倒圆角三角型两轴柔性支撑设计

为提高压电陶瓷驱动的快速反射镜的回转精度,对倒圆角三角型柔性支撑进行研究。首先利用卡氏第二定理推导出倒圆角三角型柔性铰链柔度和回转精度理论计算公式;然后建立倒圆角三角型柔性铰链和两轴柔性支撑的有限元模型,并进行仿真分析得出柔度和回转精度的仿真值。将仿真值与理论值进行比较,其结果表明,最大误差在8%以内,验证了所推导公式的准确性。对比直圆型柔性支撑,在保证柔度的前提下,倒圆角三角型柔性支撑的回转精度提高了40%,具有重要的工程实用价值。     

蜂巢柔性导向结构设计及分析

柔性铰链导向机构作为压电驱动器基本导向及保护单元,被广泛应用于各类复杂柔性机构中,然而现行导向机构仍存在许多不足。该文设计了一种基于蜂巢柔性铰链的对称结构用于压电驱动器运动导向,采用有限元法详细分析了其动静态运动特性。着重研究了机构性能对关键结构参数的依赖规律,给出了相应经验设计公式以用于指导其参数最优设计。所设计的蜂巢柔性导向机构具有机构紧凑,易于实现大行程导向,反应速率快等优点,具有重要的工程实用价值。     

TMT三镜镜室组件柔性结构设计与屈曲分析

30 m望远镜三镜为长轴3.594 m,短轴2.536 m的椭圆形微晶玻璃反射镜。其支撑结构采用了多种柔性结构,以释放非支撑方向的自由度。使得轴向支承和侧向支撑能够相互解耦,并减小支撑结构与镜子材料的热胀系数不匹配带来的热应力。柔性件柔度越高,在望远镜观测条件的扰动下镜面面形越好。但过高的柔度会降低柔性件的屈曲临界载荷,导致结构发生屈曲失效。为此需要计算出望远镜观测过程中柔性结构所承受的最大压力载荷,计算相应的屈曲安全系数SFBuckling。对比了典型结构非线性屈曲分析和特征值屈曲分析的区别,不断迭代设计和分析,柔性元件的SFBuckling和柔度取得了一个较好的平衡点,热扰动下的面形也达到了设计要求。     

大口径透镜混合柔性支撑结构优化设计

针对大口径透镜,提出了一种新型混合柔性支撑结构,能够使透镜同时满足面形精度及位置精度要求。首先利用卡氏第二定理对各柔性铰链进行分析,建立支撑组件整体柔度模型。然后以柔性支撑组件的总变形能为目标函数,以位置精度及实际使用空间要求为约束,建立结构优化设计模型。之后确定径向柔性支撑结构对组件整体柔度的敏感度最大并对其刚度进行验证。最后对优化后的透镜组件整体结构进行有限元分析,同时利用曲面拟合方法计算镜面面形精度。仿真结果表明,在该新型混合柔性支撑结构的作用下,透镜在各要求工况下的面形精度均优于λ/20 (λ=632.8 nm)。所设计的新型混合柔性支撑结构及其理论分析过程可为高精度大口径透镜的支撑技术提供参考。     

波导E面金属膜片滤波器在Tee型功分器中的应用

波导E面金属膜片滤波器是毫米波波段广泛使用的一种滤波器。波导Tee型功分器是波导中常用的弯曲结构。将波导E面金属膜片滤波器和Tee型功分器相结合,节省了大量的空间。通过CAD仿真,分析了Tee型弯曲结构对于波导E面金属膜片滤波器性能的影响。     

