超薄聚酰亚胺薄膜研究与应用进展

从制备工艺、应用进展以及发展趋势等方面综述超薄型聚酰亚胺薄膜近年来基础研究与应用的发展情况,着重介绍了超薄型聚酰亚胺薄膜在空间以及微电子领域的应用。最后,结合中国科学院化学研究所在超薄型聚酰亚胺薄膜领域内的研究进展,对发展我国的超薄型聚酰亚胺薄膜产业提出了建议。     

一种圆翼飞行器风洞实验与随动机制

阐述了圆翼随动机制的基本原理,研制了无人验证机,并进行了风洞实验研究。结果表明：可以绕 其圆心自由转动的圆形机翼（简称“圆翼”）能随其两侧气动阻力的不平衡而转动,从而消除翼 面上的侧滑效应。采用这种气动结构的飞机具有绕其立轴转动,在转弯时可实现机翼无倾斜 的航向机动能力。圆翼相对其任一轴线都是对称的。当机头偏离航向线而发生侧滑时,与机 身同轴的圆翼在气动阻力的作用下,向反方向转动,以新的纵轴对正航向,继续保持机 翼的气动平衡。     

A study of morphing aircraft on morphing rules along trajectory

Morphing aircraft can meet requirements of multi-mission during the whole flight due to changing the aerodynamic shape, so it is necessary to study its morphing rules along the trajectory. However, trajectory planning considering morphing variables requires a huge number of expensive CFD computations due to the morphing in view of aerodynamic performance. Under the given missions and trajectory, to alleviate computational cost and improve trajectory-planning efficiency for morphing aircraft, an offline optimization method is proposed based on Multi-Fidelity Kriging (MFK) modeling. The angle of attack, Mach number, sweep angle and axial position of the morphing wing are defined as variables for generating training data for building the MFK models, in which many inviscid aerodynamic solutions are used as low-fidelity data, while the less high-fidelity data are obtained by solving viscous flow. Then the built MFK models of the lift, drag and pressure centre at the different angles of attack and Mach numbers are used to predict the aerodynamic performance of the morphing aircraft, which keeps the optimal sweep angle and axial position of the wing during trajectory planning. Hence, the morphing rules can be correspondingly acquired along the trajectory, as well as keep the aircraft with the best aerodynamic performance during the whole task. The trajectory planning of a morphing aircraft was performed with the optimal aerodynamic performance based on the MFK models, built by only using 240 low-fidelity data and 110 high-fidelity data. The results indicate that a complex trajectory can take advantage of morphing rules in keeping good aerodynamic performance, and the proposed method is more efficient than trajectory optimization by reducing 86% of the computing time.     

基于模态滤波器的柔性智能桁架结构振动主动控制实验研究

基于模态滤波器技术和最优控制理论 ,在测量加速度的情况下 ,采用独立模态空间控制方法研究了空间柔性智能桁架结构的振动主动控制问题。在研制了智能桁架结构的基础上 ,基于计算机控制系统理论 ,采用加速度测量进行了柔性智能桁架结构的实时计算机振动主动控制实验研究。实验结果表明该控制方法是行之有效的     

控制力作用柔性喷管动力响应研究

选择某锥筒式扩张段柔性喷管作为目标,用弹簧模型取代柔性接头结构,运用结构动力有限元方法,纽马克差分格式,对结构模型进行了动力载荷作用下的响应分析,获得了三角波、正弦波和反正弦波三种激励下的结构响应结果。      

基于机敏材料的冗余度柔性机器人复模态主动控制

研究了基于机敏材料的冗余度柔性机器人的振动主动控制问题。应用复模态理论对机器人的动力学方程进行解耦 ,建立了受控系统的状态空间表达式。利用极小值原理设计了连续LQR状态反馈控制器 ,并根据对偶原理设计了具有指定稳定度的Luenberger全维状态观测器。平面 3R冗余度柔性机器人的仿真算例表明 ,该方法可以显著改善受控系统的动力学性能。     

破裂涡流中非定常现象与频率特性实验研究

通过流动显示、表面动态压力测量及热线测量等实验手段,对三角翼破裂涡流中的多种频率成分进行了分析。频谱分析确定了破裂点脉动和螺旋波的频率特征。实验结果表明,螺旋波主频随着弦向位置的增大先是迅速而后平缓减小。前缘涡破裂点振动具有准周期性,在不同的弦向位置上主频大小几乎没有改变,在靠近破裂点的位置有较大的振动能量。实验分析还表明,在破裂涡的流动状态下,虽然没有形成完全分离流,三角翼绕流流场中已经存在涡脱落的现象。     

Aerodynamic periodicity of transient aerodynamic forces of flexible plunging airfoils

For flapping micro-air vehicles, periodical aerodynamics in every plunging period is always desired in the design of aircraft controlling system. During the periodic plunges of rigid airfoil, either periodical or non-periodical aerodynamic forces can be generated. Real airfoils are usually flexible so that the effect of flexibility on unsteady characteristics of aerodynamic periodicity should be considered. In this study, a fluid structure interaction analysis is employed to systematically investigate the aerodynamic periodicity of a periodically plunging flexible airfoil. The influences of several dimensionless kinematic and structural parameters on aerodynamic periodicity are investigated. The results show that the aerodynamic periodicity of plunging flexible airfoil qualitatively resembles that of rigid airfoil as the mechanisms contributing to aerodynamic periodicity are kept for airfoil with various flexibilities. However, aerodynamic periodicity at small plunging amplitude and high Reynolds number can be improved as airfoil becomes medium flexible but worsened as airfoil is very flexible. The reason is that the deformation of the airfoil changes the strength and structure of the nearby vortices, thereby leading to weak vortex–vortex and vortex–airfoil interactions. The extent of improvement in aerodynamic periodicity is also found significantly influenced by incoming velocity.     

发电-储能一体化柔性电源系统结构热特性仿真研究

基于柔性薄膜砷化镓(GaAs)太阳电池、全固态薄膜锂电池(TFB)和柔性管理电路组成的发电-储能结构一体化电源系统,可以用作便携式应急电源,也可与无人飞行器、便捷式电子设备、无线传感网络节点等结合,实现自身能源的闭合供给,满足相关装备对电能源全天候、长时间、模块化等多样化应用的需求。但在实际工作中,系统的电转化效率只有30%左右,大部分太阳光的能量经太阳电池吸收后会转化成热,TFB在充电过程中也会发热。电源系统中,柔性太阳电池和TFB采用键合的方式结合,由于薄膜各层材料的热膨胀系数不同,产生的热量会在电源系统内部导致热应力,造成键合材料的分离,甚至破坏整个电源系统。通过计算机模拟柔性电源系统在月球表面环境下的工作状态,建立电源系统结构模型以及热传递数学模型,仿真得到不同结构电源系统工作时的温度场和应力场分布情况,对发电-储能一体化柔性电源系统结构优化和工作状态的掌握具有指导意义。     

某机翼疲劳寿命估算

对整个机翼进行了有限元分析,危险孔周围的细节分析使用精确的三维元,计算中考虑了复杂载荷历程,选取了几个飞行姿态。机翼危险部位寿命估算结果与疲劳试验一致。