铺层顺序对复合材料层合结构承载的影响

 针对连接区常用的铺层比例[0/±45/90]=(50:40:10),选择3种常见的铺层顺序,综合研究铺层顺序对层合结构承载能力的影响。被研究的层合结构的承载能力包括光滑拉伸和压缩强度、圆孔拉伸和压缩强度、及螺栓连接强度。研究结果表明,各种方向铺层均匀散开铺叠的层合板,在多数情况下性能最优,承载能力最好;将90°层置于外表面的层合板,所试各种试件的承载能力都是最差的。±45°层成对铺贴则压缩强度较差。     

三维编织C／SiC复合材料剪切和压缩性能的试验研究

对三维编织C/SiC复合材料进行剪切试验和压缩试验,得到两组试验的载荷位移曲线以及剪切强度和压缩强度.实验发现,相同宽度的剪切试件,剪切厚度小的试件剪切强度比剪切厚度大的试件高;相同剪切截面的剪切试件,XY剪切强度高于YX剪切强度;横截面积相同,高度不同的压缩试件在X方向的压缩强度相差不大.对三维编织C/SiC复合材料热端构件进行分析,结果表明,构件的压缩强度和剪切强度都能满足强度要求.     

含缺陷复合材料层压板的压缩破坏机理

 本文综述了含缺陷(包括孔及冲击损伤)复合材料层压板在压缩载荷作用下的破坏机理及破坏模式,特别是对层压板构成最大威胁的低能量冲击损伤机理及压缩破坏模式作了比较深入的论述,总结出了四种破坏模式,并从分层断裂力学的观点出发给出了解决含低能量冲击损伤层压板的压缩剩余强度估算的途径。     

共用支承-转子系统耦合振动分析及试验

针对带有涡轮级间共用承力框架的高功质比涡轴发动机结构系统,建立共用支承-转子系统动力学方程,探究燃气发生器转子、动力涡轮转子与共用承力框架结构系统耦合振动产生条件及振动特性。基于ANSYS有限元仿真计算了共用支承-转子系统耦合振动特性。针对涡轴发动机涡轮级间承力框架,设计了共用支承-转子系统模拟试验器,运用激振器模拟转子不平衡激励,利用试验对模拟转子动力特性的相互影响进行了定量分析。理论计算结果表明,转子支点与支承结构通过力平衡和位移协调联系在一起,之间存在刚度耦合项,进而使共用支承-转子系统发生耦合振动。对系统振动响应仿真计算结果表明,共用支承会影响转子动力特性,不同转子不平衡激励均可激起相应转子的振动。通过试验验证了在发生耦合振动时,转子的振动响应频谱中同时包含两个转子转速频率,定义耦合影响系数,地面慢车状态两个转子相互之间的耦合影响系数分别为33%和6079%,最大连续状态分别为1278%和688%,最大起飞状态分别为1356%和581%,转子间的动力特性耦合影响大小与频率有关系。     

绕水翼超空化阶段汽液混合体动态特性的实验观测

为深入了解超空化流动机理,采用高速录像和数字粒子图像测速系统( DPIV)对绕hydronautics水翼的超空化流场进行了观测.结果表明:在两相共存超空化阶段,水汽混合相和汽相的分布决定了超空化区域速度场和涡量场的分布特性;水汽混合区的速度相对较低,而汽相区则与主流区有着相近的速度分布,而且空化区与主流区交界面处有着较大的速度梯度;在水汽混合区与主流区的交界处形成了上下涡带,其涡量分布表现出了明显的时间依赖性.     

Generation of Accelerated Stability Experiment Profile of Inertial Platform Based on Finite Element

The residual stress generated in the manufacturing process of inertial platform causes the drift of inertial platform parameters in long-term storage condition.However,the existing temperature cycling experiment could not meet the increased repeatability technical requirements of inertial platform parameters.In order to solve this problem,in this paper,firstly the Unigraphics(UG) software and the interface compatibility of ANSYS software are used to establish the inertial platform finite element model.Secondly,the residual stress is loaded into finite element model by ANSYS function editor in the form of surface loads to analyze the efficiency.And then,the generation based on ANSYS simulation inertial platform to accelerate the stability of experiment profile is achieved by the application of the analysis method of orthogonal experimental design and ANSYS thermal-structural coupling.The optimum accelerated stability experiment profile is determined finally,which realizes the rapid,effective release of inertial platform residual stress.The research methodology and conclusion of this paper have great theoretical and practical significance to the production technology of inertial platform.     

Investigation into Pilot Handling Qualities in Teleoperation Rendezvous and Docking with Time Delay

Teleoperation rendezvous and docking can be used as a backup for autonomous rendezvous and docking(RVD) for an unmanned spacecraft when the autonomous system is failure or for guiding the chaser docking with an uncooperative target.The theoretical model for analyzing the handling qualities in teleoperation RVD process is established based on the previous studies conducted by National Aeronautics and Space Administration(NASA).The predictive factor is introduced to describe the pilot’s predictive ability in the teleoperation tasks with time delay,which interrelates with the skills of a pilot and the predictive assist approach used in the tasks such as the predictive display method.Based on the semi-physical simulation system in our laboratory,900 experiments at two levels of time delay are carried out by 18 volunteers for validating the established model.The experimental results demonstrate the correctness of the theoretical model and indicate that a skilled pilot has a predictive ability of approximately 0.9 in teleoperation RVD tasks.The theoretical analysis shows that the handling qualities are greatly affected by the time delay and the predictive factor,and it is impossible to achieve a teleoperation RVD task for the skilled pilot when the time delay is larger than 9.0 s.     

降雨对飞机气动性能影响的研究综述

研究了降雨的自然特性,分析了降雨条件下机翼表面复杂的物理现象.重点从实验测试和数值模拟两方面论述了国内外关于降雨对飞机气动性能影响的研究进展,内容涉及降雨条件下机翼的气动性能损失、降雨对机翼气动性能的影响机理和机翼对各种影响因素的敏感度研究等方面.指出了当前国内外关于这一研究在自然飞行测试、实验相似准则、风洞实验中边界层固定转捩和多相流数值建模等方面所面临的关键问题和重大技术挑战.      

流场特性预测的两类高效方法

在多因素多水平试验设计方法建立数据库的基础上,提出了预测流场特性的两类高效方法:一类是响应面方法;一类是小波神经网络方法.典型算例表明,两类方法都可以高效率的获取流场特性参数,而且在预测的精度与计算的效率上,小波神经网络方法较响应面方法更具有优势.      

气氧/丙烷小推力发动机设计与实验

为适应小推力发动机无毒、无污染、高性能、低成本的发展趋势,设计了一种以气氧(GO₂)/丙烷(C₃H₈)为推进剂的发动机.采用层板式头部喷注器、利用喷嘴间隙实现电火花点火的独特点火方案、通过边区喷嘴进行气膜冷却,同时设计了发动机实验系统并开展了初步实验研究.实验结果表明:实验系统设计合理;发动机点火方案可靠、燃烧稳定、热防护效果良好,为进一步的研究奠定了基础.