切向双脚架-运动学支撑结构的柔度研究

为了实现高精度的运动学支撑结构的设计,研究了切向双脚架-运动学支撑结构的柔度。介绍了切向双脚架-运动学支撑结构的设计原理。根据单边直圆柔性铰链的柔度公式,推导了双脚架在X、Y和Z轴方向的等效柔度Cx、Cy和Cz的解析式。采用有限元分析和试验验证的方法,对双脚架的柔度解析式进行了分析验证。结果表明:解析式结果与有限元结果、试验结果基本一致,且误差均小于9.8%。研究了单边直圆柔性铰链的柔槽深度R和最小厚度t对双脚架柔度Cx、Cy和Cz的影响,得到了双脚架的等效柔度均与柔槽深度R成正比,与最小厚度t成反比的结论。为空间相机上的科学仪器的切向双脚架-运动学支撑结构的设计提供理论参考。     

直圆抛物线复合铰链柔度研究

提出了一种新型柔性铰链:双边直圆抛物线复合铰链,建立了其理论结构模型,利用卡氏第二定理及微积分理论对铰链的主要性能指标柔度和转动精度进行计算,并取实际参数对柔度及转动精度进行了理论计算及有限元分析,同时对影响铰链性能的结构参数进行研究,结果表明:铰链柔度及转动精度的理论值与有限元分析值相比较,一致性大于92%,且铰链柔度随最小切割厚度t的变化最大。作为一种新型铰链与其他柔性铰链进行了对比,直圆抛物线铰链融合了直圆铰链与抛物线铰链的优点,当cL/2时,铰链具有较强的转动性能及较弱的载荷敏感性,且热适应能力更强。所设计的直圆抛物线铰链为包括空间环境使用的支撑结构柔节的设计提供了指导。     

压电驱动三维超微定位平台的性能研究

提出一种以柔性铰链结构为导向机构、压电陶瓷为驱动器的三维超微定位工作台,对三维超微定位工作台的非线性和动态特性的问题进行了研究,提出改善方法以提高系统的定位性能。将三维超微定位平台用于微操作机械手。     

新型混合柔性铰链柔度研究

提出了一种新型双曲线直圆混合柔性铰链。利用卡氏第二定理推导出双曲线直圆混合柔性铰链的柔度计算公式,并根据所推导的公式,分析了直圆半径、最小厚度和切割深度对其柔度的影响。同时采用实体单元建立双曲线直圆混合柔性铰链的有限元模型,对不同几何参数的铰链进行仿真分析,并对仿真解与解析解进行对比。结果表明:仿真解与解析解的最大误差在8%以内,证明了所推导公式的正确性;与不同形状的柔性铰链对比得出,双曲线直圆混合柔性铰链具有更好的转动能力和对载荷较高的敏感性。所设计的新型双曲线直圆混合柔性铰链更适用于快速反射镜支撑结构中,同时也为混合型柔性铰链的设计和优化提供了理论依据。     

人工全膝关节置换术后早期感染的治疗

设计一种以压电陶瓷为驱动,通过柔性机构放大输出位移的精密定位工作台.给出了该精密定位工作台的结构模型,建立了精密定位工作台的位置输入输出方程,分析和计算了柔性铰链微位移放大机构的位移放大倍数.通过仿真确定工作台各自由度的变形量与压电陶瓷驱动器伸缩量之间的关系与运动特性.结果表明,该精密定位工作台能实现定位误差为0.1 μm的高精度定位.通过与3点支撑微位移放大机构工作台的比较,显示出4点支撑微位移放大机构工作台可减小交叉耦合的影响.     

2 m 望远镜K 镜支撑结构优化设计

为了使得某2m望远镜消旋K镜在重力环境温度变化的影响下镜面面形和结构刚度满足要求,设计了一种柔性支撑结构。KM1 支撑方式采用背部三点支撑,通过有限元软件ANSYS 对支撑位置进行优化。并基于伴随变换建立了柔性支撑杆的柔度矩阵,对柔性铰链的厚度、长度和宽度进行优化,使反射镜支撑刚度满足需求,并减轻热应力和装配应力面形的影响。KM2 采用周边三点支撑,间隔120均匀分布,支撑杆结构与KM1 相同。在重力和均匀温降的联合工况下,KM1 和KM2 的有限元仿真结果达到了设计要求,KM1 镜面面形RMS 低于/40,KM2 镜面面形RMS 低于/60,一阶谐振频率均高于100 Hz。     

