinear Adaptive Slewing Motion Control of Spacecraft Truss Driven by Synchronous V-gimbaled CMG Precession

The slewing motion control of a truss arm driven by a V-gimbaled control-moment-gyro (CMG) is a nonlinear control problem. The V-gimbaled CMG consists of a pair of gyros that must precess synchronously. The moment of inertia of the system, the angular momentum of the gyros and the external disturbances are not exactly known. With the help of feedback linearization and recursive Lyapunov design method, an adaptive nonlinear controller is designed to deal with the unknown items. Performance of the proposed controller is verified by simulation.     

An SOR Implicit Time-accurate Scheme in Calculating Unsteady Flows

A new time-accurate marching scheme for unsteady flow calculations is proposed in the present work. This method is the combination of classical Successive Over-Relaxation (SOR) iteration method and Jacobian matrix diagonally dominant splitting method of LUSGS. One advantage of this algorithm is the second-order accuracy because of no factorization error. Another advantage is the low computational cost because the Jacobian matrices and fluxes are only calculated once in each physical time step. And, the SOR algorithm has better convergence property than Gauss-Seidel. To investigate its accuracy and convergency, several unsteady flow computa- tional tests are carried out by using the proposed SOR algorithm. Roe’s FDS scheme is used to discritize the inviscid flux terms. Un- steady computational results of SOR are compared with the experiment results and those of Gauss-Seidel. Results reveal that the numerical results agree well with the experimental data and the second-order accuracy can be obtained as the Gauss-Seidel for unsteady flow computations. The impact of SOR factor is investigated for unsteady computations by using different SOR factors in this algorithm to simulate each computational test. Different numbers of inner iterations are needed to converge to the same criterion for different SOR factors and optimal choice of SOR factor can improve the computational efficiency greatly.