功率LED柔性封装结构的设计与热特性分析

根据功率LED的柔性封装要求,提出了基于贴片式(SMD)封装的功率型LED柔性封装结构。对各层结构进行了优化设计,采用有限元分析(FEA),模拟了柔性封装结构LED的热场分布。对比研究了柔性LED与传统封装结构LED的热特性,并对弯曲状态下柔性衬底材料对芯片的应力进行了分析。结果表明,采用金属Cu箔衬底的柔性封装结构,其散热特性较好;Cu/超薄玻璃复合衬底替代Cu箔衬底,可以减少弯曲的应力,减少幅度达到2.5倍,散热特性基本相同。SMD柔性封装的LED不仅具有较好的热稳定性,且具有柔性可挠曲特性,其应用潜力很大。     

动态特性可调的微动平台优化设计

针对目前柔性铰链主要靠局部变形来工作,其存在应力集中,且微动平台的动态特性受材料特性、设计制造等误差影响,难以满足变工况条件下的高精密位移输出。基于应力刚化原理,采用对称布置的带倒角的弹片式柔性铰链,设计张紧力调节机构,实现微动平台的动态特性可调。采用COMSOL Multiphysics和MATLAB联合仿真对张紧力调节机构进行参数优化,让调节机构保持线性调节关系,使柔性铰链的应力分布最小化。结果表明,所设计的微动平台能够进行高度线性固有频率调节,与有限元分析结果相比,频率调节范围相差2.55%,在理论设计范围内。     

Highly Stable and Active Flexible Electrocatalysts Derived from Lotus Fibers

The stability and activity of electrocatalysts are fundamental in energy-related applications (e.g., hydrogen generation and energy storage). Electrocatalysts degrade over time when the active centers are not strongly anchored to the support. However, if the active centers are too strongly anchored, the activity of the electrocatalysts decreases due to reduced accessibility to reactants. Herein, a strategy is presented to balance the stability and activity of different active materials using a natural and flexible support material that can be woven and carbonized. Lotus fibers, which have surface hydroxyl and phenolic groups, high mechanical strength, and a mesoscale porosity post-pyrolysis, are used to load diverse functional metal-containing materials such as metal–organic frameworks, 2D materials, metal sulfide nanoparticles, metal ions, and high-entropy alloys. After pyrolysis, the electrocatalysts display flexibility, high catalytic performance, and long-term stability, outperforming commercial benchmarks (e.g., Pt/C) in specific scenarios for water splitting, liquid batteries, and flexible electronics.     

Biomimetic Honeycomb Zn Anode Enabled Multi-Field Regulation toward Highly Stable Flexible Zn-Ion Batteries

Flexible Zn-ion batteries (ZIBs) emerge as a promising entrant for flexible and safe energy systems in the post-Li era, while the instability of Zn anode including inferior flexibility, uncontrollable plating, and dendrite growth remains a challenge. Naturally inspired, a topology-optimized biomimetic honeycomb Zn (BH-Zn) anode through mechanical-electrochemical processing is demonstrated. Numerical simulations and experimental observations reveal the BH-Zn engenders smooth current–stress–thermal field distributions, concurrently realizing the multi-field regulation effect and boosted stability. After in situ alloying, the BH-Zn enables half-diminished voltage polarization, superior electrochemical stability of 2000 h cycling, and thermal stability even at 30 mA cm⁻². Moreover, the assembled ZIBs manifest over 20 times enhanced capacity retention and are integrated as a self-powered wearable system for real-time health monitoring. This strategy can be extended to customizable metal anodes and promises to be applied in stable flexible batteries.     

柔性轴在卫星光通信中的使用与优化设计

针对卫星光通信粗跟踪系统中机械轴存在空回、轴系摩擦、轴间隙的不足的问题,提出采用柔性轴支撑光端机的方案。首先介绍了采用柔性轴卫星光通信的原理;然后分析了柔铰工作方向的柔度、最小切割处应力特性;从关键点挠度出发推导了回转误差角表达式,并分析了回转误差角对捕获性能的影响;在柔性轴特性研究的基础上,采用遗传算法对柔性铰链进行了优化设计。设计结果为:柔性铰链工作方向柔度0.768 rad/Nm,最小切割处应力1.768e+8 Pa,回转误差角343 rad;最后采用有限元法对设计结果进行了验证,三项指标的相对误差均小于3.5%,证明设计是可靠的。研究内容可为采用柔性轴的卫星光通信系统设计提供一定参考。     

All‐Carbon‐Electrode‐Based Endurable Flexible Perovskite Solar Cells

Endured, low‐cost, and high‐performance flexible perovskite solar cells (PSCs) featuring lightweight and mechanical flexibility have attracted tremendous attention for portable power source applications. However, flexible PSCs typically use expensive and fragile indium–tin oxide as transparent anode and high‐vacuum processed noble metal as cathode, resulting in dramatic performance degradation after continuous bending or thermal stress. Here, all‐carbon‐electrode‐based flexible PSCs are fabricated employing graphene as transparent anode and carbon nanotubes as cathode. All‐carbon‐electrode‐based flexible devices with and without spiro‐OMeTAD (2,2′,7,7′‐tetrakis‐(N,N‐di‐p‐methoxyphenylamine)‐9,9′‐spirobifluorene) hole conductor achieve power conversion efficiencies (PCEs) of 11.9% and 8.4%, respectively. The flexible carbon‐electrode‐based solar cells demonstrate superior robustness against mechanical deformation in comparison with their counterparts fabricated on flexible indium–tin oxide substrates. Moreover, all carbon‐electrode‐based flexible PSCs also show significantly enhanced stability compared to the flexible devices with gold and silver cathodes under continuous light soaking or 60 °C thermal stress in air, retaining over 90% of their original PCEs after 1000 h. The promising durability and stability highlight that flexible PSCs are fully compatible with carbon materials and pave the way toward the realization of rollable and low‐cost flexible perovskite photovoltaic devices.     

Ultrathin Metal films for Transparent Electrodes of Flexible Optoelectronic Devices

The need for the development of transparent conductive electrodes (TCEs) supported on flexible polymer substrates has explosively increased in response to flexible polymer‐based photovoltaic and display technologies; these TCEs replace conventional indium tin oxide (ITO) that exhibits poor performance on heat‐sensitive polymers. An efficient, flexible TCE is required to exhibit high electrical conductance and high optical transmittance, as well as excellent mechanical flexibility and long‐term stability, simultaneously. Recent advances in technologies utilizing an ultrathin noble‐metal film in a dielectric/metal/dielectric structure, or its derivatives, have attracted attention as promising alternatives that can satisfy the requirements of flexible TCEs. This review will survey the background knowledge and recent updates of synthetic strategies and design rules toward highly efficient, flexible TCEs based on ultrathin metal films, with a special focus on the principal features and available methodologies involved in the fabrication of highly transparent, conductive, ultrathin noble‐metal films. This survey will also cover the practical applications of TCEs to flexible organic solar cells and light‐emitting diodes.     

SiC轻量化主镜液压whiffletree支撑系统的改进

针对2 m SiC轻量化主镜设计了液压whiffletree被动支撑系统,通过在轴向液压支撑点处并联杠杆配重机构的方式,实现了不同支撑圈上轴向支撑力的优化分配,将轴向支撑下主镜的镜面变形RMS值从7.1 nm优化到4.8 nm.针对SiC主镜热膨胀率大的特性,提出了采用具有热解耦能力的切向连杆结合液压whiffletree的侧向支撑系统,并借助于有限元法预算出主镜光轴水平状态下侧向支撑引起的镜面变形误差RMS值为39.7 nm.当温差为20 ℃时,轴向和侧向支撑结构作用下的主镜镜面变形误差RMS值仍保持在4.8 nm,验证了侧向支撑良好的热解耦能力.